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Citrullinaemia type I: a common mutation in the Pacific Island population

Emma Glamuzina1, Renate Marquis-Nicholson, Detlef Knoll

  • 1Paediatric Metabolic Service, Starship Children's Hospital, Auckland, New Zealand.

Journal of Paediatrics and Child Health
|January 20, 2011
PubMed

Insights

A new ASS1 gene mutation screening protocol helps diagnose citrullinaemia type I in neonates. This method confirms diagnosis and predicts disease severity, identifying a common mutation in Pacific Island populations.

Area of Science:

  • Biochemistry
  • Genetics
  • Newborn Screening

Background:

  • Expanded newborn screening (E-NBS) identifies neonates with elevated citrulline.
  • Citrullinaemia type I diagnosis requires confirmation, often through genetic analysis.
  • The ASS1 gene is crucial for urea cycle function and citrulline metabolism.

Purpose of the Study:

  • To develop and implement a mutation screening protocol for the ASS1 gene.
  • To confirm diagnoses of citrullinaemia type I in neonates identified by E-NBS.
  • To correlate ASS1 gene mutations with clinical presentation and disease severity.

Main Methods:

  • Identified three neonates with elevated citrulline via E-NBS.
  • Applied polymerase chain reaction (PCR) and sequencing to analyze the ASS1 gene.
  • Utilized a rapid mutation-specific detection method and followed clinical progress.

Main Results:

  • All three patients were homozygous for the missense mutation c.787G>A (p.Val263Met) in the ASS1 gene.
  • This mutation is associated with a mild or asymptomatic clinical course.
  • The same mutation was found in all patients, irrespective of non-consanguinity or Pacific Island origin.

Conclusions:

  • Rapid ASS1 gene sequencing confirms citrullinaemia type I and helps infer phenotypic severity in screened neonates.
  • The identified mutation (c.787G>A) may be prevalent in specific ethnic groups, suggesting a possible founder effect.
  • This protocol aids in managing neonates with elevated citrulline detected through E-NBS.
Abstract

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