Development of a newborn screening tool for mucopolysaccharidosis type I based on bivariate normal limits: Using glycosaminoglycan and alpha‐L‐iduronidase determinations on dried blood spots to predict symptoms

Enzyme-based newborn screening for Mucopolysaccharidosis type I (MPS I) has a high false-positive rate due to the prevalence of pseudodeficiency alleles, often resulting in unnecessary and costly follow up. The glycosaminoglycans (GAGs), dermatan sulfate (DS) and heparan sulfate (HS) are both substrates for α-l-iduronidase (IDUA). These GAGs are elevated in patients with MPS I and have been shown to be promising biomarkers for both primary and second-tier testing. Since February 2016, we have measured DS and HS in 1213 specimens submitted on infants at risk for MPS I based on newborn screening. Molecular correlation was available for 157 of the tested cases. Samples from infants with MPS I confirmed by IDUA molecular analysis all had significantly elevated levels of DS and HS compared to those with confirmed pseudodeficiency and/or heterozygosity. Analysis of our testing population and correlation with molecular results identified few discrepant outcomes and uncovered no evidence of false-negative cases. We have demonstrated that blood spot GAGs analysis accurately discriminates between patients with confirmed MPS I and false-positive cases due to pseudodeficiency or heterozygosity and increases the specificity of newborn screening for MPS I.

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Combined Newborn Screening for Succinylacetone, Amino Acids, and Acylcarnitines in Dried Blood Spots

Clinical Chemistry ◽

10.1373/clinchem.2007.101949 ◽

2008 ◽

Vol 54 (4) ◽

pp. 657-664 ◽

Cited By ~ 102

Author(s):

Coleman Turgeon ◽

Mark J Magera ◽

Pierre Allard ◽

Silvia Tortorelli ◽

Dimitar Gavrilov ◽

...

Keyword(s):

Amino Acids ◽

Newborn Screening ◽

False Negative ◽

Internal Standard ◽

Early Death ◽

Cost Effective ◽

Dried Blood Spots ◽

Type I ◽

Blood Spots ◽

Negative Results

Abstract Background: Tyrosinemia type I (TYR 1) is a disorder causing early death if left untreated. Newborn screening (NBS) for this condition is problematic because determination of the diagnostic marker, succinylacetone (SUAC), requires a separate first-tier or only partially effective second-tier analysis based on tyrosine concentration. To overcome these problems, we developed a new assay that simultaneously determines acylcarnitines (AC), amino acids (AA), and SUAC in dried blood spots (DBS) by flow injection tandem mass spectrometry (MS/MS). Methods: We extracted 3/16-inch DBS punches with 300 μL methanol containing AA and AC stable isotope-labeled internal standards. This extract was derivatized with butanol-HCl. In parallel, we extracted SUAC from the residual filter paper with 100 μL of a 15 mmol/L hydrazine solution containing the internal standard 13C5-SUAC. We combined the derivatized aliquots in acetonitrile for MS/MS analysis of AC and AA with additional SRM experiments for SUAC (m/z 155–137) and 13C5-SUAC (m/z 160–142). Analysis time was 1.2 min. Results: SUAC was increased in retrospectively analyzed NBS samples of 11 TYR 1 patients (length of storage, 52 months to 1 week; SUAC range, 13–81 μmol/L), with Tyr concentrations ranging from 65 to 293 μmol/L in the original NBS analysis. The mean concentration of SUAC in 13 521 control DBS was 1.25 μmol/L. Conclusion: The inclusion of SUAC analysis into routine analysis of AC and AA allows for rapid and cost-effective screening for TYR 1 with no tangible risk of false-negative results.

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Two-Tiered Newborn Screening with Post-Analytical Tools for Pompe Disease and Mucopolysaccharidosis Type I Results in Performance Improvement and Future Direction

International Journal of Neonatal Screening ◽

10.3390/ijns6010002 ◽

2020 ◽

Vol 6 (1) ◽

pp. 2 ◽

Cited By ~ 5

Author(s):

Patricia L. Hall ◽

Rossana Sanchez ◽

Arthur F. Hagar ◽

S. Caleb Jerris ◽

Angela Wittenauer ◽

...

