In this issue of AJDC, Giacoia and Berry1 report the occurrence of an acrodermatitis enteropathica (AE)–like eruption in an infant with maple syrup urine disease (MSUD) while being fed an isoleucine-deficient formula. At least two important points emerge from this observation.
The first point is the importance of providing necessary amounts of essential amino acids when infants with metabolic disorders are fed intravenously or fed special formulas. Total restriction of phenylalanine is not possible in phenylketonuria, and total restriction of branched-chain amino acids (BCAAs) is deleterious in MSUD as suggested by Giacoia and Berry. Recently, a more extensive cutaneous eruption was reported in an infant with MSUD in whom inadequate amino acid intake was associated with severely depressed levels of all three BCAAs (valine, leucine, and isoleucine).2 The authors of the second report contend that clinical differences (total body exfoliative dermatitis without mucous