ABSTRACT
Maple syrup urine disease(MSUD) is an autosomal recessive disorder involving the metabolism of the branched-chain amino acids(BCAA) such as leucine, isoleucine and valine. The disorder is due to a defect in branched-chain alpha-ketoacid dehydrogenase(BCKAD) and the classic form causes rapid progressive and overwhelming illness beginning in the first weeks of life, present with poor feeding, lethargy, change in muscle tone, acidosis, seizures and coma. The goal of therapy in acutely ill patients with MSUD is an immediate reduction in the plasma levels of the BCAAs and branched-chain ketoacids. In this report, we describe an infant with MSUD who was treated by dietary therapy alone. During the therapy, acrodermatitis enteropathica-like syndrome developed with low plasma isoleucine concentration while she was receiving a formula deficient in BCAAs.