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Newborn Screening for Vitamin B6 Non-responsive Classical Homocystinuria: Systematical Evaluation of a Two-Tier

Jürgen G Okun1, Hongying Gan-Schreier2, Tawfeq Ben-Omran3

  • 1Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital, Heidelberg, Germany. juergen.okun@med.uni-heidelberg.de.

JIMD Reports
|June 22, 2016
PubMed

Insights

Early detection of classical homocystinuria (HCU) is crucial. A new two-tier newborn screening strategy using methionine to phenylalanine ratio and homocysteine levels demonstrates 100% accuracy in identifying HCU cases.

Area of Science:

  • Biochemistry
  • Genetics
  • Public Health

Background:

  • Classical homocystinuria (HCU) is a genetic disorder treatable with early intervention.
  • Existing newborn screening methods require optimization for HCU detection.

Purpose of the Study:

  • To develop and validate a cost-effective two-tier strategy for newborn screening of HCU.
  • To improve the efficiency and accuracy of HCU detection in neonates.

Main Methods:

  • Reevaluation of a large newborn screening dataset (125,047 neonates) from Qatar.
  • Analysis included homocysteine (Hcy), methionine (Met), and Met to phenylalanine (Phe) ratio.
  • Cross-validation with international newborn screening programs.

Main Results:

  • The Met to Phe ratio effectively screened out approximately 90% of normal samples in the first tier.
  • Only 10% of samples required a second-tier Hcy measurement.
  • The strategy achieved 100% sensitivity and specificity in HCU screening.

Conclusions:

  • A two-tier algorithm utilizing Met to Phe ratio followed by Hcy measurement is highly effective for HCU newborn screening.
  • This optimized strategy enhances diagnostic accuracy while reducing laboratory workload.
  • The findings support the implementation of this improved screening protocol globally.
Abstract

Keywords:
Classical homocystinuriaCystathionine β-synthaseDried blood spotsHomocysteineNewborn screeningTwo-tier strategy

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