scholarly journals Tandem Mass Spectrometry for the Direct Assay of Lysosomal Enzymes in Dried Blood Spots: Application to Screening Newborns for Mucopolysaccharidosis II (Hunter Syndrome)

2011 ◽  
Vol 83 (3) ◽  
pp. 1152-1156 ◽  
Author(s):  
Brian J. Wolfe ◽  
Sophie Blanchard ◽  
Martin Sadilek ◽  
C. Ronald Scott ◽  
Frantisek Turecek ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Lysosomal Enzymes ◽  
Hunter Syndrome ◽  
Dried Blood Spots ◽  
Tandem Mass ◽  
Mucopolysaccharidosis Ii ◽  
Blood Spots ◽  
Direct Assay

scholarly journals Tandem Mass Spectrometry for the Direct Assay of Enzymes in Dried Blood Spots: Application to Newborn Screening for Mucopolysaccharidosis II (Hunter Disease)

2007 ◽  
Vol 53 (1) ◽  
pp. 137-140 ◽  
Author(s):  
Ding Wang ◽  
Tim Wood ◽  
Martin Sadilek ◽  
C Ronald Scott ◽  
Frantisek Turecek ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Internal Standard ◽  
Hunter Syndrome ◽  
Dried Blood Spots ◽  
Assay Method ◽  
Tandem Mass ◽  
Mucopolysaccharidosis Ii ◽  
Blood Spots

Abstract Background: A treatment for mucopolysaccharidosis II (Hunter syndrome) has recently become available. Therefore, we developed a high-throughput assay method appropriate for newborn screening for the relevant enzyme, iduronate 2-sulfatase. Methods: We synthesized a new iduronate 2-sulfatase substrate that can be used to assay the enzyme by use of tandem mass spectrometry together with an internal standard. The assay uses a dried blood spot on a newborn screening card as the enzyme source. Results: When the assay was tested on dried blood spots, the iduronate 2-sulfatase activity measured for 13 patients with Hunter syndrome was well below the interval found for 57 randomly chosen newborns. The assay was more sensitive than previously reported iduronate 2-sulfatase assays. Conclusions: This newly developed tandem mass spectrometry assay has the potential to be adopted for newborn screening of Hunter syndrome. This method also has the potential to be carried out in multiplex fashion to assay several different enzymes relevant to lysosomal storage diseases that are assayed in a single infusion into the mass spectrometer.

scholarly journals A Tandem Mass Spectrometry Triplex Assay for the Detection of Fabry, Pompe, and Mucopolysaccharidosis-I (Hurler)

2010 ◽  
Vol 56 (12) ◽  
pp. 1854-1861 ◽  
Author(s):  
Trisha A Duffey ◽  
Garland Bellamy ◽  
Susan Elliott ◽  
Angela C Fox ◽  
Michael Glass ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Lysosomal Enzymes ◽  
Dried Blood Spots ◽  
Enzymatic Activities ◽  
Simple Liquid ◽  
Tandem Mass ◽  
Internal Standards ◽  
Mucopolysaccharidosis I ◽  
Blood Spots

BACKGROUND We sought to develop a tandem mass spectrometry assay in which the enzymatic activities of 3 lysosomal enzymes (α-glucosidase, α-galactosidase A, and α-l-iduronidase) could be quantified in dried blood spots by using a single assay buffer. METHODS A 3-mm dried blood spot punch was incubated in a single assay buffer with 3 different substrates and internal standards. The sample was processed by a simple liquid-liquid extraction by using ethyl acetate. The extract was dried down and resuspended in solvent for injection into the tandem mass spectrometer. Products and internal standards were monitored by multiple reaction monitoring. RESULTS Assay for the 3 lysosomal enzymes was successfully achieved with acceptable statistics. The assay can be performed by using a minimal quantity of disposable supplies and equipment. The entire procedure fits into a 48-h cycle including data analysis. Data from 5990 anonymous newborn dried blood spots showed an approximate bell-shaped distribution of enzymatic activities (mean values of 19.0, 11.5, and 3.5 μmol · h−1 · (L blood)−1 for α-glucosidase, α-galactosidase A, and α-l-iduronidase, respectively. Blank values obtained in the absence of blood were 0.13, 0.24, and 0.45 μmol · h−1 · (L blood)−1, respectively). By assaying 3 enzymes at once, problematic samples are spotted for reanalysis if enzyme activity values are low for all enzymes (for example, if insufficient blood is present in the assay). CONCLUSIONS This method demonstrates that a triplex assay in a single buffer and with minimal supplies and labor can be adapted to a high-throughput newborn screening laboratory for the analysis of Pompe, Fabry, and mucopolysaccharidosis-I (Hurler) diseases.

