Elevated methylmalonic acidemia (MMA) screening markers in Hispanic and preterm newborns

Mol Genet Metab. 2019 Jan;126(1):39-42. doi: 10.1016/j.ymgme.2018.11.006. Epub 2018 Nov 10.


Analysis of California newborn screening (NBS) data revealed a high prevalence of Hispanic infants testing positive for methylmalonic acidemia (MMA), a trend seen for both true- and false-positive cases. Here we show that Hispanic infants have significantly higher levels of MMA screening markers than non-Hispanics. Preterm birth and increased birth weight were found to be associated with elevated MMA marker levels but could not entirely explain these differences. While the preterm birth rate was higher in Blacks than Hispanics, Black infants had on average the lowest MMA marker levels. Preterm birth was associated with lower birth weight and increased MMA marker levels suggesting that gestational age is the stronger predictive covariate compared to birth weight. These findings could help explain why MMA false-positive results are more likely in Hispanic than in Black infants, which could inform screening and diagnostic procedures for MMA and potentially other disorders in newborns.

Keywords: Genetics; Inborn metabolic disorders; Metabolism; Newborn screening; Public Health.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • African Americans / statistics & numerical data
  • Amino Acid Metabolism, Inborn Errors / diagnosis*
  • Amino Acid Metabolism, Inborn Errors / ethnology*
  • Biomarkers / blood
  • Birth Weight
  • California / epidemiology
  • False Positive Reactions
  • Female
  • Gestational Age
  • Hispanic Americans* / statistics & numerical data
  • Humans
  • Infant, Newborn
  • Male
  • Methylmalonic Acid / blood
  • Neonatal Screening
  • Premature Birth / ethnology*
  • Public Health


  • Biomarkers
  • Methylmalonic Acid

Supplementary concepts

  • Methylmalonic acidemia