scholarly journals Incorporation of Second-Tier Biomarker Testing Improves the Specificity of Newborn Screening for Mucopolysaccharidosis Type I

2020 ◽  
Vol 6 (1) ◽  
pp. 10 ◽  
Author(s):  
Dawn S. Peck ◽  
Jean M. Lacey ◽  
Amy L. White ◽  
Gisele Pino ◽  
April L. Studinski ◽  
...  
Keyword(s):  
Newborn Screening ◽  
False Positive ◽  
Dermatan Sulfate ◽  
False Positive Rate ◽  
False Negative ◽  
Type I ◽  
Mucopolysaccharidosis Type ◽  
Mucopolysaccharidosis Type I ◽  
Second Tier ◽  
Mps I

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.

scholarly journals The combined use of enzyme activity and metabolite assays as a strategy for newborn screening of mucopolysaccharidosis type I

2020 ◽  
Vol 58 (12) ◽  
pp. 2063-2072 ◽  
Author(s):  
Giulia Polo ◽  
Daniela Gueraldi ◽  
Antonella Giuliani ◽  
Laura Rubert ◽  
Chiara Cazzorla ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Newborn Screening ◽  
False Positives ◽  
Type I ◽  
Mucopolysaccharidosis Type ◽  
Mucopolysaccharidosis Type I ◽  
Hematopoietic Stem ◽  
Enzyme Replacement ◽  
Second Tier ◽  
Mps I

AbstractObjectivesMucopolysaccharidosis type I (MPS I) was added to our expanded screening panel in 2015. Since then, 127,869 newborns were screened by measuring α-L-iduronidase (IDUA) enzyme activity with liquid chromatography tandem mass spectrometry (LC-MS/MS). High false positives due to frequent pseudodeficiency alleles prompted us to develop a second-tier test to quantify glycosaminoglycan (GAG) levels in dried blood spot (DBS).MethodsHeparan-sulfate (HS) and dermatan-sulfate (DS) were measured with LC-MS/MS after methanolysis. DBSs were incubated with methanolic-HCl 3 N at 65 °C for 45 min. Chromatographic separation used an amide column with a gradient of acetonitrile and water with 10 mM ammonium acetate in a 9-min run. The method was validated for specificity, linearity, lower limit of quantification (LOQ), accuracy and precision.ResultsIntra- and inter-day coefficients of variation were <15% for both metabolites. Reference values in 40 healthy newborns were: HS mean 1.0 mg/L, 0–3.2; DS mean 1.5 mg/L, 0.5–2.7). The two confirmed newborn MPS I patients had elevated HS (4.9–10.4 mg/L, n.v. <3.2) and DS (7.4–8.8 mg/L, n.v. <2.7). Since its introduction in February 2019, the second-tier test reduced the recall rate from 0.046% to 0.006%. Among 127,869 specimens screened, the incidence was 1:63,935 live births. Both patients started enzyme replacement therapy (ERT) within 15 days of birth and one of them received allogenic hematopoietic stem cell transplantation (HSCT) at ht age of 6 months.ConclusionsGAGs in DBS increased the specificity of newborn screening for MPS I by reducing false-positives due to heterozygosity or pseudodeficiency. Early diagnosis and therapeutical approach has improved the outcome of our patients with MPS I.

scholarly journals Report of Five Years of Experience in Neonatal Screening for Mucopolysaccharidosis Type I and Review of the Literature

2020 ◽  
Vol 6 (4) ◽  
pp. 85 ◽  
Author(s):  
Vincenza Gragnaniello ◽  
Daniela Gueraldi ◽  
Laura Rubert ◽  
Francesca Manzoni ◽  
Chiara Cazzorla ◽  
...  
Keyword(s):  
Early Diagnosis ◽  
Early Treatment ◽  
Molecular Testing ◽  
Type I ◽  
Mucopolysaccharidosis Type ◽  
Mucopolysaccharidosis Type I ◽  
Years Of Experience ◽  
Enzyme Replacement ◽  
Second Tier ◽  
Mps I

