Mucopolysaccharidosis type II (Hunter syndrome): Case study

The paper presents clinical and laboratory characteristics of an orphan disease – mucopolysaccharidosis type 2. The aim of the paper is to demonstrate a clinical case of Hunter syndrome caused by a mutation in the IDS gene. Materials and Methods. Anamnestic, clinical and analytical methods were used during the trial. The authors analyzed patients’ medical history, the results of clinical, laboratory and molecular genetic studies. Results. At the age of 6 months, the child was suspected of having a lysosomal storage disease. The diagnosis was confirmed at the age of 7 months: increased concentration of glycosaminoglycans in urine and decreased activity of iduronate sulfatase were detected. Direct automated sequencing was used for the complete analysis of the IDS gene. The results confirmed the diagnosis of “Hunter disease (OMIM#309900) (NM 000202.8), X-linked recessive type of inheritance”. In exon 7 of the gene, we detected a variant of the nucleotide sequence c.1000G>T (p.Asp334Tyr) in a hemizygous state, described in the HGMD (Human Gene Mutation Database) as pathogenic (CM141183). Conclusion. The clinical example demonstrates that it is possible to diagnose the disease in newborns despite the heterogeneity of the clinical phenotype in Hunter syndrome. Early diagnosis and timely enzyme replacement therapy slow down or even prevent the development of irreversible manifestations of the disease and, therefore, change the natural course of mucopolysaccharidosis type 2, improving patient's quality of life. The analysis of clinical cases is useful primarily for the practical pediatric community. Increasing awareness of MPS type 2 among specialists is a significant factor for early diagnosis and timely treatment. It helps both to prevent disease progression and to determine prognostic aspects.