Molecular analysis of IDS gene and prenatal diagnosis in a Chinese family with mucopolysaccharidosis type II

Objective Mucopolysaccharidosis type II (MPSII) is a lethal, X-linked recessive disorder caused by mutation of iduronate-2-sulfatase (IDS) gene. Up to now there is no really effective treatment for this disorder, therefore it is important to provide an accurate genetic diagnosis and prenatal diagnosis for the MPSII families. In this study, we identify the pathogenic mutation in a Chinese family with MPSII. Method The 8 years old male proband from a Chinese family was clinically diagnosed with MPSII. There are other 4 patients with similar phenotypes in the family who died at 9, 11, 7 and 10 years of age, respectively. Mutation analysis was carried out by polymerase chain reaction and direct sequencing of all exons and exon/intron boundaries of IDS gene. Denaturing high performance liquid chromatography (DHPLC) analysis was performed to screen the unknown variations of IDS gene in 100 unrelated control males. Result Two allelic variants of exon 5 (c.684A > G) and exon 6 (c.851C > T) and a nonsense mutation of exon 7 (c.892C > T) were detected in IDS gene of the proband. Heterozygous mutations c.684A > G, c.851C > T and c.892C > T were detected in both proband's mother and maternal grandmother. The unknown variations of c.684A > G and c.851C > T were not found in the 100 unrelated control males. The male fetus (IV11) inherited the same mutation of IDS gene as the proband. Conclusion Mutation c.892C > T of IDS gene causes MPSII in this family and prenatal diagnosis in one affected fetus was achieved.