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Find video protocols related to scientific articles indexed in Pubmed.
RNF213 Rare Variants in an Ethnically Diverse Population With Moyamoya Disease.
Stroke
PUBLISHED: 10-02-2014
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Moyamoya disease (MMD) is a rare, genetically heterogeneous cerebrovascular disease resulting from occlusion of the distal internal carotid arteries. A variant in the Ring Finger 213 gene (RNF213), altering arginine at position 4810 (p.R4810K), is associated with MMD in Asian populations. However, there are a lack of data on the role of RNF213 in patients with MMD of additional ethnicities and diasporic Asian populations. We investigate the contribution of RNF213 alterations to MMD in an ethnically diverse population based in the United States.
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Use of genetics for personalized management of heritable thoracic aortic disease: How do we get there?
J. Thorac. Cardiovasc. Surg.
PUBLISHED: 05-30-2014
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The major diseases affecting the thoracic aorta are aortic aneurysms and acute aortic dissections. Medical treatments can slow the enlargement of aneurysms, but the mainstay of treatment to prevent premature death resulting from dissection is surgical repair of the thoracic aortic aneurysm, which is typically recommended when the aortic diameter reaches 5.0 to 5.5 cm. Studies of patients with acute aortic dissections, however, indicate that as many as 60% of dissections occur at aortic diameters smaller than 5.5 cm. Clinical predictors are therefore needed to distinguish those at risk for dissection at an aortic diameter smaller than 5.0 cm and to determine the aortic diameter that justifies the risk of surgical repair to prevent an acute aortic dissection. Data from genetic studies during the past decade have established that mutations in specific genes can distinguish patients at risk for the disease and predict the risk of early dissection at diameters smaller than 5.0 cm. This information has the potential to optimize the timing of aortic surgery to prevent acute dissections.
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Clinical and biochemical profiles suggest fibromuscular dysplasia is a systemic disease with altered TGF-? expression and connective tissue features.
FASEB J.
PUBLISHED: 04-14-2014
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Fibromuscular dysplasia (FMD) is a rare, nonatherosclerotic arterial disease for which the molecular basis is unknown. We comprehensively studied 47 subjects with FMD, including physical examination, spine magnetic resonance imaging, bone densitometry, and brain magnetic resonance angiography. Inflammatory biomarkers in plasma and transforming growth factor ? (TGF-?) cytokines in patient-derived dermal fibroblasts were measured by ELISA. Arterial pathology other than medial fibrodysplasia with multifocal stenosis included cerebral aneurysm, found in 12.8% of subjects. Extra-arterial pathology included low bone density (P<0.001); early onset degenerative spine disease (95.7%); increased incidence of Chiari I malformation (6.4%) and dural ectasia (42.6%); and physical examination findings of a mild connective tissue dysplasia (95.7%). Screening for mutations causing known genetically mediated arteriopathies was unrevealing. We found elevated plasma TGF-?1 (P=0.009), TGF-?2 (P=0.004) and additional inflammatory markers, and increased TGF-?1 (P=0.0009) and TGF-?2 (P=0.0001) secretion in dermal fibroblast cell lines from subjects with FMD compared to age- and gender-matched controls. Detailed phenotyping of patients with FMD allowed us to demonstrate that FMD is a systemic disease with alterations in common with the spectrum of genetic syndromes that involve altered TGF-? signaling and offers TGF-? as a marker of FMD.
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Overexpression of smooth muscle myosin heavy chain leads to activation of the unfolded protein response and autophagic turnover of thick filament-associated proteins in vascular smooth muscle cells.
J. Biol. Chem.
PUBLISHED: 04-07-2014
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Duplications spanning nine genes at the genomic locus 16p13.1 predispose individuals to acute aortic dissections. The most likely candidate gene in this region leading to the predisposition for dissection is MYH11, which encodes smooth muscle myosin heavy chain (SM-MHC). The effects of increased expression of MYH11 on smooth muscle cell (SMC) phenotypes were explored using mouse aortic SMCs with transgenic overexpression of one isoform of SM-MHC. We found that these cells show increased expression of Myh11 and myosin filament-associated contractile genes at the message level when compared with control SMCs, but not at the protein level due to increased protein degradation. Increased expression of Myh11 resulted in endoplasmic reticulum (ER) stress in SMCs, which led to a paradoxical decrease of protein levels through increased autophagic degradation. An additional consequence of ER stress in SMCs was increased intracellular calcium ion concentration, resulting in increased contractile signaling and contraction. The increased signals for contraction further promote transcription of contractile genes, leading to a feedback loop of metabolic abnormalities in these SMCs. We suggest that overexpression of MYH11 can lead to increased ER stress and autophagy, findings that may be globally implicated in disease processes associated with genomic duplications.
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Molecular diagnosis in vascular Ehlers-Danlos syndrome predicts pattern of arterial involvement and outcomes.
J. Vasc. Surg.
PUBLISHED: 01-30-2014
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The management of arterial pathology in individuals with vascular Ehlers-Danlos syndrome (vEDS) remains a challenge. Here we describe the correlation between COL3A1 gene mutation type and the clinical phenotype in individuals with vEDS.
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Advanced atherosclerosis is associated with increased medial degeneration in sporadic ascending aortic aneurysms.
Atherosclerosis
PUBLISHED: 01-29-2014
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The pathogenesis of non-familial, sporadic ascending aortic aneurysms (SAAA) is poorly understood, and the relationship between ascending aortic atherosclerosis and medial degeneration is unclear. We evaluated the prevalence and severity of aortic atherosclerosis and its association with medial degeneration in SAAA.
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IL-6 regulates extracellular matrix remodeling associated with aortic dilation in a fibrillin-1 hypomorphic mgR/mgR mouse model of severe Marfan syndrome.
J Am Heart Assoc
PUBLISHED: 01-23-2014
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Development of thoracic aortic aneurysms is the most significant clinical phenotype in patients with Marfan syndrome. An inflammatory response has been described in advanced stages of the disease. Because the hallmark of vascular inflammation is local interleukin-6 (IL-6) secretion, we explored the role of this proinflammatory cytokine in the formation of aortic aneurysms and rupture in hypomorphic fibrillin-deficient mice (mgR/mgR).
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A roadmap to investigate the genetic basis of bicuspid aortic valve and its complications: insights from the International BAVCon (Bicuspid Aortic Valve Consortium).
J. Am. Coll. Cardiol.
PUBLISHED: 01-19-2014
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Bicuspid aortic valve (BAV) is the most common adult congenital heart defect and is found in 0.5% to 2.0% of the general population. The term "BAV" refers to a heterogeneous group of disorders characterized by diverse aortic valve malformations with associated aortopathy, congenital heart defects, and genetic syndromes. Even after decades of investigation, the genetic determinants of BAV and its complications remain largely undefined. Just as BAV phenotypes are highly variable, the genetic etiologies of BAV are equally diverse and vary from complex inheritance in families to sporadic cases without any evidence of inheritance. In this paper, the authors discuss current concepts in BAV genetics and propose a roadmap for unraveling unanswered questions about BAV through the integrated analysis of genetic and clinical data.