Mucopolysaccharidosis type I (MPS I) is a progressive lysosomal storage disease, with neurological and visceral involvement, in which early diagnosis through newborn screening (NBS) and early treatment can improve outcomes. We present our first 5 years of experience with laboratory and clinical management of NBS for MPS I. Since 2015, we have screened 160,011 newborns by measuring α-L-iduronidase (IDUA) activity and, since 2019, glycosaminoglycans (GAGs) in dried blood spot (DBS) as a second-tier test. Positive screening patients were referred to our clinic for confirmatory clinical and molecular testing. We found two patients affected by MPS I (incidence of 1:80,005). Before the introduction of second-tier testing, we found a high rate of false-positives due to pseudodeficiency. With GAG analysis in DBS as a second-tier test, no false-positive newborns were referred to our clinic. The confirmed patients were early treated with enzyme replacement therapy and bone-marrow transplantation. For both, the clinical outcome of the disease is in the normal range. Our experience confirms that NBS for MPS I is feasible and effective, along with the need to include GAG assay as a second-tier test. Follow-up of the two positive cases identified confirms the importance of early diagnosis through NBS and early treatment to improve the outcome of these patients.

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

2020 ◽  
Vol 6 (1) ◽  
pp. 2 ◽  
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.

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

2019 ◽  
Vol 5 (2) ◽  
pp. 24 ◽  
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.

Mucopolysaccharidosis type I newborn screening: Importance of second tier testing for ethnically diverse populations

2020 ◽  
Vol 185 (1) ◽  
pp. 134-140
Author(s):  
Kerri Bosfield ◽  
Debra S. Regier ◽  
Sarah Viall ◽  
Rebecca Hicks ◽  
Natasha Shur ◽  
...  
Keyword(s):  
Newborn Screening ◽  
Ethnically Diverse ◽  
Type I ◽  
Mucopolysaccharidosis Type ◽  
Mucopolysaccharidosis Type I ◽  
Diverse Populations ◽  
Second Tier

scholarly journals Cathepsin B-associated Activation of Amyloidogenic Pathway in Murine Mucopolysaccharidosis Type I Brain Cortex

2020 ◽  
Vol 21 (4) ◽  
pp. 1459 ◽  
Author(s):  
Gustavo Monteiro Viana ◽  
Esteban Alberto Gonzalez ◽  
Marcela Maciel Palacio Alvarez ◽  
Renan Pelluzzi Cavalheiro ◽  
Cinthia Castro do Nascimento ◽  
...  
Keyword(s):  
Cathepsin B ◽  
Dermatan Sulfate ◽  
Fluorescent Microscopy ◽  
Type I ◽  
Mucopolysaccharidosis Type ◽  
Mucopolysaccharidosis Type I ◽  
Lysosomal Storage ◽  
App Processing ◽  
Mps I

Mucopolysaccharidosis type I (MPS I) is caused by genetic deficiency of α-l-iduronidase and impairment of lysosomal catabolism of heparan sulfate and dermatan sulfate. In the brain, these substrates accumulate in the lysosomes of neurons and glial cells, leading to neuroinflammation and neurodegeneration. Their storage also affects lysosomal homeostasis-inducing activity of several lysosomal proteases including cathepsin B (CATB). In the central nervous system, increased CATB activity has been associated with the deposition of amyloid plaques due to an alternative pro-amyloidogenic processing of the amyloid precursor protein (APP), suggesting a potential role of this enzyme in the neuropathology of MPS I. In this study, we report elevated levels of protein expression and activity of CATB in cortex tissues of 6-month-old MPS I (Idua -/- mice. Besides, increased CATB leakage from lysosomes to the cytoplasm of Idua -/- cortical pyramidal neurons was indicative of damaged lysosomal membranes. The increased CATB activity coincided with an elevated level of the 16-kDa C-terminal APP fragment, which together with unchanged levels of β-secretase 1 was suggestive for the role of this enzyme in the amyloidogenic APP processing. Neuronal accumulation of Thioflavin-S-positive misfolded protein aggregates and drastically increased levels of neuroinflammatory glial fibrillary acidic protein (GFAP)-positive astrocytes and CD11b-positive activated microglia were observed in Idua -/- cortex by confocal fluorescent microscopy. Together, our results point to the existence of a novel CATB-associated alternative amyloidogenic pathway in MPS I brain induced by lysosomal storage and potentially leading to neurodegeneration.

