Identification of Genetic Risk Factors for Neonatal Hyperbilirubinemia in Fujian Province, Southeastern China: A Case-Control Study

Associations between UGT1A1, SLCO1B1, SLCO1B3, BLVRA and HMOX1 polymorphisms and susceptibility to neonatal severe hyperbilirubinemia in Chinese Han population

BACKGROUND

Severe neonatal hyperbilirubinemia could lead to kernicterus and neonatal death. This study aimed to analyze the association between single nucleotide polymorphisms in genes involved in bilirubin metabolism and the incidence of severe hyperbilirubinemia.

METHODS

A total of 144 neonates with severe hyperbilirubinemia and 50 neonates without or mild hyperbilirubinemia were enrolled in 3 institutions between 2019 and 2020. Twelve polymorphisms of 5 genes (UGT1A1, SLCO1B1, SLCO1B3, BLVRA, and HMOX1) were analyzed by PCR amplification of genomic DNA. Genotyping was performed using an improved multiplex ligation detection reaction technique based on ligase detection reaction.

RESULTS

The frequencies of the A allele in UGT1A1-rs4148323 and the C allele in SLCO1B3-rs2417940 in the severe hyperbilirubinemia group (30.2% and 90.6%, respectively) were significantly higher than those in the controls (30.2% vs.13.0%, 90.6% vs. 78.0%, respectively, both p < 0.05). Haplotype analysis showed the ACG haplotype of UGT1A1 were associated with an increased hyperbilirubinemia risk (OR 3.122, p = 0.001), whereas the GCG haplotype was related to a reduced risk (OR 0.523, p = 0.018).

CONCLUSION

The frequencies of the A allele in rs4148323 and the C allele in rs2417940 are highly associated with the incidence of severe hyperbilirubinemia in Chinese Han neonates.

TRIAL REGISTRATION

Trial registration number:ChiCTR1800020424; Date of registration:2018-12-29.

G6PD gene detection in neonatal hyperbilirubinemia and analysis of related risk factors

BACKGROUND

Hyperbilirubinemia is a common disorder in neonates, with premature infants at higher risk of developing the disorder.

OBJECTIVE

Glucose-6-phosphate dehydrogenase (G6PD) gene detection was used to determine the incidence of G6PD deficiency and analyze the etiologies of G6PD deficiency in neonates with hyperbilirubinemia in the Zunyi region with the aim of providing scientific evidence for the clinical diagnosis and treatment.

METHODS

For the gene detection, 64 neonates with hyperbilirubinemia were selected as the observation group and 30 normal neonates were selected as the control group, and the risk factors for hyperbilirubinemia were investigated by using multivariate logistic regression analysis.

RESULTS

Among the neonates in the observation group, 59 cases had the G1388A mutation (92.19%) and 5 cases had the G1376T mutation (7.81%). No mutation was detected in the control group. In the observation group, the proportion of neonates who were born prematurely, with artificial feeding, with the age of starting feeding of more than 24 h, the time of first bowel movement of more than 24 h, premature rupture of membranes, infection, scalp hematoma, and perinatal asphyxia was higher than that in the control group, and the difference was statistically significant (p< 0.05). Multivariate logistic regression analysis showed that prematurity, infection, scalp hematoma, perinatal asphyxia, the age of starting feeding of more than 24 h, and the time of first bowel movement over 24 h were risk factors for the development of neonatal hyperbilirubinemia (p< 0.05).

CONCLUSION

The G1338A and G1376T mutations were important features of the genetics of neonatal hyperbilirubinemia, and genetic detection together with the prevention of prematurity, infection, scalp hematoma, perinatal asphyxia, the age of starting feeding, and the time of first bowel movement would help reduce the incidence of this disease.

