The osteopetroses are a heterogeneous group of disorders characterised by generalised bony sclerosis. The autosomal dominant form usually has a "benign" prognosis, in contrast to the "malignant" course of the autosomal recessive variety. In this paper we describe a kindred in which the phenotypic spectrum varied from an asymptomatic condition in adults to a severely affected infant, presenting with anaemia, hepatosplenomegaly, hydrocephalus and blindness. The findings in this family are reported and discussed to elucidate further the possible genetic heterogeneity in autosomal dominant osteopetrosis.