Decreased bone mineral density in HLA-B27 positive members of a family with osteogenesis imperfecta.

We describe a family in which several members had osteogenesis imperfecta (OI) and/or were positive for HLA-B27. The proband, who had ankylosing spondylitis and OI, had severe osteoporosis with fractures continuing to occur in the late teens. Bone mineral density measurements in 5 family members and the proband, revealed more severe osteoporosis in those with positive HLA-B27.