OBJECTIVENeonatal unconjugated hyperbilirubinemia is one of the most common conditions encountered by the practicing pediatricians. Although it is usually self-limited and benign, the condition is of importance because of the rare instances in which severe hyperbilirubinemia can lead to bilirubin encephalopathy or kernicterus. The uridine diphosphate-glucuronosyl transferase 1A1 (UGT 1A1) gene controls bilirubin conjugation by determining the structure of the enzyme glucuronosyltransferase, which is synthesized in the hepatocyte. In the recent years much has been learned about the relationship between UGT 1A1 gene mutation and neonatal hyperbilirubinemia. This study aimed to investigate the roles of UGT 1A1 gene mutation in the development of neonatal hyperbilirubinemia in Guangxi.

METHODSA total of 73 cases with hyperbilirubinemia and 31 healthy neonates were enrolled. UGT 1A1 G71R genotypes were identified by the (amplification refractory mutation system, ARMS) and direct sequencing method in all the neonates. To analyze the incidence of bilirubin encephalopathy, the peak (total serum bilirubin, TSB) concentration after 72 hours of age, and the possibility of TSB > 20 mg/dl of each group.

RESULTS(1) The frequencies of allele G71R were 0.1915 in this study, 0.2329 in hyperbilirubinemia group vs. 0.097 in healthy groups. The allele gene frequency of G71R in neonatal hyperbilirubinemia was higher than that in the normal group (P < 0.05). (2) Homozygous neonates had higher possibility to develop bilirubin encephalopathy and higher TSB concentration 72 hours after birth (28.57%, 23.12 ± 4.58) than the normal group (0%, 17.68 ± 2.69). The difference between the former two was significant (P < 0.001). (3) The TSB of the 5 neonates was > 20 mg/dl in G71R homozygous type, the odds ratio and 95%CI were 7.955 (1.349, 46.899).

CONCLUSION(1) G71R mutation gene was associated with neonatal jaundice in Guangxi region. (2) The possibility of TSB > 20 mg/dl in G71R homozygous was higher than those of the wild-type. (3) The incidence of bilirubin encephalopathy and TSB concentration after 72 hours of age for neonates who were homozygous to G71R gene were higher than the wild-type.