COL11A2 encodes the alpha-2 chain of collagen type XI, a fibrillar collagen essential for skeletal development and extracellular matrix organization. The protein plays a critical role in controlling lateral growth of collagen II fibrils during fibrillogenesis, contributing to the tensile strength of connective tissues 1. COL11A2 is expressed in cartilage and other tissues, functioning as a structural component of the extracellular matrix 2. Pathogenic COL11A2 variants cause hereditary connective tissue disorders with diverse phenotypes. Loss-of-function mutations underlie vertebral malformations and congenital scoliosis through disruption of vertebral development; zebrafish studies demonstrate that col11a2 mutations produce vertebral fusions due to mineralization across intervertebral segments, and patient-derived missense variants fail to rescue this phenotype 3. COL11A2 mutations are associated with non-syndromic hearing loss (4% of autosomal-dominant cases in Europe) 4, Stickler syndrome without ocular involvement 2, and skeletal dysplasias presenting with growth retardation 5. A COL11A2 genetic variant (rs1799907) shows significant association with rotator cuff tendinopathy in young athletes 6. Clinically, COL11A2 mutation detection via genetic testing aids in diagnosis of skeletal abnormalities and hearing impairment, enabling appropriate genetic counseling and management strategies for affected families 1, 7.