scholarly journals Sexual behaviour in a murine model of mucopolysaccharidosis type I (MPS I)

PLoS ONE ◽  
2019 ◽  
Vol 14 (12) ◽  
pp. e0220429 ◽  
Author(s):  
Ana Barbosa Mendes ◽  
Cinthia Castro do Nascimento ◽  
Vânia D’Almeida
Keyword(s):  
Sexual Behaviour ◽  
Murine Model ◽  
Type I ◽  
Mucopolysaccharidosis Type ◽  
Mucopolysaccharidosis Type I ◽  
Mps I

scholarly journals Mucopolysaccharidosis type I - Clinical and genetic characteristics of Romanian patients

2020 ◽  
Vol 28 (3) ◽  
pp. 279-286
Author(s):  
Camelia Alkhzouz ◽  
Cecilia Lazea ◽  
Diana Miclea ◽  
Carmen Asavoaie ◽  
Ioana Nascu ◽  
...  
Keyword(s):  
Severe Form ◽  
The Other ◽  
Compound Heterozygous ◽  
Type I ◽  
Ophthalmological Examination ◽  
Mucopolysaccharidosis Type ◽  
Hurler Syndrome ◽  
Mucopolysaccharidosis Type I ◽  
Genetic Characteristics ◽  
Mps I

AbstractBackground: Mucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder caused by a deficiency of α-L-iduronidase (IDUA), which leads to the accumulation of partially digested glycosaminoglycans (dermatan sulfate and heparan sulfate) in the lysosomes and induces multisystemic alteration. Hurler (severe), Scheie (mild), and Hurler/Scheie (intermediate) syndromes are clinical subtypes of MPS-I. To date, more than 290 IDUA mutations have been reported. The purpose of this study was to present the clinical and genetic characteristics of Romanian MPS I syndrome patients and their genotype-phenotype correlation.Patients and methods: Seven patients (5 girls and 2 boys) with MPS type I, belonging to 4 unrelated families, aged 0,75-17.9 years, were enrolled. The study methods consisted in: clinical and standard auxological assessment, bone radiographs, joint ultrasonography, goniometry, neurological and psychological evaluation, hepatic and splenic ultrasonography, cardiological evaluation, otorhinolaryngology examination, ophthalmological examination, spirometry, α-L-iduronidase enzyme activity assay and molecular analysis.Results: The seven patients originated from 4 unrelated families, three patients with severe, two patients with intermediate and two with attenuated clinical phenotype. Each patient presented the classical picture of MPS type I picture, represented by: variable coarse facial features, arthropathy, hepatosplenomegaly, cardiac involvement, respiratory dysfunction and neurological impairment. Five patological variants, three point mutations (p.Q70 *, p.I238Q and p.K324R), two deletion c.1045_1047delGAC, c.46_57delTCGCTCCTG) and an insertion (c.1389 insC) were identified in both alleles of the ADUA gene in homozygous or heterozygous form. Two novel mutations (p.K324R and c.1389 insC) were reported. The p.Q70*(c.208C>T) variant was identified in 2 families with severe form of disease (Hurler syndrome) in homozygous status in one family and in compound heterozygous status in the other family.Conclusion: The p.Q70* missense variant was the most frequent, correlated in all the cases who presented it with severe form, Hurler syndrome, the other mutations being usually isolated and particular for each patient, associated in our patients with less severe MPS I phenotype, as Hurler-Scheie or Scheie syndrome. The results of this study indicated the mutational heterogeneity of the IDUA gene and the difficulty to indicate some correlation between the genotype and phenotype in MPS I patients.

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