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Early and 1-year outcomes of aortic root surgery in patients with Marfan syndrome: a prospective, multicenter, comparative study.
J. Thorac. Cardiovasc. Surg.
PUBLISHED: 01-17-2014
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To compare the 1-year results after aortic valve-sparing (AVS) or valve-replacing (AVR) aortic root replacement from a prospective, international registry of 316 patients with Marfan syndrome (MFS).
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Aortic remodeling after transverse aortic constriction in mice is attenuated with AT1 receptor blockade.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 07-18-2013
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Although hypertension is the most common risk factor for thoracic aortic diseases, it is not understood how increased pressures on the ascending aorta lead to aortic aneurysms. We investigated the role of angiotensin II type 1 receptor activation in ascending aortic remodeling in response to increased biomechanical forces using a transverse aortic constriction (TAC) mouse model.
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Acute aortic dissections with pregnancy in women with ACTA2 mutations.
Am. J. Med. Genet. A
PUBLISHED: 05-23-2013
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Mutations in ACTA2 predispose to thoracic aortic aneurysms and dissection as well as coronary artery and cerebrovascular disease. Here we examined the risk of aortic dissections, stroke and myocardial infarct with pregnancy in women with ACTA2 mutations. Of the 53 women who had a total of 137 pregnancies, eight had aortic dissections in the third trimester or the postpartum period (6% of pregnancies). One woman also had a myocardial infarct that occurred during pregnancy that was independent of her aortic dissection. Compared to the population-based frequency of peripartum aortic dissections of 0.6%, the rate of peripartum aortic dissections in women with ACTA2 mutations is much higher (8 out of 39; 20%). Six of these dissections initiated in the ascending aorta (Stanford type A), three were fatal. Three women had ascending aortic dissections at diameters less that 5.0?cm (range 3.8-4.7?cm). Aortic pathology showed mild to moderate medial degeneration of the aorta in three women. Of note, five of the women had hypertension either during or before the pregnancy. In summary, the majority of women with ACTA2 mutations did not have aortic or other vascular complications with pregnancy. However, these findings show that pregnancy is associated with significant risk for aortic dissection in women with ACTA2 mutations. Women with ACTA2 mutations who are planning to get pregnant should be counseled about this risk of aortic dissection, and proper clinical management should be initiated to reduce this risk. © 2013 Wiley Periodicals, Inc.
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Interleukin-6-signal transducer and activator of transcription-3 signaling mediates aortic dissections induced by angiotensin II via the T-helper lymphocyte 17-interleukin 17 axis in C57BL/6 mice.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 05-16-2013
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Dysregulated angiotensin II (Ang II) signaling induces local vascular interleukin-6 (IL-6) secretion, producing leukocyte infiltration and life-threatening aortic dissections. Precise mechanisms by which IL-6 signaling induces leukocyte recruitment remain unknown. T-helper 17 lymphocytes (Th17) have been implicated in vascular pathology, but their role in the development of aortic dissections is poorly understood. Here, we tested the relationship of IL-6-signal transducer and activator of transcription-3 signaling with Th17-induced inflammation in the formation of Ang II-induced dissections in C57BL/6 mice.
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Successes and challenges of using whole exome sequencing to identify novel genes underlying an inherited predisposition for thoracic aortic aneurysms and acute aortic dissections.
Trends Cardiovasc. Med.
PUBLISHED: 05-07-2013
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Thoracic aortic aneurysms involving the aortic root and/or ascending aorta can lead to acute aortic dissections. Approximately 20% of patients with thoracic aortic aneurysms and dissections (TAAD) have a family history of the disease, referred to as familial TAAD (FTAAD) that can be inherited in an autosomal dominant manner with variable expression with respect to disease presentation, age of onset and associated features. Whole exome sequencing (WES) has been used to identify causative mutations in novel genes for TAAD. The strategy used to reduce the large number of rare variants identified using WES is to sequence distant relatives with TAAD and filter for heterozygous rare variants that are shared between the relatives, predicted to disrupt protein function and segregate with the TAAD phenotype in other family members. Putative genes are validated by identifying additional families with a causative mutation in the genes. This approach has successfully identified novel genes for FTAAD.
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Single-nucleotide polymorphism array genotyping is equivalent to metaphase cytogenetics for diagnosis of Turner syndrome.
Genet. Med.
PUBLISHED: 04-18-2013
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Purpose:Turner syndrome is a developmental disorder caused by partial or complete monosomy for the X chromosome in 1 in 2,500 females. We hypothesized that single-nucleotide polymorphism (SNP) array genotyping could provide superior resolution in comparison to metaphase karyotype analysis to facilitate genotype-phenotype correlations.Methods:We genotyped 187 Turner syndrome patients with 733,000 SNP marker arrays. All cases met diagnostic criteria for Turner syndrome based on karyotypes (60%) or characteristic physical features. The SNP array results confirmed the diagnosis of Turner syndrome in 100% of cases.Results:We identified a single X chromosome (45,X) in 113 cases. In 58 additional cases (31%), other mosaic cell lines were present, including isochromosomes (16%), rings (5%), and Xp deletions (8%). The remaining cases were mosaic for monosomy X and normal male or female cell lines. Array-based models of X chromosome structure were compatible with karyotypes in 104 of 116 comparable cases (90%). We found that the SNP array data did not detect X-autosome translocations (three cases) but did identify two derivative Y chromosomes and 13 large copy-number variants that were not detected by karyotyping.Conclusion:Our study is the first systematic comparison between the two methods and supports the utility of SNP array genotyping to address clinical and research questions in Turner syndrome.Genet Med advance online publication 6 June 2013Genetics in Medicine (2013); doi:10.1038/gim.2013.77.
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Smooth muscle hyperplasia due to loss of smooth muscle ?-actin is driven by activation of focal adhesion kinase, altered p53 localization and increased levels of platelet-derived growth factor receptor-?.
Hum. Mol. Genet.
