UGT1A1 variants in Chinese Uighur and Han newborns and its correlation with neonatal hyperbilirubinemia

Abstract

To explore the correlation between UGT1A1 variant and neonatal hyperbilirubinemia in Chinese Uighur and Han populations. We conducted this study in Urumqi, China. Umbilical cord blood specimens and clinical information of term infants born in the studied center were collected. Variation status of UGT1A1 was determined by direct sequencing or capillary electrophoresis analysis. 102 Uighur and 99 Han normal term neonates, together with 19 hospitalized term newborns (10 Uighur and 9 Han) due to significant hyperbilirubinemia were enrolled into the final analysis. The incidence of neonates with high-risk transcutaneous bilirubin level (TCB) were much higher in Han newborns than in Uighur newborns(P = 0.01). Also, there was statistically significant difference in (TA) 7 promoter mutation of UGT1A1 between Han and Uighur group(χ2 = 4.675, P = 0.03). Furthermore, exon mutation (c.211 and /or c.1091) in UGT1A1 gene was significantly associated with increased TCB level (ORadj = 1.41, 95%CI: 0.25-2.51, P = 0.002) and higher risk of hyperbilirubinemia in both Han and Uighur infants after adjusted for covariates (ORadj = 2.21, 95%CI: 1.09-4.49, P = 0.03). In conclusion, UGT1A1 promoter polymorphism seem to be an important genetic modulator of plasma bilirubin level and neonatal hyperbilirubinemia risk within ethnic groups. Genetic assessment of UGT1A1 coding variants may be useful for clinical diagnosis of neonatal jaundice.

Fig 1. Mutations of UGT1A1 found in our study cohort.

(A) c. 211 G >A heterozygote (Gly71Arg); (B) c. 211 G >A homozygote (Gly71Arg) (C) c.1091C>T heterozygote (Pro364Leu).

Fig 2. A typical chromatograph of capillary electrophoresis of UGT1A1 (TA)n promoter polymorphism followed by direct sequencing.

a(1–2) (TA)6 /(TA)6 homozygote; b(1–2) (TA)6/(TA)7 heterozygote. c(1–2) (TA)7 /(TA)7 homozygote; d(1–2) (TA)5 /(TA)6 homozygote.