COL6A3 encodes the alpha 3 chain of collagen type VI, which forms trimeric complexes that serve as structural components of the extracellular matrix 1. The protein functions as a cell-binding protein and provides mechanical support while exerting cytoprotective functions including inhibition of apoptosis and oxidative damage 1. COL6A3 plays important roles in muscle organ development and is expressed in disease-relevant tissues including musculoskeletal system 1. Mutations in COL6A3 cause congenital muscular disorders including Ullrich congenital muscular dystrophy, Bethlem myopathy, and myosclerosis myopathy, which present with muscle wasting, weakness, joint contractures, and respiratory compromise 1. COL6A3 variants are among the most common causes of identified muscle disorders in diagnostic sequencing panels 2. Beyond muscle disease, COL6A3 has emerging roles in other pathological processes. The carboxyl terminus product endotrophin mediates obesity's effects on coronary artery disease risk 3. COL6A3 expression is associated with sleep-related traits including chr2 4 and serves as a prognostic biomarker in various cancers including undifferentiated pleomorphic sarcoma 5. In glioblastoma, COL6A3+ tumor-associated fibroblasts contribute to treatment resistance and vascular fibrosis 6.