Elevated neonatal 3-OH isovalerylcarnitine due to breast milk sources in maternal 3-MCC deficiency

Abstract

We report a positive newborn screen for 3-hydroxyisovalerylcarnitine (C 5OH) with an absence of 3-methylcrotonyl-coenzyme A carboxylase deficiency in the neonate. Subsequent blood tests demonstrated persistently elevated C 5OH. Serial testing of the mother identified markedly elevated C 5OH in both maternal blood and breast milk. High C 5OH milk concentrations provide a significant source of C 5OH to the nursing neonate and possibly explains its persistent elevation in the neonate, a commonly observed finding in maternal 3-MCC deficiency.