PUBLISHED: 04-15-2013
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Mutations in ACTA2, encoding the smooth muscle cell (SMC)-specific isoform of ?-actin (?-SMA), cause thoracic aortic aneurysms and dissections and occlusive vascular diseases, including early onset coronary artery disease and stroke. We have shown that occlusive arterial lesions in patients with heterozygous ACTA2 missense mutations show increased numbers of medial or neointimal SMCs. The contribution of SMC hyperplasia to these vascular diseases and the pathways responsible for linking disruption of ?-SMA filaments to hyperplasia are unknown. Here, we show that the loss of Acta2 in mice recapitulates the SMC hyperplasia observed in ACTA2 mutant SMCs and determine the cellular pathways responsible for SMC hyperplasia. Acta2(-/-) mice showed increased neointimal formation following vascular injury in vivo, and SMCs explanted from these mice demonstrated increased proliferation and migration. Loss of ?-SMA induced hyperplasia through focal adhesion (FA) rearrangement, FA kinase activation, re-localization of p53 from the nucleus to the cytoplasm and increased expression and ligand-independent activation of platelet-derived growth factor receptor beta (Pdgfr-?). Disruption of ?-SMA in wild-type SMCs also induced similar cellular changes. Imatinib mesylate inhibited Pdgfr-? activation and Acta2(-/-) SMC proliferation in vitro and neointimal formation with vascular injury in vivo. Loss of ?-SMA leads to SMC hyperplasia in vivo and in vitro through a mechanism involving FAK, p53 and Pdgfr-?, supporting the hypothesis that SMC hyperplasia contributes to occlusive lesions in patients with ACTA2 missense mutations.
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Recurrent gain-of-function mutation in PRKG1 causes thoracic aortic aneurysms and acute aortic dissections.
Am. J. Hum. Genet.
PUBLISHED: 04-12-2013
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Gene mutations that lead to decreased contraction of vascular smooth-muscle cells (SMCs) can cause inherited thoracic aortic aneurysms and dissections. Exome sequencing of distant relatives affected by thoracic aortic disease and subsequent Sanger sequencing of additional probands with familial thoracic aortic disease identified the same rare variant, PRKG1 c.530G>A (p.Arg177Gln), in four families. This mutation segregated with aortic disease in these families with a combined two-point LOD score of 7.88. The majority of affected individuals presented with acute aortic dissections (63%) at relatively young ages (mean 31 years, range 17-51 years). PRKG1 encodes type I cGMP-dependent protein kinase (PKG-1), which is activated upon binding of cGMP and controls SMC relaxation. Although the p.Arg177Gln alteration disrupts binding to the high-affinity cGMP binding site within the regulatory domain, the altered PKG-1 is constitutively active even in the absence of cGMP. The increased PKG-1 activity leads to decreased phosphorylation of the myosin regulatory light chain in fibroblasts and is predicted to cause decreased contraction of vascular SMCs. Thus, identification of a gain-of-function mutation in PRKG1 as a cause of thoracic aortic disease provides further evidence that proper SMC contractile function is critical for maintaining the integrity of the thoracic aorta throughout a lifetime.
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GenTAC registry report: gender differences among individuals with genetically triggered thoracic aortic aneurysm and dissection.
Am. J. Med. Genet. A
PUBLISHED: 02-26-2013
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Previous data suggest women are at increased risk of death from aortic dissection. Therefore, we analyzed data from the GenTAC registry, the NIH-sponsored program that collects information about individuals with genetically triggered thoracic aortic aneurysms and cardiovascular conditions. We performed cross-sectional analyses in adults with Marfan syndrome (MFS), familial thoracic aortic aneurysm or dissection (FTAAD), bicuspid aortic valve (BAV) with thoracic aortic aneurysm or dissection, and subjects under 50 years of age with thoracic aortic aneurysm or dissection (TAAD <50 years). Women comprised 32% of 1,449 subjects and were 21% of subjects with BAV, 34% with FTAAD, 22% with TAAD <50 years, and 47% with MFS. Thoracic aortic dissections occurred with equal gender frequency yet women with BAV had more extensive dissections. Aortic size was smaller in women but was similar after controlling for BSA. Age at operation for aortic valve dysfunction, aneurysm or dissection did not differ by gender. Multivariate analysis (adjusting for age, BSA, hypertension, study site, diabetes, and subgroup diagnoses) showed that women had fewer total aortic surgeries (OR = 0.65, P < 0.01) and were less likely to receive angiotensin converting enzyme inhibitors (ACEi; OR = 0.68, P < 0.05). As in BAV, other genetically triggered aortic diseases such as FTAAD and TAAD <50 are more common in males. In women, decreased prevalence of aortic operations and less treatment with ACEi may be due to their smaller absolute aortic diameters. Longitudinal studies are needed to determine if women are at higher risk for adverse events.
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Coagulation factor V(A2440G) causes east Texas bleeding disorder via TFPI?.
J. Clin. Invest.
PUBLISHED: 01-29-2013
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The autosomal dominantly inherited east Texas bleeding disorder is linked to an A2440G variant in exon 13 of the F5 gene. Affected individuals have normal levels of coagulation factor V (FV) activity, but demonstrate inhibition of global coagulation tests. We demonstrated that the A2440G mutation causes upregulation of an alternatively spliced F5 transcript that results in an in-frame deletion of 702 amino acids of the large activation fragment, the B domain. The approximately 250-kDa FV isoform (FV-short), which can be fully activated by thrombin, is present in all A2440G carriers plasma (n = 16). FV-short inhibits coagulation through an indirect mechanism by forming a complex with tissue factor pathway inhibitor-? (TFPI?), resulting in an approximately 10-fold increase in plasma TFPI?, suggesting that the TFPI?:FV-short complexes are retained in circulation. The TFPI?:FV-short complexes efficiently inhibit thrombin generation of both intrinsic and extrinsic coagulation pathways. These data demonstrate that the east Texas bleeding disorder-associated F5(A2440G) leads to the formation of the TFPI?:FV-short complex, which inhibits activation and propagation of coagulation.
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Missense mutations in FBN1 exons 41 and 42 cause Weill-Marchesani syndrome with thoracic aortic disease and Marfan syndrome.
Am. J. Med. Genet. A
PUBLISHED: 01-22-2013
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Mutations in FBN1 cause a range of overlapping but distinct conditions including Marfan syndrome (MFS), Weill-Marchesani syndrome (WMS), familial thoracic aortic aneurysms/dissections (FTAAD), acromicric dysplasia (AD), and geleophysic dysplasia (GD). Two forms of acromelic dysplasia, AD and GD, characterized by short stature, brachydactyly, reduced joint mobility, and characteristic facies, result from heterozygous missense mutations occurring in exons 41 and 42 of FBN1; missense mutations in these exons have not been reported to cause MFS or other syndromes. Here we report on probands with MFS and WMS who have heterozygous FBN1 missense mutations in exons 41 and 42, respectively. The proband with WMS has ectopia lentis, short stature, thickened pinnae, tight skin, striae atrophicae, reduced extension of the elbows, contractures of the fingers and toes, and brachydactyly and has a missense mutation in exon 42 of FBN1 (c.5242T>C; p.C1748R). He also experienced a previously unreported complication of WMS, an acute thoracic aortic dissection. The second proband displays classic characteristics of MFS, including ectopia lentis, skeletal features, and aortic root dilatation, and has a missense mutation in exon 41 of FBN1 (c.5084G>A; p.C1695Y). These phenotypes provide evidence that missense mutations in exons 41 and 42 of FBN1 lead to MFS and WMS in addition to AD and GD and also suggest that all individuals with pathogenic FBN1 mutations in these exons should be assessed for thoracic aortic disease and ectopia lentis. Further studies are necessary to elucidate the factors responsible for the different phenotypes associated with missense mutations in these exons of FBN1.
