Mutations in collagen genes cause perturbances in the connective tissue according to the specific expression of the respective collagen. Several collagenopathies affect the musculoskeletal system therefore being important to rheumatologists.
Type II collagen is key protein for articular cartilage integrity but is also present in the vitreous, the inner ear and the nucleus pulposus. Mutations in the type II collagen gene (COL2A1) have been identified in patients with various clinical syndromes and are now grouped together as type II collagenopathies. The most common type II collagenopathy is Stickler syndrome type 1 caused by truncating mutations. Stickler Syndrome is characterized by short stature due to chondrodysplasia, distinct facial abnormalities (e.g. cleft palate, midfacial hypoplasia), ophthalmologic manifestations (e.g. myopia, cataract), sensineural hearing loss as well as spinal manifestations (scoliosis, platyspondyly).
Premature osteoarthritis (OA) is typically present in type II collagenopathies. Localization, severity and disease onset in these patients vary according to the disease-causing mutation. OA is usually rapidly progressive frequently necessitating joint replacement surgery. Extra-articular features such as sensineural hearing loss may be absent or clinically mild. Considering the inheritance of the mutation, early identification enables lifestyle modification while causal treatment is unfortunately currently not available. Moreover, a correct diagnosis allows genetic counselling for these usually autosomal- dominant inherited syndromes.
Disclosure of Interest None Declared