Clinical outcome and genotype in patients with hereditary multiple exostoses.

Hereditary multiple exostoses (HME) is an autosomal dominant skeletal disorder with a wide spectrum of clinical manifestations. In 52 out of 60 individuals from HME+ families, exostoses became clinically apparent. In this study, the clinical and radiological outcome of these 52 HME patients (19 families) was investigated by medical history, clinical examination, and radiographs. In addition to correlating phenotype with genotype, a linkage/exclusion analysis was performed in 35 HME patients. We found several correlations between HME genes (EXT1, EXT2) and phenotype. Compared to EXT2-linkage, female individuals with EXT1-linkage were smaller in stature. Patients with EXT1-linkage and patients with undetermined linkage (EXT?) were more severely affected, underwent more surgeries, and showed a higher number of exostoses at follow-up. Moreover, we found an increased phenotype risk for limb shortening for EXT1- and EXT?-linkage. This study corresponds to data of other investigators who showed that EXT1 mutations are associated with a more severe phenotype than other EXT forms. (c) 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1541-1551, 2007.