1029 Polymorphic Variants of Ugt1A1 in Neonatal Jaundice in Southern Brazil

Abstract

Background and aims: Neonatal jaundice seems a benign condition but babies must be monitored in order to identify those who are at higher risk of encephalopathy. Abnormalities in hepatic conjugation of bilirubin were proposed in those cases - polymorphisms of the hepatic enzyme UGT1A1. Herein, we estimated the frequency of alleles and of genotypes of the promoter region of UGT1A1 gene in newborns and evaluated its association with severe hyperbilirubinemia.

Methods: Case-control study, including all neonates who were in phototherapy at NICU/HCPA from March to December 2007, born > 35w of gestational age and weight > 2000g. Controls were neonates not jaundiced. Informed consent form applied. PCR performed and analyzed in GeneMapper® program.

Results (490 NBs included): There were 7 of the 10 possible UGT1A1 genotypes identified; those related to Gilbert's syndrome were in 16%. Prevalence of polymorphic genotypes in icteric patients was 13.5% and in normal patients was 18.2%, p=0.08. In 86.6% of white neonates - lowrisk genotypes, 13.4%, Gilbert's genotypes, while among blacks, 34% showed the latter genotypes, and 76%, low-risk (p=0.001).

Conclusions: In the present sample the presence of polymorphic variants of UGT1A1 could not be associated to severe hyperbilirubinemia. Variants showed allelic prevalence and frequencies similar to those observed in other populations, with a highlight to the genotypes of higher risk in blacks and mulattos. Possibly due to the high miscegenation found in our state, other factors and genic interactions should be sought in order to explain severe neonatal hyperbilirubinemia, including the study of other polymorphisms.

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