Abstract
BackgroundMucopolysaccharidosis type II (MPS II; Hunter syndrome) is an X-linked multisystem disorder characterized by glycosaminoglycan (GAG) accumulation, caused by a deficiency of iduronate-2-sulfatase (I2S). Enzyme replacement therapy (ERT) with recombinant idursulfase (IDS), the standard of care, was started in the Philippines in 2017. This study reviewed the clinical outcomes in idursulfase-treated and untreated Filipino MPS II patients who were included in the local Lysosomal Storage Disease (LSD) registry of the Institute of Human Genetics-National Institutes of Health (IHG-NIH) from January 1999 to December 2019.MethodsA retrospective audit of records of MPS II patients listed in the registry was done. Qualified patients were divided into two cohorts: idursulfase-treated group (patients on enzyme replacement therapy, ERT, for ≥ 6 months) and untreated group. Baseline characteristics, including demographic data, biochemical results, neurocognitive classification, respiratory involvement, mortality, and adverse events, were recorded. Height, weight, cardiac pathology, liver and spleen sizes, six-minute walking test (6MWT), joint mobility, were determined at baseline and at year 1 and 2 of follow up.ResultsForty male patients were included in this review, with only 8 receiving ERT since 2017. The mean age at diagnosis was 6.99 years (SD 4.15; 0.75–20) and mean age at start of ERT was 14.03 years (SD 7.1; 4–21.5), more delayed than previous reports. Eighty percent have early progressive phenotype which was higher than reported average. The early growth pattern differed in our Filipino cohort, but was followed by the expected slowed growth in later years. Improvements in the following endpoints were observed in the treated cohort: height and weight, cardiac disease, liver and spleen sizes, and joint mobility. There were also positive effects on respiratory involvement and mortality rate. Adverse events were consistent with previous reports.ConclusionsERT is generally well tolerated and effective in reducing GAG storage and improving clinical endpoints among our Filipino MPS II patients. In untreated patients, typical disease progression was observed.
Highlights
Mucopolysaccharidosis type II (MPS II; known as Hunter syndrome) is an X-linked multisystem disorder characterized by glycosaminoglycan (GAG) accumulation, caused by a deficiency of iduronate-2-sulfatase (I2S) [1]
Long-term follow up of these patients will give a more comprehensive look into its disease progression. This is a retrospective descriptive study of MPS II patients diagnosed at the Philippine General Hospital (PGH), University of the Philippines Manila (UPM) and/or at the Institute of Human Genetics-National Institutes of Health (IHG-NIH) who were subsequently listed in the Lysosomal Storage Disease (LSD) Registry from January 1999 to December 2019
As of December 2019, there were 59 Hunter syndrome patients listed in the Philippine LSD Registry, 40 of whom fulfilled the inclusion criteria
Summary
Mucopolysaccharidosis type II (MPS II; known as Hunter syndrome) is an X-linked multisystem disorder characterized by glycosaminoglycan (GAG) accumulation, caused by a deficiency of iduronate-2-sulfatase (I2S) [1]. The enzyme deficiency in MPS II leads to primary accumulation of dermatan sulfate (DS) and heparan sulfate (HS) [2] The buildup of these GAGs accounts for heterogenous somatic and neurologic manifestations of the disease [3]. Phenotypes are designated as "slowly progressive" or "early progressive", depending on the presence or absence of CNS involvement, respectively [1] In those with early progressive disease, there is progressive cognitive deterioration, progressive airway and cardiac disease that usually result in death in the first or second decade of life.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
