Etiology analysis for term newborns with severe hyperbilirubinemia in eastern Guangdong of China.

BACKGROUND: Neonatal hyperbilirubinemia is one of the common diseases of newborns that typically presents with yellow staining of skin, resulting in sequelaes such as hearing loss, motor and intellectual development disorders, and even death. The pathogenic factors of neonatal hyperbilirubinemia are complex. Different cases of hyperbilirubinemia may have a single or mixed etiology. AIM: To explore the etiological characteristics of severe hyperbilirubinemia in term newborns of eastern Guangdong of China. METHODS: 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 term newborns with hyperbilirubinemia in eastern Guangdong of China, 32.20% (580/1602) was severe hyperbilirubinemia. Among the causes of severe hyperbilirubinemia, neonatal hemolysis accounted for 15.17%, breast milk jaundice accounted for 12.09%, infection accounted for 10.17%, glucose-6-phosphate dehydrogenase (G6PD) deficiency accounted for 9.14%, and the coexistence of multiple etiologies accounted for 6.55%, unknown etiology accounted for 41.72%. ABO hemolysis and G6PD deficiency were the most common causes in the 20 cases with bilirubin encephalopathy. 94 severe hyperbilirubinemia newborns were tested for uridine diphosphate glucuronosyl transferase 1A1 (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 in eastern Guangdong of China were the hemolytic disease of the newborns, 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.

Red Blood Cell Membrane-Related Gene Variants and Clinical Risk Factors in Chinese Neonates with Hyperbilirubinemia.

INTRODUCTION: Neonatal hyperbilirubinemia is common and remains a clinical concern in China. Since neonatal hyperbilirubinemia is linked to genetic factors, we aimed to identify the gene variants of the red blood cell membrane (RBCM) and evaluate the clinical risk factors in Chinese neonates with hyperbilirubinemia. METHODS: 117 hyperbilirubinemia neonates (33 cases of moderate hyperbilirubinemia and 84 cases of severe hyperbilirubinemia) and 49 controls with normal bilirubin levels were selected as our study subjects. A customized 22-gene panel with next-generation sequencing (NGS) was designed to characterize genetic variations among the neonates. Sanger sequencing was used to verify the accuracy of the NGS. The clinical risk factors and potential effects of genetic variations in neonates with hyperbilirubinemia were subsequently assessed. RESULTS: After data filtering, suspected pathogenic variants of UGT1A1, SLCCO1B1, and RBCM-associated gene were identified in neonates, the combined numbers of RBCM-associated gene variants were found to have differences between the hyperbilirubinemia group and the controls (p = 0.008), they were also different between severe hyperbilirubinemia and moderate hyperbilirubinemia (p = 0.008), and were correlated with an increased risk of hyperbilirubinemia (odds ratio = 9.644, p = 0.006). The UGT1A1-rs4148323 variant in neonates with hyperbilirubinemia was significantly increased as compared with the controls (p < 0.001). However, there was no statistical difference for the SLCO1B1-rs2306283 variant between the hyperbilirubinemia group and the controls. In addition, breastfeeding contributed to an increased risk of hyperbilirubinemia. CONCLUSION: Our study highlights that the RBCM-related gene variants are an underestimated risk factor, which may play an important role in developing hyperbilirubinemia in Chinese newborns.

Clinical features and genetic variations of severe neonatal hyperbilirubinemia: Five case reports.