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Exome sequencing identifies SMAD3 mutations as a cause of familial thoracic aortic aneurysm and dissection with intracranial and other arterial aneurysms.
Circ. Res.
PUBLISHED: 07-21-2011
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Thoracic aortic aneurysms leading to acute aortic dissections (TAAD) can be inherited in families in an autosomal dominant manner. As part of the spectrum of clinical heterogeneity of familial TAAD, we recently described families with multiple members that had TAAD and intracranial aneurysms or TAAD and intracranial and abdominal aortic aneurysms inherited in an autosomal dominant manner.
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Long-term implications of emergency versus elective proximal aortic surgery in patients with Marfan syndrome in the Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions Consortium Registry.
J. Thorac. Cardiovasc. Surg.
PUBLISHED: 05-25-2011
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Patients with Marfan syndrome with aortic root aneurysms undergo elective aortic root replacement to avoid the life-threatening outcomes of aortic dissection and emergency repair. The long-term implications of failed aortic surveillance leading to acute dissection and emergency repair are poorly defined. We compared the long-term clinical courses of patients with Marfan syndrome who survive emergency versus elective proximal aortic surgery.
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Genome-wide association study identifies a susceptibility locus for thoracic aortic aneurysms and aortic dissections spanning FBN1 at 15q21.1.
Nat. Genet.
PUBLISHED: 05-23-2011
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Although thoracic aortic aneurysms and dissections (TAAD) can be inherited as a single-gene disorder, the genetic predisposition in the majority of affected people is poorly understood. In a multistage genome-wide association study (GWAS), we compared 765 individuals who had sporadic TAAD (STAAD) with 874 controls and identified common SNPs at a 15q21.1 locus that were associated with STAAD, with odds ratios of 1.6-1.8 that achieved genome-wide significance. We followed up 107 SNPs associated with STAAD with P < 1 × 10(-5) in the region, in two separate STAAD cohorts. The associated SNPs fall into a large region of linkage disequilibrium encompassing FBN1, which encodes fibrillin-1. FBN1 mutations cause Marfan syndrome, whose major cardiovascular complication is TAAD. This study shows that common genetic variants at 15q21.1 that probably act via FBN1 are associated with STAAD, suggesting a common pathogenesis of aortic disease in Marfan syndrome and STAAD.
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Recurrent chromosome 16p13.1 duplications are a risk factor for aortic dissections.
PLoS Genet.
PUBLISHED: 04-19-2011
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Chromosomal deletions or reciprocal duplications of the 16p13.1 region have been implicated in a variety of neuropsychiatric disorders such as autism, schizophrenia, epilepsies, and attention-deficit hyperactivity disorder (ADHD). In this study, we investigated the association of recurrent genomic copy number variants (CNVs) with thoracic aortic aneurysms and dissections (TAAD). By using SNP arrays to screen and comparative genomic hybridization microarrays to validate, we identified 16p13.1 duplications in 8 out of 765 patients of European descent with adult-onset TAAD compared with 4 of 4,569 controls matched for ethnicity (P = 5.0 × 10??, OR = 12.2). The findings were replicated in an independent cohort of 467 patients of European descent with TAAD (P = 0.005, OR = 14.7). Patients with 16p13.1 duplications were more likely to harbor a second rare CNV (P = 0.012) and to present with aortic dissections (P = 0.010) than patients without duplications. Duplications of 16p13.1 were identified in 2 of 130 patients with familial TAAD, but the duplications did not segregate with TAAD in the families. MYH11, a gene known to predispose to TAAD, lies in the duplicated region of 16p13.1, and increased MYH11 expression was found in aortic tissues from TAAD patients with 16p13.1 duplications compared with control aortas. These data suggest chromosome 16p13.1 duplications confer a risk for TAAD in addition to the established risk for neuropsychiatric disorders. It also indicates that recurrent CNVs may predispose to disorders involving more than one organ system, an observation critical to the understanding of the role of recurrent CNVs in human disease and a finding that may be common to other recurrent CNVs involving multiple genes.
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The National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC): results from phase I and scientific opportunities in phase II.
Am. Heart J.
PUBLISHED: 04-14-2011
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Genetically triggered thoracic aortic conditions (GenTACs) represent an important problem for patients and their families. Accordingly, the National Heart, Lung, and Blood Institute established the first phase of its national GenTAC Registry in 2006.
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The genetics of colored sequence synesthesia: suggestive evidence of linkage to 16q and genetic heterogeneity for the condition.
Behav. Brain Res.
PUBLISHED: 03-27-2011
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Synesthesia is a perceptual condition in which sensory stimulation triggers anomalous sensory experiences. In colored sequence synesthesia (CSS), color experiences are triggered by sequences such as letters or numbers. We performed a family based linkage analysis to identify genetic loci responsible for the increased neural crosstalk underlying CSS. Our results implicate a 23 MB region at 16q12.2-23.1, providing the first step in understanding the molecular basis of CSS.
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Autosomal dominant inheritance of a predisposition to thoracic aortic aneurysms and dissections and intracranial saccular aneurysms.
Am. J. Med. Genet. A
PUBLISHED: 03-20-2011
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A genetic predisposition for thoracic aortic aneurysms and dissections (TAAD) can be inherited in an autosomal dominant manner with decreased penetrance and variable expression. Four genes identified to date for familial TAAD account for approximately 20% of the heritable predisposition. In a cohort of 514 families with two or more members with presumed autosomal dominant TAAD, 48 (9.3%) families have one or more members who were at 50% risk to inherit the presumptive gene causing TAAD had an intracranial vascular event. In these families, gender is significantly associated with disease presentation (P?
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Susceptibility to acute thoracic aortic dissections in patients dying outside the hospital: an autopsy study.
Am. Heart J.
PUBLISHED: 02-25-2011
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The objectives of this study were to identify the incidence and predictors of death from acute thoracic aortic dissections (AoDs) and to describe their associated clinical findings.
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Impact of image analysis methodology on diagnostic and surgical classification of patients with thoracic aortic aneurysms.
Ann. Thorac. Surg.
PUBLISHED: 01-04-2011
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For patients with thoracic aortic aneurysms (TAA), aortic size on imaging is widely used to guide clinical decision making. This study examined the impact of methodological variance on aortic quantification.
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Familial thoracic aortic aneurysms and dissections: identification of a novel locus for stable aneurysms with a low risk for progression to aortic dissection.
Circ Cardiovasc Genet
PUBLISHED: 12-16-2010
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Thoracic aortic aneurysms leading to acute aortic dissections are the major diseases that affect the thoracic aorta. Approximately 20% of patients with thoracic aortic aneurysms and dissections (TAAD) have a family history of TAAD, and these patients present younger with more rapidly enlarging aneurysms than patients without a family history of aortic disease.
