Neonatal Mass‐Screening for Inborn Errors of Metabolism in Japan

Abstract This report describes the results of neonatal mass screening in Japan for PKU, maple syrup urine disease, histidinemia, homocystinuria, galactosemia, inborn errors of urea cycle metabolism and congenital hypothyroidism. The incidence of PKU is low but the incidence of histidinemia is somewhat high compared to that in the United States. Some genetic variants of each of these inborn errors of metabolism such as malignant hyperphenylalaninemia or mild form of MSUD have been detected in the neonatal screening. Clinical values of the screening for each of these in born errors of metabolism are discussed.