BACKGROUND: Neonatal hyperbilirubinemia is a common problem faced by pediatricians. The role of genetic factors in neonatal jaundice has been gradually recognized. This study aims to identify genetic variants that influence the bilirubin level in five patients using next-generation sequencing (NGS). CASE SUMMARY: Five neonates with severe hyperbilirubinemia were retrospectively studied. They exhibited bilirubin encephalopathy, hypothyroidism, ABO blood type incompatibility hemolysis, glucose-6-phosphate dehydrogenase (G6PD) deficiency and premature birth, respectively. A customized 22-gene panel was designed, and NGS was carried out for these neonates. Eight variations (G6PD c.G1388A, HBA2 c.C369G, ABCC2 c.C3825G, UGT1A1 c.G211A, SPTB c.A1729G, EPB41 c.G520A, c.1213-4T>G and c.A1474G) were identified in these five neonates. Genetic mutations of these genes are associated with G6PD deficiency, thalassemia, Dubin-Johnson syndrome, Gilbert syndrome, hereditary spherocytosis, and hereditary elliptocytosis. One of the neonates was found to have compound variants of the EPB41 splice site c.1213-4T>G and c.G520A (p.E174K), but no elliptocyte was seen on his blood smear of 4 years old. CONCLUSION: Pathological factors of severe neonatal hyperbilirubinemia are complicated. Genetic variants may play an important role in an increased risk of neonatal hyperbilirubinemia, and severe jaundice in neonates may be related to a cumulative effect of genetic variants.

UGT1A1*6 mutation associated with the occurrence and severity in infants with prolonged jaundice.

Background: This study aimed to investigate the influence of a variant of the UGT1A1 gene on the occurrence and severity of prolonged jaundice in Chinese infants at term. Methods: 175 infants with prolonged jaundice and 149 controls were used in this retrospective case-control study. The infants with prolonged jaundice were subdivided into the mild-medium and severe jaundice groups (TSB ≥ 342 µmol/L). The frequency and genotype distribution of the UGT1A1 and G6PD genes, and clinical parameters including sex, birth weight, delivery mode, gestational age, and feeding mode, were analyzed, and the differences in the parameters between the two groups were compared. Results: The allele frequency of UGT1A1*6 in the prolonged jaundice group was higher than that in the control group. Similarly, it was also higher in the severe jaundice group than in the mild-medium jaundice group. Homozygous and heterozygous UGT1A1*6 were also found more frequently in the prolonged jaundice group than in the control group. Exclusive breastfeeding, homozygous and heterozygous forms of UGT1A1*6 were significant risk indicators for prolonged jaundice. Moreover, UGT1A1*6 was the best predictor of prolonged severe jaundice. Conclusion: UGT1A1*6 appears to be a risk factor for prolonged jaundice with hyperbilirubinemia in term infants of Chinese ancestry who are exclusively breastfed.

UGT1A1 mutation association with increased bilirubin levels and severity of unconjugated hyperbilirubinemia in ABO incompatible newborns of China.

BACKGROUND: Neonatal hyperbilirubinemia causing jaundice is common in East Asian population. Uridine diphosphate glucuronosyltransferase isoenzyme (UGT1A1) glucuronidates bilirubin and converts the toxic form of bilirubin to its nontoxic form. METHOD: A retrospective study was conducted to review clinical information of ABO hemolysis neonates (ABO HDN) admitted to the Department of Neonatology, referred for neonatal hyperbilirubinemia, in a large general hospital of southern China from 2011 to 2017. Variation status of UGT1A1 was determined by direct sequencing or genotype assays. RESULT: Sixty-nine ABO HDNs were included into the final analysis. UGT1A1 c.211 G > A mutation (UGT1A1*6, p.Arg71Gly, rs4148323) was significantly associated with the increased bilirubin level in ABO HDNs, after adjusted by age, sex and feeding method (P = 0.019 for TBIL, P = 0.02 for IBIL). Moreover, heterozygous and/or homozygous UGT1A1 mutations in the coding sequence region were significantly associated with the increased risk of developing hazardous hyperbilirubinemia (as defined by TSB > 427 umol/L) as compared those with a normal UGT1A1 genotype (ORadj = 9.16, 95%CI 1.99-42.08, P = 0.002) in the study cohort. CONCLUSION: UGT1A1 variant in coding region is actively involved in the pathogenesis of ABO hemolysis related neonatal hyperbilirubinemia. Genetic assessment of UGT1A1 may be useful for clinical diagnosis of neonatal unconjugated hyperbilirubinemia.