Complex multifactorial nature of significant hyperbilirubinemia in neonates.
OBJECTIVE
To determine whether glucose-6-phosphate dehydrogenase (G6PD), uridine-diphosphoglucuronosyltransferase 1A1 (UGT1A1), and hepatic solute carrier organic anion transporter 1B1 (SLCO1B1) gene variants occur at greater frequency in neonates with significant hyperbilirubinemia.


METHODS
Infants with gestational ages of >or=37 weeks and ages of <7 days were studied. Case subjects had >or=1 bilirubin level above the 95th percentile (high-risk zone), whereas control subjects had bilirubin levels of <40th percentile (low-risk zone) at study entry.


RESULTS
A total of 153 case subjects (median bilirubin level: 15.7 mg/dL) and 299 control subjects (median bilirubin level: 4.6 mg/dL) were evaluated. There were no statistical differences in the frequencies of G6PD, UGT1A1, and SCLO1B1 gene variants between case and control subjects (G6PD: 5.2% vs 3.3%; UGT1A1: 14.4% vs 9.4%; SLCO1B1: 73.2% vs 73.6%). However, coexpression of the G6PD African A- mutation with UGT1A1 and/or SLCO1B1 variants was seen more frequently for case subjects. Case subjects more often demonstrated >or=2 factors contributing to hyperbilirubinemia, including ABO blood group heterospecificity in which the mother had blood group O (47.7% vs 11.4%), positive direct Coombs test results (33.3% vs 4%), sibling treated with phototherapy (16.3% vs 5.4%), maternal circulating blood group antibodies (10.5 vs 0.7%), maternal diabetes mellitus (13.1% vs 6.4%), and maternal East Asian ethnicity (6.5% vs 1.3%).


CONCLUSIONS
Clinical contributors to hyperbilirubinemia were identified more frequently for case subjects but individually G6PD, UGT1A1, and SLCO1B1 variants were not. Coexpression of the G6PD African A- mutation with UGT1A1 and SLCO1B1 variants was seen more often for case subjects.
Watchko
Jon F
JF
Division of Newborn Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Lin
Zhili
Z
Clark
Reese H
RH
Kelleher
Amy S
AS
Walker
M Whit
MW
Spitzer
Alan R
AR
D005260:Female; D005787:Gene Frequency; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics*; D014453:Glucuronosyltransferase / Q000235:genetics*; D006801:Humans; D051556:Hyperbilirubinemia, Neonatal / Q000209:etiology / Q000235:genetics*; D007231:Infant, Newborn; D027381:Liver-Specific Organic Anion Transporter 1; D008297:Male; D009154:Mutation; D027361:Organic Anion Transporters / Q000235:genetics*; D011110:Polymorphism, Genetic; D000099148:UGT1A1 Enzyme
D005954:Glucosephosphate Dehydrogenase; D014453:Glucuronosyltransferase; D027381:Liver-Specific Organic Anion Transporter 1; D027361:Organic Anion Transporters; D000099148:UGT1A1 Enzyme; C503999:SLCO1B1 protein, human