Keyword(s):

Newborn Screening ◽

Pompe Disease ◽

Late Onset ◽

Screening Program ◽

Molecular Testing ◽

Type I ◽

Mucopolysaccharidosis Type ◽

Mucopolysaccharidosis Type I ◽

Analytical Tools ◽

Mps I

We conducted a pilot newborn screening (NBS) study for Pompe disease (PD) and mucopolysaccharidosis type I (MPS I) in the multiethnic population of Georgia. We screened 59,332 infants using a two-tier strategy of flow injection tandem mass spectrometry (FIA-MSMS) enzyme assays. The first tier of testing was a 2-plex assay measuring PD and MPS I enzyme activity, followed by a second-tier test with additional enzymes to improve specificity. Interpretation of results was performed using post-analytical tools created using Collaborative Laboratory Integrated Reports (CLIR). We identified a single case of infantile onset PD, two cases of late onset PD, and one pseudodeficiency. The positive predictive value (PPV) for PD screening during the study was 66.7%. No cases of MPS I were identified during the study period, but there were 2 confirmed cases of pseudodeficiency and 6 cases lost to follow up. The two-tier screening strategy was successful in reducing false positive results and allowed for the identification and early treatment of a case of infantile PD but the frequency of pseudodeficiency in MPS I is problematic. Molecular testing is required and should be covered by the screening program to avoid delays in case resolution.

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A column-switching HPLC-MS/MS method for mucopolysaccharidosis type I analysis in a multiplex assay for the simultaneous newborn screening of six lysosomal storage disorders

Biomedical Chromatography ◽

10.1002/bmc.3133 ◽

2014 ◽

Vol 28 (8) ◽

pp. 1131-1139 ◽

Cited By ~ 11

Author(s):

Antonina Gucciardi ◽

Elisa Legnini ◽

Iole Maria Di Gangi ◽

Carlo Corbetta ◽

Rosella Tomanin ◽

...

Keyword(s):

Newborn Screening ◽

Column Switching ◽

Multiplex Assay ◽

Lysosomal Storage Disorders ◽

Type I ◽

Mucopolysaccharidosis Type ◽

Mucopolysaccharidosis Type I ◽

Lysosomal Storage ◽

Storage Disorders

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Implementation of Second-Tier Tests in Newborn Screening for Lysosomal Disorders in North Eastern Italy

International Journal of Neonatal Screening ◽

10.3390/ijns5020024 ◽

2019 ◽

Vol 5 (2) ◽

pp. 24 ◽

Cited By ~ 15

Author(s):

Alberto B. Burlina ◽

Giulia Polo ◽

Laura Rubert ◽

Daniela Gueraldi ◽

Chiara Cazzorla ◽

...

Keyword(s):

Newborn Screening ◽

Lysosomal Storage Diseases ◽

Type I ◽

Mucopolysaccharidosis Type ◽

Mucopolysaccharidosis Type I ◽

Lysosomal Storage ◽

Storage Diseases ◽

Lysosomal Disorders ◽

North Eastern ◽

Second Tier

The increasing availability of treatments and the importance of early intervention have stimulated interest in newborn screening for lysosomal storage diseases. Since 2015, 112,446 newborns in North Eastern Italy have been screened for four lysosomal disorders—mucopolysaccharidosis type I and Pompe, Fabry and Gaucher diseases—using a multiplexed tandem mass spectrometry (MS/MS) assay system. We recalled 138 neonates (0.12%) for collection of a second dried blood spot. Low activity was confirmed in 62 (0.06%), who underwent confirmatory testing. Twenty-five neonates (0.02%) were true positive: eight with Pompe disease; seven with Gaucher disease; eight with Fabry disease; and two with Mucopolysaccharidosis type I. The combined incidence of the four disorders was 1 in 4497 births. Except for Pompe disease, a second-tier test was implemented. We conclude that newborn screening for multiple lysosomal storage diseases combined with a second-tier test can largely eliminate false-positives and achieve rapid diagnosis.

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