Hereditary multiple exostoses. Report of a family.

In a family with hereditary multiple exostoses (diaphyseal aclasis), six generations are known to have been affected. Thirty-three of 85 family members have had the disorder. This condition affects the long bones, pelvis, scapulae, and ribs, and the exostoses continue to enlarge until epiphyseal fusion occurs. Associated deformities, including short stature and malformations of the wrist and ankle, were found in 72%. Fifty percent of affected individuals were moderately or severely handicapped; women and men were affected with equal severity. Exostoses were usually noted by two years and always by five years of age. Hereditary multiple exostoses is inherited as an autosomal dominant condition and is inherited as an autosomal dominant condition and in this familial study the gene showed 93% penetrance. Only one individual appeared clinically normal but nevertheless transmitted the gene to offspring. Red cell antigens, enzymes, and serum enzymes were studied, but none were positive for linkage to the gene for this disease. The frequency of sarcomatous change varies between 3% and 25% in reports in the literature, but no cases occurred in six generations of this family.