Acrodermatitis enteropathica-like syndrome secondary to isoleucine deficiency during treatment of maple syrup urine disease.

We describe a patient with maple syrup urine disease in whom an acrodermatitis enteropathica-like syndrome developed while he was receiving a branched-chain amino acid-free formula. Iatrogenically induced isoleucine deficiency developed and resulted in a decreased protein accretion and persistent increase in the plasma concentrations of leucine. A rapid clinical response to isoleucine supplementation was noted. This observation underscores the risks of using amino acid-free formulas without adequate supplementation of deficient amino acids.