Maternal isovaleric acidemia: Observation of distinctive changes in plasma amino acids and carnitine profiles during pregnancy

Abstract

Background Tandem mass spectrometry based newborn screening programs (NBS) allow early diagnosis and treatment for a number of inborn metabolic disorders. Despite the improved prognosis of affected individuals, the knowledge regarding the potential risks of childbearing in many of these conditions remains limited. Newborns with isovaleric acidemia (IVA) have been diagnosed by NBS and most of them can thrive and develop normally. Many affected individuals will therefore reach childbearing age in the near future. The information about maternal IVA, however, is quite limited. Case report Close observation of plasma amino acid, carnitine, and acylcarnitine profiles was performed in a patient with IVA that completed uneventful pregnancy. Plasma isovalerylcarnitine level was drastically decreased from the second trimester and free carnitine was inversely increased, suggesting reduced production of isovaleryl-CoA. This decrease of isovaleryl-CoA production was likely due to reduced leucine metabolism, secondary to the enhanced fetal anabolism associated with the rapid fetal growth of the second and the third trimesters. A decrease in maternal essential amino acids, including leucine was observed during the second and the third trimesters. Conclusion This observation revealed distinctive metabolic profiles during pregnancy in a patient with IVA and supports close laboratory monitoring and diet management for successful pregnancy.