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Diffuse and uncontrolled vascular smooth muscle cell proliferation in rapidly progressing pediatric moyamoya disease.
J Neurosurg Pediatr
PUBLISHED: 09-03-2010
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Moyamoya disease is a rare stroke syndrome of unknown etiology resulting from stenosis or occlusion of the supraclinoid internal carotid artery (ICA) in association with an abnormal vascular network in the basal ganglia. Although the highest incidence of moyamoya disease is in pediatric patients, pathology reports have been primarily limited to adult samples and describe occlusive fibrocellular lesions in the intimae of affected arteries. We describe the case of a young girl with primary moyamoya disease who presented at 18 months of age with right hemiparesis following an ischemic stroke. Angiography showed stenosis of the distal left ICA, left middle cerebral artery, and right ICA. An emergent left-sided dural inversion was performed. Recurrent strokes and alternating hemiplegia necessitated a right dural inversion 6 months later. Nonetheless, her aggressive disease proved uniquely refractory to surgical revascularization, and she succumbed to recurrent strokes and neurological deterioration at 2.5 years of age. Pathological specimens revealed a striking bilateral occlusion of the anterior carotid circulation resulting from intimal proliferation of smooth muscle cells (SMCs). Most strikingly, the ascending aorta and the superior mesenteric artery demonstrated similar intimal proliferation, along with SMC proliferation in the media. The systemic pathology involving multiple arteries in this extremely young child, the first case of its kind available for autopsy, suggests that globally uncontrolled SMC proliferation, in the absence of environmental risk factors and likely resulting from an underlying genetic alteration, may be a primary etiologic event leading to moyamoya disease.
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De novo ACTA2 mutation causes a novel syndrome of multisystemic smooth muscle dysfunction.
Am. J. Med. Genet. A
PUBLISHED: 08-25-2010
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Smooth muscle cells (SMCs) contract to perform many physiological functions, including regulation of blood flow and pressure in arteries, contraction of the pupils, peristalsis of the gut, and voiding of the bladder. SMC lineage in these organs is characterized by cellular expression of the SMC isoform of ?-actin, encoded by the ACTA2 gene. We report here on a unique and de novo mutation in ACTA2, R179H, that causes a syndrome characterized by dysfunction of SMCs throughout the body, leading to aortic and cerebrovascular disease, fixed dilated pupils, hypotonic bladder, malrotation, and hypoperistalsis of the gut and pulmonary hypertension.
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Mutations in myosin light chain kinase cause familial aortic dissections.
Am. J. Hum. Genet.
PUBLISHED: 08-17-2010
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Mutations in smooth muscle cell (SMC)-specific isoforms of ?-actin and ?-myosin heavy chain, two major components of the SMC contractile unit, cause familial thoracic aortic aneurysms leading to acute aortic dissections (FTAAD). To investigate whether mutations in the kinase that controls SMC contractile function (myosin light chain kinase [MYLK]) cause FTAAD, we sequenced MYLK by using DNA from 193 affected probands from unrelated FTAAD families. One nonsense and four missense variants were identified in MYLK and were not present in matched controls. Two variants, p.R1480X (c.4438C>T) and p.S1759P (c.5275T>C), segregated with aortic dissections in two families with a maximum LOD score of 2.1, providing evidence of linkage of these rare variants to the disease (p = 0.0009). Both families demonstrated a similar phenotype characterized by presentation with an acute aortic dissection with little to no enlargement of the aorta. The p.R1480X mutation leads to a truncated protein lacking the kinase and calmodulin binding domains, and p.S1759P alters amino acids in the ?-helix of the calmodulin binding sequence, which disrupts kinase binding to calmodulin and reduces kinase activity in vitro. Furthermore, mice with SMC-specific knockdown of Mylk demonstrate altered gene expression and pathology consistent with medial degeneration of the aorta. Thus, genetic and functional studies support the conclusion that heterozygous loss-of-function mutations in MYLK are associated with aortic dissections.
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TGFBR2 mutations alter smooth muscle cell phenotype and predispose to thoracic aortic aneurysms and dissections.
Cardiovasc. Res.
PUBLISHED: 07-13-2010
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Transforming growth factor-? (TGF-?) signaling is critical for the differentiation of smooth muscle cells (SMCs) into quiescent cells expressing a full repertoire of contractile proteins. Heterozygous mutations in TGF-? receptor type II (TGFBR2) disrupt TGF-? signaling and lead to genetic conditions that predispose to thoracic aortic aneurysms and dissections (TAADs). The aim of this study is to determine the molecular mechanism by which TGFBR2 mutations cause TAADs.
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The revised Ghent nosology for the Marfan syndrome.
J. Med. Genet.
PUBLISHED: 07-02-2010
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The diagnosis of Marfan syndrome (MFS) relies on defined clinical criteria (Ghent nosology), outlined by international expert opinion to facilitate accurate recognition of this genetic aneurysm syndrome and to improve patient management and counselling. These Ghent criteria, comprising a set of major and minor manifestations in different body systems, have proven to work well since with improving molecular techniques, confirmation of the diagnosis is possible in over 95% of patients. However, concerns with the current nosology are that some of the diagnostic criteria have not been sufficiently validated, are not applicable in children or necessitate expensive and specialised investigations. The recognition of variable clinical expression and the recently extended differential diagnosis further confound accurate diagnostic decision making. Moreover, the diagnosis of MFS--whether or not established correctly--can be stigmatising, hamper career aspirations, restrict life insurance opportunities, and cause psychosocial burden. An international expert panel has established a revised Ghent nosology, which puts more weight on the cardiovascular manifestations and in which aortic root aneurysm and ectopia lentis are the cardinal clinical features. In the absence of any family history, the presence of these two manifestations is sufficient for the unequivocal diagnosis of MFS. In absence of either of these two, the presence of a bonafide FBN1 mutation or a combination of systemic manifestations is required. For the latter a new scoring system has been designed. In this revised nosology, FBN1 testing, although not mandatory, has greater weight in the diagnostic assessment. Special considerations are given to the diagnosis of MFS in children and alternative diagnoses in adults. We anticipate that these new guidelines may delay a definitive diagnosis of MFS but will decrease the risk of premature or misdiagnosis and facilitate worldwide discussion of risk and follow-up/management guidelines.
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Genetic testing in aortic aneurysm disease: PRO.
Cardiol Clin
PUBLISHED: 05-11-2010
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Thoracic aortic aneurysms leading to type A dissections (TAAD) are the major diseases affecting the aorta. A genetic predisposition for TAAD can occur as part of a genetic syndrome. It can be inherited in an autosomal dominant manner with decreased penetrance and variable expression. Genetic heterogeneity for familial TAAD has been demonstrated with the identification of four genes leading to TAAD. Genetic testing for TAAD and the phenotype and management of patients harboring mutations in these genes are addressed in this article.
