A False-Positive Case of Methylmalonic Aciduria by Tandem Mass Spectrometry Newborn Screening Dependent on Maternal Malnutrition in Pregnancy.

ABSTRACT: Methylmalonic Acidurias (MMAs) are a group of inborn errors of metabolism (IEMs), specifically of propionate catabolism characterized by gastrointestinal and neurometabolic manifestations resulting from a deficiency in the function of methylmalonyl-CoA mutase, methylmalonyl-CoA epimerase, and cobalamin metabolism. In Expanded Newborn Screening (NBS), increased levels of propionylcarnitine (C3) and/or of its ratios by MS/MS analysis of dried blood spots (DBS) samples are suggestive for either Propionic Acidemia or MMAs. C3 elevation is not considered a specific marker for these disorders, resulting in high false-positive rates. The use of analyte ratios improves specificity, but it still cannot resolve the diagnostic issue. Second-tier testing are strongly recommended as confirmation of pri

SUBMITTER: Rossi C 

PROVIDER: S-EPMC7277087 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature