Maple syrup urine disease: Further evidence that newborn screening may fail to identify variant forms

R. L. Puckett, F. Lorey, P. Rinaldo, M. H. Lipson, D. Matern, M. E. Sowa, S. Levine, R. Chang, R. Y. Wang, J. E. Abdenur

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Newborn screening (NBS) by tandem mass spectrometry (MS/MS) has allowed for early detection and initiation of treatment in many patients with maple syrup urine disease (MSUD) (OMIM 248600), however, a recent report suggests that variants forms may be missed. Information on these patients is limited. We present clinical, biochemical and molecular information on patients with variant forms of MSUD not detected by the California Newborn Screening Program. Between July 2005 and July 2009, 2200,000 newborns were screened in California by MS/MS. Seventeen cases of MSUD were detected and three (two siblings) were missed. Additionally, the NBS cards of two siblings with late onset MSUD, who were born pre-expanded NBS, were retrospectively analyzed. None of the five patients met criteria to be considered presumptive positive for MSUD (leucine > 200 μmol/L and a ratio of leucine/alanine ≥ 1.5). Alloisoleucine (allo-ile) was subsequently analyzed in the NBS cards of all five patients, two of whom were found to have elevated levels. The proband in each family was diagnosed following symptoms triggered by an intercurrent illness or increased protein intake. At diagnosis, leucine levels ranged between 561 and >4528 μmol/L, and allo-ile ranged from 137 to 239 μmol/L. Two affected siblings had normal plasma amino acids when asymptomatic; however, their biochemical profiles were diagnostic of MSUD during intercurrent illnesses. The median age at diagnosis of all patients was one year (range 0.8-6.7). Heterozygous BCKDHB (E1β) mutations (c.832G > A/c.970C > T) were identified in one family and a homozygous DBT (E2) sequence variant (c.1430 T > G) in another. The third family had one identifiable DBT mutation (c.827T > G), however, a second mutation was not detected. This report provides further evidence that NBS by MS/MS is unable to detect all cases of MSUD. Second-tier testing with allo-ile may improve sensitivity; however, some children with variant forms will invariably be missed.

Original languageEnglish (US)
Pages (from-to)136-142
Number of pages7
JournalMolecular Genetics and Metabolism
Volume100
Issue number2
DOIs
StatePublished - Jun 2010

Fingerprint

Maple Syrup Urine Disease
Screening
Newborn Infant
Leucine
Siblings
Mutation
Genetic Databases
Isoleucine
Tandem Mass Spectrometry
Alanine
Mass spectrometry
Plasmas
Amino Acids
Testing

Keywords

  • Alloisoleucine
  • Branched-chain α-keto acid dehydrogenase
  • Branched-chain amino acids
  • Maple syrup urine disease
  • Newborn screening

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Genetics
  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Puckett, R. L., Lorey, F., Rinaldo, P., Lipson, M. H., Matern, D., Sowa, M. E., ... Abdenur, J. E. (2010). Maple syrup urine disease: Further evidence that newborn screening may fail to identify variant forms. Molecular Genetics and Metabolism, 100(2), 136-142. https://doi.org/10.1016/j.ymgme.2009.11.010

Maple syrup urine disease : Further evidence that newborn screening may fail to identify variant forms. / Puckett, R. L.; Lorey, F.; Rinaldo, P.; Lipson, M. H.; Matern, D.; Sowa, M. E.; Levine, S.; Chang, R.; Wang, R. Y.; Abdenur, J. E.

In: Molecular Genetics and Metabolism, Vol. 100, No. 2, 06.2010, p. 136-142.

Research output: Contribution to journalArticle

Puckett, RL, Lorey, F, Rinaldo, P, Lipson, MH, Matern, D, Sowa, ME, Levine, S, Chang, R, Wang, RY & Abdenur, JE 2010, 'Maple syrup urine disease: Further evidence that newborn screening may fail to identify variant forms', Molecular Genetics and Metabolism, vol. 100, no. 2, pp. 136-142. https://doi.org/10.1016/j.ymgme.2009.11.010
Puckett, R. L. ; Lorey, F. ; Rinaldo, P. ; Lipson, M. H. ; Matern, D. ; Sowa, M. E. ; Levine, S. ; Chang, R. ; Wang, R. Y. ; Abdenur, J. E. / Maple syrup urine disease : Further evidence that newborn screening may fail to identify variant forms. In: Molecular Genetics and Metabolism. 2010 ; Vol. 100, No. 2. pp. 136-142.
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