Baldwin et al. (1995) described a 6-generation New England family (family BU91) in which many members had early-onset CPPDD and severe degenerative osteoarthritis. Onset occurred between ages 25 and 40 years and males and females were equally affected. ... Baldwin et al. (1995) described a 6-generation New England family (family BU91) in which many members had early-onset CPPDD and severe degenerative osteoarthritis. Onset occurred between ages 25 and 40 years and males and females were equally affected. The authors stated that it was unclear whether the primary event causing the disease was deposition of calcium-containing crystals in joint tissue (caused by a defect in a 'CPPDD gene') that progressed to severe degenerative osteoarthritis or whether degenerative changes in cartilage (resulting from mutation in an 'osteoarthritis gene') enhanced deposition of calcium-containing crystals.