A severely disabling disease with manifestation of progressive groin pain, a limping gait, leg length discrepancy, collapse of the subchondral bone, limitation of hip function and eventual degeneration of the hip joint requiring total hip arthroplasty. Familial forms appear to be very rare, with only three families identified so far. Age of onset in these familial cases ranges from 15-48. Transmission in familial cases is autosomal dominant and mutations in the type II collagen gene (COL2A1) have been detected in affected family members. [from
SNOMEDCT_US]