Familial spondyloepiphyseal dysplasia tarda, brachydactyly, and precocious osteoarthritis associated with an arginine 75-->cysteine mutation in the procollagen type II gene in a kindred of Chiloe Islanders. I. Clinical, radiographic, and pathologic findings.

OBJECTIVE: To characterize a kindred of Chiloe Islanders with spondyloepiphyseal dysplasia tarda (SEDT), brachydactyly, precocious osteoarthritis (OA), and intraarticular calcification. METHODS: Sixteen family members underwent a complete physical examination, anthropometric measurements, radiographic studies of the spine and peripheral joints, and analysis of the type II procollagen gene (COL2A1). RESULTS: Seven family members presented with SEDT, brachydactyly, precocious OA, and periarticular calcification while 2 others had the same syndrome but without brachydactyly. The inheritance was autosomal dominant, and the disease cosegregated with a base substitution in the COL2A1 gene. CONCLUSION: The syndrome o SEDT, precocious OA, and brachydactyly in a kindred of Chiloe Islanders is associated with a point mutation in 1 allele of the COL2A1 gene. The relationship of this type of SEDT to familial calcium pyrophosphate dihydrate deposition disease and idiopathic hip dysplasia, both endemic in Chiloe Islanders, needs to be further investigated.