Molecular studies of achondroplasia.

Abstract

Achondroplasia (ACH) is the most frequent form of short-limbed dwarfism, caused by mutations in the FGFR3 gene. It follows an autosomal dominant inheritance, though most cases are sporadic. The molecular techniques are the only available methods to confirm the diagnosis of a skeletal dysplasia. Clinical and radiological features are only suggestive and not confirmatory. The present study was conducted to find out how often the clinical diagnosis of achondroplasia is verified on molecular studies. From 1998 through 2007, we carried out molecular analysis for the two common mutations in the FGFR3 gene in 130 cases clinically suspected to have ACH. A diagnostic mutation was identified in 53 (40.8%) cases. The common mutation (1138G>A) was present in 50 (94.7%) of the positive cases, while the rare 1138 G>C substitution was found in three (5.3%). This study shows that confirmation of clinical diagnosis of ACH by molecular genetic testing is essential to distinguish it from other skeletal dysplasias, to plan therapeutic options, and to offer genetic counseling. Management (medical and surgical) in patients confirmed to have ACH, is briefly discussed.