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Rare copy number variants disrupt genes regulating vascular smooth muscle cell adhesion and contractility in sporadic thoracic aortic aneurysms and dissections.
Am. J. Hum. Genet.
PUBLISHED: 03-08-2010
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Thoracic aortic aneurysms and dissections (TAAD) cause significant morbidity and mortality, but the genetic origins of TAAD remain largely unknown. In a genome-wide analysis of 418 sporadic TAAD cases, we identified 47 copy number variant (CNV) regions that were enriched in or unique to TAAD patients compared to population controls. Gene ontology, expression profiling, and network analysis showed that genes within TAAD CNVs regulate smooth muscle cell adhesion or contractility and interact with the smooth muscle-specific isoforms of ?-actin and ?-myosin, which are known to cause familial TAAD when altered. Enrichment of these gene functions in rare CNVs was replicated in independent cohorts with sporadic TAAD (STAAD, n = 387) and inherited TAAD (FTAAD, n = 88). The overall prevalence of rare CNVs (23%) was significantly increased in FTAAD compared with STAAD patients (Fishers exact test, p = 0.03). Our findings suggest that rare CNVs disrupting smooth muscle adhesion or contraction contribute to both sporadic and familial disease.
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Thoracic aortic disease in tuberous sclerosis complex: molecular pathogenesis and potential therapies in Tsc2+/- mice.
Hum. Mol. Genet.
PUBLISHED: 02-16-2010
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Tuberous sclerosis complex (TSC) is a genetic disorder with pleiotropic manifestations caused by heterozygous mutations in either TSC1 or TSC2. One of the less investigated complications of TSC is the formation of aneurysms of the descending aorta, which are characterized on pathologic examination by smooth muscle cell (SMC) proliferation in the aortic media. SMCs were explanted from Tsc2(+/-) mice to investigate the pathogenesis of aortic aneurysms caused by TSC2 mutations. Tsc2(+/-) SMCs demonstrated increased phosphorylation of mammalian target of rapamycin (mTOR), S6 and p70S6K and increased proliferation rates compared with wild-type (WT) SMCs. Tsc2(+/-) SMCs also had reduced expression of SMC contractile proteins compared with WT SMCs. An inhibitor of mTOR signaling, rapamycin, decreased SMC proliferation and increased contractile protein expression in the Tsc2(+/-) SMCs to levels similar to WT SMCs. Exposure to alpha-elastin fragments also decreased proliferation of Tsc2(+/-) SMCs and increased levels of p27(kip1), but failed to increase expression of contractile proteins. In response to artery injury using a carotid artery ligation model, Tsc2(+/-) mice significantly increased neointima formation compared with the control mice, and the neointima formation was inhibited by treatment with rapamycin. These results demonstrate that Tsc2 haploinsufficiency in SMCs increases proliferation and decreases contractile protein expression and suggest that the increased proliferative potential of the mutant cells may be suppressed in vivo by interaction with elastin. These findings provide insights into the molecular pathogenesis of aortic disease in TSC patients and identify a potential therapeutic target for treatment of this complication of the disease.
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Genetic variants promoting smooth muscle cell proliferation can result in diffuse and diverse vascular diseases: evidence for a hyperplastic vasculomyopathy.
Genet. Med.
PUBLISHED: 02-05-2010
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Genetic predisposition to early onset of occlusive vascular diseases, including coronary artery disease, ischemic stroke, and Moyamoya disease, may represent varying presentations of a common underlying dysregulation of vascular smooth muscle cell proliferation. We discuss mutations in two genes, NF1 and ACTA2, which predispose affected individuals to diffuse and diverse vascular diseases. These patients show evidence of diffuse occlusive disease in multiple arterial beds or even develop seemingly diverse arterial pathologies, ranging from occlusions to arterial aneurysms. We also present the current evidence that both NF1 and ACTA2 mutations promote increased smooth muscle cell proliferation in vitro and in vivo, which leads us to propose that these diffuse and diverse vascular diseases are the outward signs of a more fundamental disease: a hyperplastic vasculomyopathy. We suggest that the concept of a hyperplastic vasculomyopathy offers a new approach not only to identifying mutated genes that lead to vascular diseases but also to counseling and possibly treating patients harboring such mutations. In other words, this framework may offer the opportunity to therapeutically target the inappropriate smooth muscle cell behavior that predisposes to a variety of vascular diseases throughout the arterial system.
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FBN1 mutations in patients with descending thoracic aortic dissections.
Am. J. Med. Genet. A
PUBLISHED: 01-19-2010
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Aortic aneurysm and dissection cause significant morbidity and mortality. There are several known single gene disorders that predispose to isolated aortic disease and eventually aneurysm and dissection. FBN1 mutations are associated with multiple clinical phenotypes, including Marfan syndrome (MFS), MASS phenotype, and familial ectopia lentis, but rarely with isolated aortic aneurysm and dissection. In this report, we describe three patients who presented with primary descending thoracic aortic dissection and who were found to have an FBN1 mutation. None of the patients fulfilled clinical criteria for the diagnosis of MFS, and all had few or none of the skeletal features typical of the condition. Two patients had a history of long-term hypertension, and such a history was suspected in the third patient. These observations suggest that some individuals with FBN1 mutations have significant aortic disease involvement of other systems that is typical of FBN1 mutation-related syndromes. Superimposed risk factors, such as hypertension, may weaken the aortic wall and eventually lead to aortic dissection. Given that the cost continues to decrease, we suggest that diagnostic DNA sequencing for FBN1 mutations in patients with thoracic aortic aneurysms and dissection may be a practical clinical step in evaluating such patients and at-risk family members.
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An adventitial IL-6/MCP1 amplification loop accelerates macrophage-mediated vascular inflammation leading to aortic dissection in mice.
J. Clin. Invest.
PUBLISHED: 09-23-2009
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Vascular inflammation contributes to cardiovascular diseases such as aortic aneurysm and dissection. However, the precise inflammatory pathways involved have not been clearly defined. We have shown here that subcutaneous infusion of Ang II, a vasopressor known to promote vascular inflammation, into older C57BL/6J mice induced aortic production of the proinflammatory cytokine IL-6 and the monocyte chemoattractant MCP-1. Production of these factors occurred predominantly in the tunica adventitia, along with macrophage recruitment, adventitial expansion, and development of thoracic and suprarenal aortic dissections. In contrast, a reduced incidence of dissections was observed after Ang II infusion into mice lacking either IL-6 or the MCP-1 receptor CCR2. Further analysis revealed that Ang II induced CCR2+CD14hiCD11bhiF4/80- macrophage accumulation selectively in aortic dissections and not in aortas from Il6-/- mice. Adoptive transfer of Ccr2+/+ monocytes into Ccr2-/- mice resulted in selective monocyte uptake into the ascending and suprarenal aorta in regions of enhanced ROS stress, with restoration of IL-6 secretion and increased incidence of dissection. In vitro, coculture of monocytes and aortic adventitial fibroblasts produced MCP-1- and IL-6-enriched conditioned medium that promoted differentiation of monocytes into macrophages, induced CD14 and CD11b upregulation, and induced MCP-1 and MMP-9 expression. These results suggest that leukocyte-fibroblast interactions in the aortic adventitia potentiate IL-6 production, inducing local monocyte recruitment and activation, thereby promoting MCP-1 secretion, vascular inflammation, ECM remodeling, and aortic destabilization.
