Editor—A variant TATA box (A[TA]₇TAA, designated as TA-7) in the promoter region of the bilirubin UDP-glucuronosyltransferase 1 (BUGT1) gene has been reported to accelerate the increase in bilirubin concentration during the first two days of life.1 However, the relation between TA-7 and peak bilirubin concentration in the neonatal period has not been clarified, and it is also unclear as to whether TA-7 influences bilirubin metabolism in infants of different ethnic groups.

To investigate whether TA-7 is one of the risk factors for neonatal jaundice in the Japanese population, we performed genotyping analysis of the BUGT1 gene in 74 Japanese newborn infants, and measured bilirubin concentrations at 4–5 days of age in healthy infants (n=55) and peak bilirubin concentrations in infants with jaundice requiring treatment, phototherapy, or exchange transfusion (n=19). …