Interaction of coding region mutations and the Gilbert-type promoter abnormality of the UGT1A1 gene causes moderate degrees of unconjugated hyperbilirubinaemia and may lead to neonatal kernicterus

Because the expression of one structurally normal allele is sufficient to keep serum bilirubin levels within normal limits, heterozygous carriers are not expected to have hyperbilirubinaemia. Three of the structural mutations are being reported here for the first time.\n Thus, approximately 51% of the general population carry a Gilbert-type promoter on at least one allele. [...]heterozygous carriers of a structural mutation of UGT1A1 (CN1 or CN2 type) have a relatively high probability of carrying a Gilbert-type promoter on the normal allele.