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Acute type A intramural hematoma: analysis of current management strategy.
Circulation
PUBLISHED: 09-16-2009
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Management of acute type A intramural hematoma (IMH) remains controversial, varying from immediate surgery to medical management only. Conversion to typical dissection remains a concern. We analyzed our experience managing acute type A IMH.
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Paucity of skeletal manifestations in Hispanic families with FBN1 mutations.
Eur J Med Genet
PUBLISHED: 08-21-2009
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Marfan syndrome (MFS) is an autosomal dominant condition with pleiotropic manifestations involving the skeletal, ocular, and cardiovascular systems. The diagnosis is based primarily on clinical involvement of these and other systems, referred to as the Ghent criteria. We have identified three Hispanic families from Mexico with cardiovascular and ocular manifestations due to novel FBN1 mutations but with paucity of skeletal features. The largest family, hMFS001, had a frameshift mutation in exon 24 (3075delC) identified as the cause of aortic disease in the family. Assessment of eight affected adults revealed no major skeletal manifestation of MFS. Family hMFS002 had a missense mutation (R1530C) in exon 37. Four members fulfilled the criteria for ocular and cardiovascular phenotype but lacked skeletal manifestations. Family hMFS003 had two consecutive missense FBN1 mutations (C515W and R516G) in exon 12. Eight members fulfilled the ocular criteria for MFS and two members had major cardiovascular manifestations, however none of them met criteria for skeletal system. These data suggest that individuals of Hispanic descent with FBN1 mutations may not manifest skeletal features of the MFS to the same extent as Caucasians. We recommend that echocardiogram, ocular examination and FBN1 molecular testing be considered for any patients with possible MFS even in the absence of skeletal features, including Hispanic patients.
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Valve-sparing and valve-replacing techniques for aortic root replacement in patients with Marfan syndrome: Analysis of early outcome.
J. Thorac. Cardiovasc. Surg.
PUBLISHED: 04-22-2009
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A prospective, international registry study was initiated to provide contemporary comparative data on short-term clinical outcomes after aortic valve-sparing and aortic valve-replacing root operations in patients with Marfan syndrome. The purpose of this initial report is to describe the study design and to compare early outcomes in the first 151 enrolled patients.
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The FBN2 gene: new mutations, locus-specific database (Universal Mutation Database FBN2), and genotype-phenotype correlations.
Hum. Mutat.
PUBLISHED: 04-11-2009
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Congenital contractural arachnodactyly (CCA) is an extremely rare disease, due to mutations in the FBN2 gene encoding fibrillin-2. Another member of the fibrillin family, the FBN1 gene, is involved in a broad phenotypic continuum of connective-tissue disorders including Marfan syndrome. Identifying not only what is in common but also what differentiates these two proteins should enable us to better comprehend their respective functions and better understand the multitude of diseases in which these two genes are involved. In 1995 we created a locus-specific database (LSDB) for FBN1 mutations with the Universal Mutation Database (UMD) tool. To facilitate comparison of identified mutations in these two genes and search for specific functional areas, we created an LSDB for the FBN2 gene: the UMD-FBN2 database. This database lists 26 published and six newly identified mutations that mainly comprise missense and splice-site mutations. Although the number of described FBN2 mutations was low, the frequency of joint dislocation was significantly higher with missense mutations when compared to splice site mutations.
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Sequencing of TGF-beta pathway genes in familial cases of intracranial aneurysm.
Stroke
PUBLISHED: 03-19-2009
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Familial aggregation of intracranial aneurysms (IA) strongly suggests a genetic contribution to pathogenesis. However, genetic risk factors have yet to be defined. For families affected by aortic aneurysms, specific gene variants have been identified, many affecting the receptors to transforming growth factor-beta (TGF-beta). In recent work, we found that aortic and intracranial aneurysms may share a common genetic basis in some families. We hypothesized, therefore, that mutations in TGF-beta receptors might also play a role in IA pathogenesis.
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Valve-sparing and valve-replacing techniques for aortic root replacement in patients with Marfan syndrome: analysis of early outcome.
J. Thorac. Cardiovasc. Surg.
PUBLISHED: 03-05-2009
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A prospective, international registry study was initiated to provide contemporary comparative data on short-term clinical outcomes after aortic valve-sparing and aortic valve-replacing root operations in patients with Marfan syndrome. The purpose of this initial report is to describe the study design and to compare early outcomes in the first 151 enrolled patients.
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Mutations in smooth muscle alpha-actin (ACTA2) cause coronary artery disease, stroke, and Moyamoya disease, along with thoracic aortic disease.
Am. J. Hum. Genet.
PUBLISHED: 02-11-2009
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The vascular smooth muscle cell (SMC)-specific isoform of alpha-actin (ACTA2) is a major component of the contractile apparatus in SMCs located throughout the arterial system. Heterozygous ACTA2 mutations cause familial thoracic aortic aneurysms and dissections (TAAD), but only half of mutation carriers have aortic disease. Linkage analysis and association studies of individuals in 20 families with ACTA2 mutations indicate that mutation carriers can have a diversity of vascular diseases, including premature onset of coronary artery disease (CAD) and premature ischemic strokes (including Moyamoya disease [MMD]), as well as previously defined TAAD. Sequencing of DNA from patients with nonfamilial TAAD and from premature-onset CAD patients independently identified ACTA2 mutations in these patients and premature onset strokes in family members with ACTA2 mutations. Vascular pathology and analysis of explanted SMCs and myofibroblasts from patients harboring ACTA2 suggested that increased proliferation of SMCs contributed to occlusive diseases. These results indicate that heterozygous ACTA2 mutations predispose patients to a variety of diffuse and diverse vascular diseases, including TAAD, premature CAD, ischemic strokes, and MMD. These data demonstrate that diffuse vascular diseases resulting from either occluded or enlarged arteries can be caused by mutations in a single gene and have direct implications for clinical management and research on familial vascular diseases.
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Surgical treatment of patients enrolled in the national registry of genetically triggered thoracic aortic conditions.
Ann. Thorac. Surg.
PUBLISHED: 02-09-2009
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Genetic disorders are an important cause of thoracic aortic aneurysms (TAAs) in young patients. Despite advances in the treatment of genetically triggered TAAs, the optimal syndrome-specific treatment approach remains undefined. We used data from the National Institutes of Health-funded, multicenter National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC) to characterize the contemporary surgical treatment of patients with genetically triggered TAAs.
