Familial Avascular Necrosis of Femoral Head, also known as familial osteonecrosis of the femoral head, is related to osteonecrosis and avascular necrosis. An important gene associated with Familial Avascular Necrosis of Femoral Head is COL2A1 (Collagen Type II Alpha 1 Chain). Affiliated tissues include bone, and related phenotypes are groin pain and abnormal femoral neck/head morphology