In this video, a spinal and bulbar muscular atrophy or SBMA-affected mouse undergoes tail vein injection of recombinant AAV (Adeno-associated vectors) vectors carrying a plasmid encoding therapeutic microRNA. The vector produces microRNA that binds to mutant AR (Androgen receptor)-mRNA (messenger ribonucleic acid), triggering its degradation. This reduces toxic protein accumulation and helps to improve neuromuscular function.