Clinical experience of replacing enzyme replacement therapy in a patient with mucopolysaccharidosis type II

Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is an inherited chronic progressive lysosomal disease associated with recessive X-linked inheritance. MPS II is classified as an orphan disease and occurs at a rate of 1.3 per 100,000 white boys. Hunter syndrome is the most common type of mucopolysaccharidosis, accounting for about 50% of MPS types. The disease’s pathogenesis is based on a violation of the stepwise cleavage of glycosaminoglycans (GAG) — heparansulfate and dermatansulfate caused by a deficiency of the iduronate-2-sulfatase enzyme encoded by the  IDS  gene. The existing deficiency or complete absence of iduronate-2-sulfatase leads to a violation of the final stage of glycosaminoglycan catabolism and the accumulation heparansulfate and dermatansulfate in all organs and tissues. Currently, there are two drugs registered in the Russian Federation for pathogenetic enzyme replacement therapy of MPS: idursulfase and idursulfase beta. This refers to the expansion of the therapeutic options for Hunter syndrome patients in the event of severe adverse events. It allows choosing the treatment regimen that will be optimal for the patient and will significantly improve the quality of life. In this article, the authors share their own experience of changing enzyme replacement therapy in an MPS II child patient.