Prevalence and association of early onset severe hyperbilirubinemia in newborn in the East China region: Retrospective medical record analyses

Research on the prevalence and association of hyperbilirubinemia is controversial because of different cultures, demographics, and clinical conditions. The etiology of hyperbilirubinemia is affected by the environment and other factors in the newborn. The World Health Organization recommended a 1-day hospital stay after uncomplicated delivery, jaundice assessment before discharge, and screening on 3rd and 7th days after birth for hyperbilirubinemia. However, the implementation of these recommendations is difficult in China. The objective of this study was to evaluate the prevalence and association of early onset severe hyperbilirubinemia in newborns in East China. Retrospective medical record analyses for 250 cesarean sections or vaginal deliveries, ≥2 kg body weight, and negative for Hepatitis B surface antigen by birth newborns were performed. A biochemical analyzer, quantitative assay, and quantitative polymerase chain reaction were used to evaluate total serum bilirubin, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and gene variant phenotyping, respectively. A total in 33 (13%) newborns were reported with early onset severe hyperbilirubinemia (according to the American Academy of Pediatrics, total serum bilirubin ≥ 342 μmol/L within 6 hours of birth). All newborns with severe hyperbilirubinemia were hospitalized and underwent phototherapy. The mothers of all newborns had a gestational age ≥ 35 weeks. Hospitalization included artificial feeding, and breastfeeding was rare (P < .0001). ABO incompatibility ("O" blood type for mother and either "A" or "AB" or "B" blood type for newborn, P = .0411), G6PD deficiency (G6PD/6-phosphogluconate dehydrogenase ≤ 1.0 in quantitative assay, P = .0422), Rh incompatibility (the mother's blood type was Rh negative and newborn blood type was Rh positive, P = .0416), fewer genotype rs4149056 frequencies (P = .0452), higher genotype rs2306283 frequencies (P = .0461), and higher genotype rs1805173 frequencies (P = .0471) were independent parameter for early onset severe hyperbilirubinemia of newborns. The prevalence of early onset severe hyperbilirubinemia in Chinese newborns is 13% in the East China region. Blood incompatibility, G6PD deficiency, fewer genotype rs4149056 frequencies, higher genotype rs2306283 frequencies, and higher genotype rs1805173 frequencies were independent predictors of early onset severe hyperbilirubinemia among newborns in the East China region (Level of Evidence: IV; Technical Efficacy: Stage 5).

Etiology analysis and G6PD deficiency for term infants with jaundice in Yangjiang of western Guangdong

Objective

Glucose 6-phosphate dehydrogenase (G6PD) deficiency increases the risk of neonatal hyperbilirubinemia. The aim of this study is to evaluate the risk factors associated with hyperbilirubinemia in infants from the western part of Guangdong Province, and to assess the contribution of G6PD deficiency to neonatal jaundice.

Methods

The term infants with neonatal hyperbilirubinemia in People's Hospital of Yangjiang from June 2018 to July 2022 were recruited for the retrospective analysis. All the infants underwent quantitative detection of the G6PD enzyme. The etiology was determined through laboratory tests and clinical manifestations.

Results

Out of 1,119 term infants, 435 cases presented with jaundice. For the etiology analysis, infection was responsible for 16.09% (70/435), G6PD deficiency accounted for 9.66% (42/435), of which 3 were complicated with acute bilirubin encephalopathy), bleeding accounted for 8.05% (35/435), hemolytic diseases accounted for 3.45% (15/435), and breast milk jaundice accounted for 2.53% (11/435). One case (0.23%) was attributed to congenital hypothyroidism, multiple etiologies accounted for 22.3% (97/435), and 35.63% (155/435) were of unknown etiology. Of the jaundiced infants, 19.54% (85/435) had G6PD deficiency, while only 10.23% (70/684) of non-jaundiced infants had G6PD deficiency; this difference was found to be statistically significant (P < 0.001). Furthermore, the hemoglobin levels in the jaundiced infants with G6PD deficiency (146.85 ± 24.88 g/L) were lower than those without G6PD deficiency (156.30 ± 22.07 g/L) (P = 0.001). 65 jaundiced infants with G6PD deficiency underwent G6PD mutation testing, and six different genotypes were identified, including c.95A > G, c.392G > T, c.1024C > T, c.1311C > T, c.1376G > T, c.1388G > A, c.871G > A/c.1311C > T, c.392G > T/c.1388G > A, and c.1376G > T/c.1311C > T.65iciency.

Conclusion

In newborns in Yangjiang, G6PD deficiency, infection, and neonatal hemolytic disease were identified as the main causes of hyperbilirubinemia and acute bilirubin encephalopathy. Specifically, Hemolytic factors in infants with G6PD deficiency may lead to reduced hemoglobin and increased bilirubin levels in jaundiced infants.

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.

