Novel variations in Exon 4 of the iduronate 2-sulfatase gene in six Indonesian patients with mucopolysaccharidosis type II

Mucopolysaccharidosis type II (MPS II) is an X-linked lysosomal storage disorder caused by the inability to produce iduronate 2-sulfatase (IDS). We genotyped exon 4 of the IDS gene in Indonesian patients with MPS II. To detect IDS gene mutations, DNA samples from 6 patients with MPS II and 49 normal individuals were analyzed with direct sequencing of exon 4. One novel mutation (c.489G>A) was identified in four of six patients. Protein analysis of these mutations revealed no amino acid sequence changes (silent mutation). Another 20 variations were found in normal individuals, including missense, nonsense, and silent mutations. The discovery of this novel mutation provides new mutational data for MPS II, whereas the identified variations strengthen the single nucleotide polymorphism database for the IDS gene. These mutation and variation data should be useful for identifying biomarkers for diagnosing MPS II.