123 MOLECULAR GENETIC ANALYSIS IN HUNTER DISEASE

Abstract

Clinical and biochemical studies have revealed a great phenotypic variability in mucopolysaccharidosis type II (Hunter disease), probably due to different mutations in the IDS gene that has been localized in Xq28. Using a cDNA probe containing almost the entire coding region of the human IDS gene, we performed a molecular analysis on 7 patients with Hunter disease. In one patient, a complete deletion of the IDS coding sequences was found. Another patient had structural alterations of the IDS gene including a partial deletion. In 5 patients, however, after restriction digestion of the DNA by PstI and TaqI and Southern hybridization with the IDS cDNA, the audiographic patterns obtained were similar to those found in controls. These patients may probably have small deletions or point mutations in the IDS gene. Genotype analysis offers now the possibility to detect carrier among females at risk and to perform prenatal diagnosis in this X-linked disorder.