Development of screening and diagnostic assay for mucopolysaccharidosis type II

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K08958
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Laboratory medicine
• Research Institution: National Center for Child Health and Development
• Principal Investigator: Mashima Ryuichi 国立研究開発法人国立成育医療研究センター, 臨床検査部, 専門職 (00401365)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: ムコ多糖症II型 / 酵素活性 / バイオマーカー / LC-MS/MS

Outline of Final Research Achievements

Mucopolysaccharidosis type II (MPS-II, OMIM 309900) is an X-linked disorder characterized by visceral disorder, bone deformation, CNS involvement, as well as an accumulation of glycosaminoglycan in the body. MPS-II is caused by a deficiency of iduronate-2-sulfatase enzyme activity. In this study, thus, we aimed to establish an assay procedure for enzyme activity and biomarkers for MPS-II using LC-MS/MS. First, to quantify the enzyme activity, a 3 mm punch of DBS was incubated with substrate and internal standard. After 20 h of enzyme reaction at 37°C, the enzyme reaction products were extracted and quantified using LC-MS/MS. For the quantification of dermatan sulfate and heparan sulfate, dried urine was reacted in methanolic 3M HCl at 65°C for 75 min. The reaction products were quantified using LC-MS/MS. In both assays, the population of MPS-II-affected individuals was separated from that of controls, demonstrating that diagnosis of MPS-II may be performed with one of these methods.

Free Research Field

臨床検査学

Academic Significance and Societal Importance of the Research Achievements

本研究開始当時において、ムコ多糖症II型患者の酵素活性は少なくとも日本国内においてほとんど蛍光法で測定されていた。従ってLC-MSで測定する有用性を示した本研究の成果は臨床検査学および分析化学的に学術的特色がある。本研究の結果、LC-MS法を採用することで、遺伝的に酵素活性値が低いが罹患しないことが知られている被検者を適切に正常と判定することや、複数疾患を同時に測定可能となった。本研究成果により正確な診断と早期発見が可能になったことから、患者おける治療上の大きなメリットがあり、医療経済的効果がある。また新生児スクリーニングに応用された場合、公衆衛生的意義も高いと考えられる。