New Genetic Analysis in Cases with Hunter Syndrome in Whom IDS Gene Mutations Could Not Be Detected: RNA Sequencing

Mucopolysaccharidosis-II (MPSII) is diagnosed based on a deficiency in iduronate 2-sulfatase enzyme activity. Detection of a hemizygous pathogenic variant in the iduronate 2-sulfatase (IDS) gene confirms the diagnosis in a male proband.

We report a five-year-old boy with MPSII in whom no mutation was detected in the IDS gene by next-generation sequencing (Miseq-Illumina) covering the coding regions of the gene. Therefore, we tried to detect the mutation in the IDS gene using RNA sequencing that has recently been used.

In some diseases diagnosed by clinical and biochemical methods, mutations cannot be detected even with advanced genetic methods, such as next-generation sequencing. In these cases, we emphasize that mutations should be investigated using other methods, including RNA sequencing.