title: Maternal 3-methylcrotonyl-coenzyme A carboxylase deficiency with elevated 3-hydroxyisovalerylcarnitine in breast milk.
abstract: We report here a case of maternal 3-methylcrotonyl-coenzyme A carboxylase (3-MCC) deficiency in a Korean woman. Her 2 infants had elevated 3-hydroxyisovalerylcarnitine (C5-OH) on a neonatal screening test by liquid chromatography-tandem mass spectrometry (LC-MS/MS), but normal results were found on urine organic acid analysis. The patient was subjected to serial testing and we confirmed a maternal 3-MCC deficiency by blood spot and breast milk spot test by LC-MS/MS, serum amino acid analysis, urine organic acid and molecular genetic analysis that found c.838G>T (p.Asp280Tyr) homozygous mutation within exon 9 of the MCCB gene. Especially, we confirmed marked higher levels of C5-OH on breast milk spot by LC-MS/MS, in the case of maternal 3-MCC deficiency vs.
  
  
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authors.affiliation: Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
authors.forename: Kyung Lae
authors.initials: KL
authors.lastname: Cho
authors.affiliation: Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
authors.forename: Yeo Jin
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Green Cross Reference Laboratory, Seoul, Korea.
authors.forename: Song Hyun
authors.initials: SH
authors.lastname: Yang
authors.affiliation: Medical Genetics Center, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Gu-Hwan
authors.initials: GH
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
authors.forename: Jun Hwa
authors.initials: JH
authors.lastname: Lee
keywords: 3-Hydroxyisovalerylcarnitine; 3-MCC deficiency; Breast milk; Korean