Etiology analysis for full-term newborns with severe hyperbilirubinemia in eastern Guangdong

Objective To explore the etiological characteristics of severe hyperbilirubinemia in full-term newborns of eastern Guangdong. Methods Full-term newborns with severe hyperbilirubinemia in one hospital from January 2012 to December 2021 were retrospectively analyzed. The etiology was determined according to the laboratory results and clinical manifestations. Results Among 1602 full-term newborns with hyperbilirubinemia in Chaozhou area, 32.20% (580/1602) was severe hyperbilirubinemia, including 213 newborns with TSB levels reaching the recommended exchange transfusion levels and 52 cases diagnosed with prolonged jaundice. Among the causes of severe hyperbilirubinemia, neonatal hemolysis accounted for 15.17%, infection accounted for 10.17%, G6PD deficiency accounted for 9.13%, and the coexistence of multiple etiologies accounted for 6.55%, unknown etiology accounted for 50.00%. ABO hemolysis and G6PD deficiency were the most common causes in the 20 cases with bilirubin encephalopathy. 94 severe hyperbilirubinemia newborns were tested for UGT1A1*6 variant (rs4148323, c.211G > A, p.Arg71Gly,), 9 cases were 211 G to A homozygous variant, 37 cases were 211 G to A heterozygous variant, and 48 cases were wild genotypes. Conclusion The main cause for severe hyperbilirubinemia and bilirubin encephalopathy were the hemolytic disease of the newborn, G6PD deficiency and infection. UGT1A1 gene variant was also a high risk factor for neonatal hyperbilirubinemia. Targeted prevention and treatment according to the etiology may reduce the occurrence of bilirubin encephalopathy and kernicterus.