Pregnancy in an adolescent with maple syrup urine disease: Case report

Abstract

Maple syrup urine disease (MSUD, MIM #248600) is an autosomal recessive metabolic disorder that results in elevation of the branched-chain amino acids (BCAA) leucine, isoleucine, and valine. Elevation of BCAA and certain alpha keto-acids is associated with a catabolic state and may result in neurological and developmental delays, feeding problems, and a urine and cerumen odor of maple syrup. Pregnancy is a period of multiple adaptations necessary to support fetal growth and development. Both the third trimester of pregnancy and the postpartum period present the possibility for catabolic states. We describe our treatment of an adolescent patient with intermittent MSUD and her resulting positive pregnancy outcome.

Keywords: Catabolic state; MSUD; Pregnancy.

Fig. 1

Overview of the BCAA catabolic pathway. BCAA leucine, isoleucine, and valine undergo transamination that is catalyzed by branched-chain aminotransferase (BCAT). This reaction requires α-Ketoglutarate, leading to the production of α-ketoacids α-ketoisocaproic acid (KIC), α-keto-β-methylvaleric acid (KMV), and α-ketoisovaleric acid (KIV). These intermediates undergo oxidative decarboxylation, catalyzed by the branched-chain α-ketoacid dehydrogenase (BCKAD) complex. Figure reprinted from Blackburn PR, Gass JM, Pinto e Vairo F, Farnham KM, Atwal HK, Macklin S et al. Maple syrup urine disease: mechanisms and management. Appl Clin Genet. 2017; 10: 57–66. This figure has been reproduced with permission from Dove Medical Press.