Approximately 20 % of individuals with Parkinsons disease (PD) report a positive family history. Yet, a large portion of causal and disease-modifying variants is still unknown. We used exome sequencing in two affected individuals from a family with late-onset PD to identify 15 potentially causal variants. Segregation analysis and frequency assessment in 862 PD cases and 1,014 ethnically matched controls highlighted variants in EEF1D and LRRK1 as the best candidates. Mutation screening of the coding regions of these genes in 862 cases and 1,014 controls revealed several novel non-synonymous variants in both genes in cases and controls. An in silico multi-model bioinformatics analysis was used to prioritize identified variants in LRRK1 for functional follow-up. However, protein expression, subcellular localization, and cell viability were not affected by the identified variants. Although it has yet to be proven conclusively that variants in LRRK1 are indeed causative of PD, our data strengthen a possible role for LRRK1 in addition to LRRK2 in the genetic underpinnings of PD but, at the same time, highlight the difficulties encountered in the study of rare variants identified by next-generation sequencing in diseases with autosomal dominant or complex patterns of inheritance.
Genetic variation in the glucocerebrosidase (GBA) gene is strongly associated with Parkinsons disease (PD). Transport of glucocerebrosidase to the lysosome involves the protein encoded by the SCARB2 gene. An association between the common SNP rs6812193, upstream of SCARB2, and PD has been reported previously. The role of exonic variants in the SCARB2 gene in PD has not been examined.
Approximately 20% of individuals with Parkinsons disease (PD) report a positive family history. Yet, a large portion of causal and disease-modifying variants is still unknown. We used exome sequencing in two affected individuals from a family with late-onset familial PD followed by frequency assessment in 975 PD cases and 1014 ethnically-matched controls and linkage analysis to identify potentially causal variants. Based on the predicted penetrance and the frequencies, a variant in PLXNA4 proved to be the best candidate and PLXNA4 was screened for additional variants in 862 PD cases and 940 controls, revealing an excess of rare non-synonymous coding variants in PLXNA4 in individuals with PD. Although we cannot conclude that the variant in PLXNA4 is indeed the causative variant, these findings are interesting in the light of a surfacing role of axonal guidance mechanisms in neurodegenerative disorders but, at the same time, highlight the difficulties encountered in the study of rare variants identified by next-generation sequencing in diseases with autosomal dominant or complex patterns of inheritance.
To identify rare causal variants in late-onset Parkinson disease (PD), we investigated an Austrian family with 16 affected individuals by exome sequencing. We found a missense mutation, c.1858G>A (p.Asp620Asn), in the VPS35 gene in all seven affected family members who are alive. By screening additional PD cases, we saw the same variant cosegregating with the disease in an autosomal-dominant mode with high but incomplete penetrance in two further families with five and ten affected members, respectively. The mean age of onset in the affected individuals was 53 years. Genotyping showed that the shared haplotype extends across 65 kilobases around VPS35. Screening the entire VPS35 coding sequence in an additional 860 cases and 1014 controls revealed six further nonsynonymous missense variants. Three were only present in cases, two were only present in controls, and one was present in cases and controls. The familial mutation p.Asp620Asn and a further variant, c.1570C>T (p.Arg524Trp), detected in a sporadic PD case were predicted to be damaging by sequence-based and molecular-dynamics analyses. VPS35 is a component of the retromer complex and mediates retrograde transport between endosomes and the trans-Golgi network, and it has recently been found to be involved in Alzheimer disease.
We conducted an open, 16-week study on the efficacy of memantine on behavioral disturbances and psychotic symptoms in moderate to moderately severe Alzheimer s disease in daily routine. Fifty-three patients of 20 outpatient centers in Austria were recruited. The Neuropsychiatric Inventory (NPI) was defined as main outcome measure. After 16 weeks the total NPI score improved by 4,6 points (p<0.01). The caregiver distress score was also significantly reduced. The most pronounced improvements were seen in the NPI components depression (-24,6%), aberrant motor behavior (-16,9%), agitation/agression, fear, apathy, disinhibition and disturbances in appetite and eating behavior (-11,3%, each). Our naturalistic study is in line with the results of controlled trials in moderate and severe Alzheimer dementia stages. Controlled clinical trials which have behavioral disturbances and psychotic symptoms as primary endpoint are needed to define the true potential of memantine in mild dementia stages.
Semiquantitative evaluation of tracer uptake in basal ganglia is superior to visual assessment of images in dopamine transporter (DAT) scintigraphy especially in follow-up of the patients. Manual drawing of regions of interest (ROIs) in two-dimensional (2D) transaxial slices of the single photon emission computed tomography (SPECT) datasets leads to a large inter- and intra-reader variability, while being time consuming. Our aim was to investigate a technique that extracts 3D ROIs in a fully automated fashion and thus might provide reproducible user-independent results allowing better follow-up control and large-scale clinical studies.
A clinical overlap between Parkinsons disease (PD) and essential tremor (ET) has prompted a discussion whether these conditions share common genetic susceptibility factors. Recently, the first genome-wide association study in ET revealed a significant association with a variant in the LINGO1 gene. LINGO1 has also been demonstrated to play a role in the survival of dopaminergic neurons in an animal model of PD, and therefore constitutes a potential candidate gene for PD. In this study, SNPs rs9652490, rs11856808, and rs7177008 of LINGO1 were genotyped in a total of 694 Austrian subjects (349 PD, 345 controls). No association could be found between genotype or allele counts and PD. Neither did a subgroup analysis in tremor-dominant patients with PD reveal a significant association. This study on LINGO1-variants in PD argues against a major role of LINGO1 gene variations for PD.
We report of a 46-year-old female patient with cryptogen organizing pneumonia preceding the rare SRP positive necrotising myositis without cardiac involvement and no sign of dysphagia. Myositis showed full regression without oral immune suppression but with extracorporeal treatment, performed as a combined therapy of plasmaexchange and immunoadsorption. After 33-month of treatment, anti-SRP antibodies were not detectable any more.
The GIGYF2 (Grb10-Interacting GYF Protein-2) gene has recently been proposed to be the responsible gene for the PARK11 locus. Ten different putative pathogenic variants were identified in cohorts of Parkinsons disease (PD) patients from Italy and France. Among these variants Asn56Ser and Asn457Thr were found repeatedly. In the present study we screened 669 PD patients (predominantly of central European origin) and 1051 control individuals for the presence of these two variants. Asn56Ser was found in one patient with a positive family history of the disease and in one control individual. The affected sister of the patient did not carry this variant. Asn457Thr was found in one patient, who was exceptional for his Egyptian origin and in three control individuals. This variant was not found in 50 control individuals from Egypt. We conclude that neither of these two variants plays a major role in the pathogenesis of PD in our study population.
Recently, mutations in eukaryotic translation initiation factor 4G1 (EIF4G1) were reported as a rare cause of familial Parkinsons disease (PD). We screened the 33 exons of EIF4G1 by high-resolution melting curve analysis for variants in our Central European cohort of 376 PD cases. Variant frequency was assessed in a total of 975 PD cases and 1,014 general population controls. Eight novel nonsynonymous and four synonymous variants were identified. In our cohort, novel and previously identified nonsynonymous variants were very rare. Although it is possible that our general population controls also comprise individuals who have or could develop PD in the future, the presence of the original mutation (EIF4G1 p.Arg1205 His) in three controls only, raises questions about the causality of this variant with regard to PD.
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