scholarly journals Tandem Mass Spectrometry for the Direct Assay of Lysosomal Enzymes in Dried Blood Spots: Application to Screening Newborns for Mucopolysaccharidosis I

2008 ◽  
Vol 54 (12) ◽  
pp. 2067-2070 ◽  
Author(s):  
Sophie Blanchard ◽  
Martin Sadilek ◽  
C Ronald Scott ◽  
Frantisek Turecek ◽  
Michael H Gelb
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Lysosomal Enzymes ◽  
Internal Standard ◽  
Dried Blood Spots ◽  
Simple Liquid ◽  
Tandem Mass ◽  
Mucopolysaccharidosis I ◽  
Blood Spots

Abstract Background: Treatments now available for mucopolysaccharidosis I require early detection for optimum therapy. Therefore, we have developed an assay appropriate for newborn screening of the activity of the relevant enzyme, α-L-iduronidase. Methods: We synthesized a new α-L-iduronidase substrate that can be used to assay the enzyme by use of tandem mass spectrometry together with an internal standard or by fluorometry. The assay uses a dried blood spot on a newborn screening card as the enzyme source. The assay protocol uses a simple liquid-liquid extraction step before mass spectrometry. We optimized enzyme reaction conditions and procedures for the assay, including the concentration of substrate, the reaction pH, the incubation time, and mass spectrometer operation. We also assessed inter- and intraassay imprecision. Results: When the assay was tested on dried blood spots, the α-L-iduronidase activity measured for 5 patients with mucopolysaccharidosis I was well below the interval found for 10 randomly chosen newborns. Inter- and intraassay imprecision were <10%. The synthesis of the α-L-iduronidase substrate is practical for use on a scale needed to support newborn screening demands. Conclusions: This newly developed tandem mass spectrometry assay has the potential to be adopted for newborn screening of mucopolysaccharidosis I. This assay has advantages over a previously reported assay also developed in this laboratory and has the potential to be performed in a multiplex fashion to measure several lysosomal enzymes relevant to treatable lysosomal storage diseases.

scholarly journals Newborn Screening for Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase and Mitochondrial Trifunctional Protein Deficiencies Using Acylcarnitines Measurement in Dried Blood Spots—A Systematic Review of Test Accuracy

2021 ◽  
Vol 9 ◽  
Author(s):  
Chris Stinton ◽  
Hannah Fraser ◽  
Julia Geppert ◽  
Rebecca Johnson ◽  
Martin Connock ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Dried Blood Spots ◽  
Test Accuracy ◽  
Tandem Mass ◽  
Blood Spots ◽  
Hydroxyacyl Coa Dehydrogenase ◽  
Sensitivity Specificity ◽  
Long Chain

Background: Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare autosomal recessive fatty acid β-oxidation disorders. Their clinical presentations are variable, and premature death is common. They are included in newborn blood spot screening programs in many countries around the world. The current process of screening, through the measurement of acylcarnitines (a metabolic by-product) in dried blood spots with tandem mass spectrometry, is subject to uncertainty regarding test accuracy.Methods: We conducted a systematic review of literature published up to 19th June 2018. We included studies that investigated newborn screening for LCHAD or MTP deficiencies by tandem mass spectrometry of acylcarnitines in dried blood spots. The reference standards were urine organic acids, blood acylcarnitine profiles, enzyme analysis in cultured fibroblasts or lymphocytes, mutation analysis, or at least 10-year follow-up. The outcomes of interest were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Assessment of titles, abstracts, and full-text papers and quality appraisal were carried out independently by two reviewers. One reviewer extracted study data. This was checked by a second reviewer.Results: Ten studies provided data on test accuracy. LCHAD or MTP deficiencies were identified in 23 babies. No cases of LCHAD/MTP deficiencies were identified in four studies. PPV ranged from 0% (zero true positives and 28 false positives from 276,565 babies screened) to 100% (13 true positives and zero false positives from 2,037,824 babies screened). Sensitivity, specificity, and NPV could not be calculated as there was no systematic follow-up of babies who screened negative.Conclusions: Test accuracy estimates of screening for LCHAD and MTP deficiencies with tandem mass spectrometry measurement of acylcarnitines in dried blood were variable in terms of PPVs. Screening methods (including markers and thresholds) varied between studies, and sensitivity, specificity, and NPVs are unknown.

Incorporating the measurement of EDTA in dried blood spots (DBS) by tandem mass spectrometry in routine newborn screening

2014 ◽  
Vol 47 (15) ◽  
pp. 144
Author(s):  
Lawrence J. Fisher ◽  
Osama Y. Al-Dirbashi ◽  
Svetlana Ogrel ◽  
Nathan McIntosh ◽  
Michael T. Geraghty ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Dried Blood Spots ◽  
Tandem Mass ◽  
Blood Spots
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