COL11A1 encodes the α1 chain of type XI collagen, a minor fibrillar collagen critical for connective tissue organization. Functionally, COL11A1 plays an important role in fibrillogenesis by controlling lateral growth of collagen II fibrils, contributing to extracellular matrix structural integrity and tensile strength 1. The gene is expressed by specific fibroblast subpopulations involved in connective tissue differentiation and matrix deposition 1. Pathogenic COL11A1 variants predominantly exert dominant-negative effects rather than haploinsufficiency, making the mutation location and type critical determinants of disease severity 2. COL11A1 mutations are associated with multiple genetic disorders including Stickler syndrome (dominant and recessive forms), Marshall syndrome, and autosomal dominant deafness-37 34. In Stickler syndrome, COL11A1 mutations specifically cause vitreo-retinal features, sensorineural hearing loss, cleft palate, and premature arthritis 24. Beyond genetic disease, COL11A1 is upregulated in pathological fibrosis contexts, including systemic sclerosis and cancer-associated desmoplasia, where it serves as a biomarker of activated stromal cells and correlates with disease progression and metastatic potential 56. These findings suggest COL11A1 expression distinguishes disease-relevant fibroblast populations in both inherited connective tissue disorders and acquired fibrotic diseases.