Clinical characteristics and analysis of IDS gene variant in a child with mucopolysaccharidosis type Ⅱ

Abstract

To summarize the clinical features, laboratory examination and genetic analysis of a patient with mucopolysaccharidosis type Ⅱ (MPS Ⅱ). Clinical manifestations, results of urine glycosaminoglycans (GAGs) and dermatan sulfate assay, metabolites related to MPS in peripheral blood leukocytes were analyzed. Meanwhile, the child and his mother were subjected to next-generation sequencing and Sanger sequencing. The boy has presented with global development delay, coarse facies, frequent upper-respiratory infections, hearing loss, indirect inguinal hernia, hepatosplenomegaly, and skeletal deformities. His urine GAGs were significantly elevated, and the urinary dermatan sulfate (DS) was positive. Meanwhile, the activity of idose-2-sulfatase was extremely reduced. The patient was found to harbor a hemizygote c.676C>G (p. His226Asp) missense variant in exon 5 of IDS gene, for which his mother was heterozygous. The novel c.676C>G variant of the IDS gene probably underlay the MPS Ⅱ in this child. Genetic testing combined with enzymatic analysis can enable effective diagnosis and classification of MPS.