title: Newborn screening and diagnosis of mucopolysaccharidoses: application of tandem mass spectrometry.
abstract: Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by the deficiency of lysosomal enzymes. The enzymes are required to break down glycosaminoglycans (GAGs) that help build bone, cartilage, tendons, corneas, skin and connective tissue. In patients with MPS, a missing enzyme leads to the accumulation of GAGs in the cells, blood, connective tissues, and multiple organs. The consequence is permanent, with progressive cellular damage affecting patients' appearance, physical abilities, organ and system function, and skeletal and mental development. The measurement of each specific GAG in a variety of specimens is required to establish the correlation between GAGs and physiological status of patients and/or prognosis and pathogenesis of the disease and to separate the patients with MPS from the healthy controls. We have developed a highly accurate, sensitive, and cost-effective liquid chromatography tandem mass spectrometry (LC-MS/MS) method for measurements of disaccharides derived from four specific GAGs [chondroitin sulfate (CS), dermatan sulfate (DS), heparan sulfate (HS), and keratan sulfate (KS)]. Disaccharides were produced by specific enzyme digestion of each GAG, and subsequently, quantified by negative ion mode of multiple reaction monitoring. Subclasses of GAGs with the same molecular weights can be separated by liquid chromatography. We have also developed another GAG assay by high-throughput mass spectrometry (HT-MS/MS). The HT-MS/MS consists of an integrated solid phase extraction robot that binds and de-salts samples from assay plates and directly injects them into a MS/MS detector, reducing sample processing time to within ten seconds. HT-MS/MS consequently yields much faster throughput than conventional LC-MS/MS-based methods; however, the HT-MS/MS system does not use a chromatographic step, and therefore, cannot separate GAGs that have the same molecular weights. Both techniques can be applied to the analysis of dried blood spots, blood, and urine specimens. In this review, we describe the assay methods for GAGs and the application to newborn screening and diagnosis of MPS.
authors.affiliation: Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE ; Department of Pediatrics, Gifu University, Gifu, Japan.
authors.forename: Shunji
authors.initials: S
authors.lastname: Tomatsu
authors.affiliation: Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE ; Department of Biological Sciences, University of Delaware, Newark, DE.
authors.forename: Francyne
authors.initials: F
authors.lastname: Kubaski
authors.affiliation: Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sawamoto
authors.affiliation: Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Mason
authors.affiliation: Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE.
authors.forename: Eriko
authors.initials: E
authors.lastname: Yasuda
authors.affiliation: Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Shimada
authors.affiliation: Department of Pediatrics, Saint Louis University, St. Louis, Missouri, USA.
authors.forename: Adriana M
authors.initials: AM
authors.lastname: Montaño
authors.affiliation: Department of Pediatrics, Shimane University, Izumo, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Medical Education Development Center, Gifu University.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Pediatrics, Gifu University, Gifu, Japan.
authors.forename: Tadao
authors.initials: T
authors.lastname: Orii
keywords: diagnosis; glycosaminoglycans; mucopolysaccharidoses; newborn screening; tandem mass spectrometry