In comparison, a type II collagenopathy involving a single organ system is the COL2A1-related osteoarthritis with mild chondrodysplasia (OSCDP) that is characterized by isolated skeletal/joint involvement, i.e. OA of hips, knees, shoulders, wrists, hands, joint stiffness, spine abnormalities (irregular endplates, mild platyspondyly, anterior wedging) and manifestations of the hands (enlarged MCP, PIP and DIP joints, Heberden's nodes)3,4. This evidence concerns the gene COL2A1 and mild spondyloepiphyseal dysplasia due to COL2A1 mutation with early-onset osteoarthritis.