Tandem Mass Spectrometry for the Direct Assay of Lysosomal Enzymes in Dried Blood Spots:Application to Screening Newborns for Mucopolysaccharidosis IVA
| Autor: | Tanvir Khaliq, František Tureček, Michael H. Gelb, Martin Sadilek, C. Ronald Scott |
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| Rok vydání: | 2011 |
| Předmět: |
Spectrometry
Mass Electrospray Ionization Mucopolysaccharidosis Clinical Biochemistry Tandem mass spectrometry Mass spectrometry Article Substrate Specificity Neonatal Screening Tandem Mass Spectrometry Mucopolysaccharidosis I medicine Humans Multiplex Umbelliferones Blood Specimen Collection biology Chemistry Sulfatase Biochemistry (medical) Infant Newborn Mucopolysaccharidosis IV medicine.disease Chondroitinsulfatases Enzyme assay Biochemistry biology.protein Lysosomes |
| Zdroj: | Clinical Chemistry. 57:128-131 |
| ISSN: | 1530-8561 0009-9147 |
| DOI: | 10.1373/clinchem.2010.149880 |
| Popis: | BACKGROUND Treatments are being developed for an increasing number of mucopolysaccharidoses, and early diagnosis is expected to be necessary to maximize the benefits of therapy. Therefore, we developed an assay for N-acetylgalactosamine-6-sulfate sulfatase (GALNS), the enzyme deficient in mucopolysaccharidosis IVA (Morquio A syndrome), that is applicable for clinical diagnosis. METHODS A novel substrate for GALNS was synthesized for a new enzyme activity assay that is based on tandem mass spectrometry and uses dried blood spots (DBSs) as the enzyme source. We optimized the assay conditions, including the substrate concentration, reaction pH, lead formate concentration, incubation time, punch size of the DBS, and mass spectrometer conditions. We also assessed inter- and intraassay variation. RESULTS The assay uses either solid-phase or liquid-phase extraction before analysis by mass spectrometry. An evaluation of blood spots from 90 randomly chosen healthy newborns and 9 patients with Morquio A syndrome showed a well-defined interval between their respective enzyme activities. Inter- and intraassay imprecision was CONCLUSIONS This tandem mass spectrometry assay requires a minimal number of sample-preparation steps, thus making it easy to implement. The assay has the potential to be adopted for early diagnosis of Morquio A syndrome. We believe this assay could be performed in a multiplex fashion with assays for other lysosomal enzymes. |
| Databáze: | OpenAIRE |
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