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Thoracic aortic disease in two patients with juvenile polyposis syndrome and SMAD4 mutations.
Am. J. Med. Genet. A
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Dilation or aneurysm of the ascending aorta can progress to acute aortic dissection (Thoracic Aortic Aneurysms and Aortic Dissections, TAAD). Mutations in genes encoding TGF-?-related proteins (TGFBR1, TGFBR2, FBN1, and SMAD3) cause syndromic and inherited TAAD. SMAD4 mutations are associated with juvenile polyposis syndrome (JPS) and a combined JPS-hereditary hemorrhagic telangiectasia (HHT) known as JPS-HHT. A family with JPS-HHT was reported to have aortic root dilation and mitral valve abnormalities. We report on two patients with JPS-HHT with SMAD4 mutations associated with thoracic aortic disease. The first patient, an 11-year-old boy without Marfan syndrome features, had JPS and an apparently de novo SMAD4 mutation (c.1340_1367dup28). Echocardiography showed mild dilation of the aortic annulus and aortic root, and mild dilation of the sinotubular junction and ascending aorta. Computed tomography confirmed aortic dilation and showed small pulmonary arteriovenous malformations (PAVM). The second patient, a 34-year-old woman with colonic polyposis, HHT, and features of Marfan syndrome, had a SMAD4 mutation (c.1245_1248delCAGA). Echocardiography showed mild aortic root dilation. She also had PAVM and hepatic focal nodular hyperplasia. Her family history was significant for polyposis, HHT, thoracic aortic aneurysm, and dissection and skeletal features of Marfan syndrome in her father. These two cases confirm the association of thoracic aortic disease with JPS-HHT resulting from SMAD4 mutations. We propose that the thoracic aorta should be screened in patients with SMAD4 mutations to prevent untimely death from dissection. This report also confirms that SMAD4 mutations predispose to TAAD.
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Diabetes and reduced risk for thoracic aortic aneurysms and dissections: a nationwide case-control study.
J Am Heart Assoc
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Vascular diseases are the principal causes of death and disability in people with diabetes. At the same time, studies suggest a protective role of diabetes in the development of abdominal aortic aneurysms. We sought to determine whether diabetes is associated with decreased hospitalization due to thoracic aortic aneurysms and dissections (TAAD).
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A novel distinctive cerebrovascular phenotype is associated with heterozygous Arg179 ACTA2 mutations.
Brain
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Mutations in the ACTA2 gene lead to diffuse and diverse vascular diseases; the Arg179His mutation is associated with an early onset severe phenotype due to global smooth muscle dysfunction. Cerebrovascular disease associated with ACTA2 mutations has been likened to moyamoya disease, but appears to have distinctive features. This study involved the analysis of neuroimaging of 13 patients with heterozygous missense mutations in ACTA2 disrupting Arg179. All patients had persistent ductus arteriosus and congenital mydriasis, and variable presentation of pulmonary hypertension, bladder and gastrointestinal problems associated with this mutation. Distinctive cerebrovascular features were dilatation of proximal internal carotid artery, occlusive disease of terminal internal carotid artery, an abnormally straight course of intracranial arteries, and absent basal moyamoya collaterals. Patterns of brain injury supported both large and small vessel disease. Key differences from moyamoya disease were more widespread arteriopathy, the combination of arterial ectasia and stenosis and, importantly, absence of the typical basal moyamoya collaterals. Evaluation of previously published cases suggests some of these features are also seen in the ACTA2 mutations disrupting Arg258. The observation that transition from dilated to normal/stenotic arterial calibre coincides with where the internal carotid artery changes from an elastic to muscular artery supports the hypothesis that abnormal smooth muscle cell proliferation caused by ACTA2 mutations is modulated by arterial wall components. Patients with persistent ductus arteriosus or congenital mydriasis with a label of moyamoya should be re-evaluated to ensure the distinctive neuroimaging features of an ACTA2 mutation have not been overlooked. This diagnosis has prognostic and genetic implications, and mandates surveillance of other organ systems, in particular the aorta, to prevent life-threatening aortic dissection.
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Eye features in three Danish patients with multisystemic smooth muscle dysfunction syndrome.
Br J Ophthalmol
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A de novo mutation of the ACTA2 gene encoding the smooth muscle cell ?-actin has been established in patients with multisystemic smooth muscle dysfunction syndrome associated with patent ductus arteriosus and mydriasis present at birth.
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TGFB2 mutations cause familial thoracic aortic aneurysms and dissections associated with mild systemic features of Marfan syndrome.
Nat. Genet.
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A predisposition for thoracic aortic aneurysms leading to acute aortic dissections can be inherited in families in an autosomal dominant manner. Genome-wide linkage analysis of two large unrelated families with thoracic aortic disease followed by whole-exome sequencing of affected relatives identified causative mutations in TGFB2. These mutations-a frameshift mutation in exon 6 and a nonsense mutation in exon 4-segregated with disease with a combined logarithm of odds (LOD) score of 7.7. Sanger sequencing of 276 probands from families with inherited thoracic aortic disease identified 2 additional TGFB2 mutations. TGFB2 encodes transforming growth factor (TGF)-?2, and the mutations are predicted to cause haploinsufficiency for TGFB2; however, aortic tissue from cases paradoxically shows increased TGF-?2 expression and immunostaining. Thus, haploinsufficiency for TGFB2 predisposes to thoracic aortic disease, suggesting that the initial pathway driving disease is decreased cellular TGF-?2 levels leading to a secondary increase in TGF-?2 production in the diseased aorta.
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Rare, nonsynonymous variant in the smooth muscle-specific isoform of myosin heavy chain, MYH11, R247C, alters force generation in the aorta and phenotype of smooth muscle cells.
Circ. Res.
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Mutations in myosin heavy chain (MYH11) cause autosomal dominant inheritance of thoracic aortic aneurysms and dissections. At the same time, rare, nonsynonymous variants in MYH11 that are predicted to disrupt protein function but do not cause inherited aortic disease are common in the general population and the vascular disease risk associated with these variants is unknown.
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MicroRNAs, fibrotic remodeling, and aortic aneurysms.
J. Clin. Invest.
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Aortic aneurysms are a common clinical condition that can cause death due to aortic dissection or rupture. The association between aortic aneurysm pathogenesis and altered TGF-? signaling has been the subject of numerous investigations. Recently, a TGF-?-responsive microRNA (miR), miR-29, has been identified to play a role in cellular phenotypic modulation during aortic development and aging. In this issue of JCI, Maegdefessel and colleagues demonstrate that decreasing the levels of miR-29b in the aortic wall can attenuate aortic aneurysm progression in two different mouse models of abdominal aortic aneurysms. This study highlights the relevance of miR-29b in aortic disease but also raises questions about its specific role.
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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.