Intermittent Maple Syrup Urine Disease: Two Case Reports

The presenting symptoms and clinical course of 2 cases of intermittent maple syrup urine disease (MSUD) are described. Intermittent MSUD is a potentially life-threatening metabolic disorder caused by a deficiency of branched-chain a-keto acid dehydrogenase, the enzyme complex that decarboxylates the 3 branched-chain amino acids. In contrast to classic MSUD, children with the intermittent form show normal development with normal intelligence and, when asymptomatic, normal levels of branched-chain amino acids. Symptoms usually appear between 5 months and 2 years of age, when a trivial infection such as otitis media or viral gastroenteritis triggers catabolism of muscle protein. Intermittent MSUD should be suspected in cases of common infections with a clinically atypical course, especially in children displaying ataxia or marked drowsiness. Pediatrics 2014;133:e458–e460 AUTHORS: Olof Axler, MD, PhDa and Peter Holmquist, MDb aDepartment of Clinical Chemistry, University and Regional Laboratories Region Skåne, Sweden; and bDivision of Endocrinology, Department of Pediatrics, University Hospital Lund, Sweden