Contribution of genetic factors to high rates of neonatal hyperbilirubinaemia on the Thailand-Myanmar border

Very high unconjugated bilirubin plasma concentrations in neonates (neonatal hyperbilirubinaemia; NH) may cause neurologic damage (kernicterus). Both increased red blood cell turn-over and immaturity of hepatic glucuronidation contribute to neonatal hyperbilirubinaemia. The incidence of NH requiring phototherapy during the first week of life on the Thailand-Myanmar border is high (approximately 25%). On the Thailand-Myanmar border we investigated the contribution of genetic risk factors to high bilirubin levels in the first month of life in 1596 neonates enrolled in a prospective observational birth cohort study. Lower gestational age (<38 weeks), mutations in the genes encoding glucose-6-phosphate dehydrogenase (G6PD) and uridine 5'-diphospho-glucuronosyltransferase (UGT) 1A1 were identified as the main independent risk factors for NH in the first week, and for prolonged jaundice in the first month of life. Population attributable risks (PAR%) were 61.7% for lower gestational age, 22.9% for hemi or homozygous and 9.9% for heterozygous G6PD deficiency respectively, and 6.3% for UGT1A1*6 homozygosity. In neonates with an estimated gestational age ≥ 38 weeks, G6PD mutations contributed PARs of 38.1% and 23.6% for "early" (≤ 48 hours) and "late" (49-168 hours) NH respectively. For late NH, the PAR for UGT1A1*6 homozygosity was 7.7%. Maternal excess weight was also a significant risk factor for "early" NH while maternal mutations on the beta-globin gene, prolonged rupture of membranes, large haematomas and neonatal sepsis were risk factors for "late" NH. For prolonged jaundice during the first month of life, G6PD mutations and UGT1A1*6 mutation, together with lower gestational age at birth and presence of haematoma were significant risk factors. In this population, genetic factors contribute considerably to the high risk of NH. Diagnostic tools to identify G6PD deficiency at birth would facilitate early recognition of high risk cases.

Molecular Genetic Screening of Neonatal Intensive Care Units: Hyperbilirubinemia as an Example

Objective

To explore the clinical value of newborn genomic screening (nGS) for neonatal intensive care units (NICU) infants (taking neonatal hyperbilirubinemia as an example).

Methods

Dried blood spots (DBSs) were collected after 72 hours of birth. The tandem mass spectrometry (TMS) screening and Angel Care genomic screening (GS, based on Targeted next-generation sequencing) were performed at the same time.

Results

Ninety-six hyperbilirubinemia newborns were enrolled in this study and none was identified with inborn errors of metabolism (IEM) by TMS, while 6 infants (6.25%, 6/96) were suspected to have a genetic disorder by Angel Care, including 2 cases of glucose-6-phosphate dehydrogenase deficiency (G6PD), and 1 case of maple syrup urine disease type 1B (MSUD1B), autosomal recessive deafness 1A (DFNB1A), Leber hereditary optic neuropathy (LHON), thyroid dyshormonogenesis 6 (TDH6) each. In addition, 44 infants (45.8%) were detected having at least one variant which conferred a carrier status for a recessive childhood-onset disorder. A total of 33 out of 60 variants (55.0%) reported for carrier status were pathogenic (P), 24 (40.0%) were likely pathogenic (LP), and 3 variants were variant of uncertain significance (VUS). Top six common genes of carrier status were GJB2, DUOX2, PRODH, ATP7B, SLC12A3, SLC26A4. Two newborns showed abnormalities in elementary screening of TMS, but were confirmed as false positive after recall. Their results of Angel Care did not found abnormality.

Conclusion

Using neonatal hyperbilirubinemia as an example, genome sequencing screening can find more evidence of genetic variation in NICU newborns, and “Angel Care” is an effective method.

Compound heterozygous UGT1A1*28 and UGT1A1*6 or single homozygous UGT1A1*28 are major genotypes associated with Gilbert's syndrome in Chinese Han people

Gilbert's syndrome (GS) is a mild condition characterized by periods of hyperbilirubinemia, which results in variations in the UDP-glucuronosyltransferase 1 (UGT1A1) gene. Variant genotypes of UGT1A1 vary in different populations in the world. The present study aimed to determine the genotype of the UGT1A1 promoter and exon that are related to the serum total bilirubin (STB) level in the Chinese Han population. A total of 120 individuals diagnosed with GS (GS group) and 120 healthy individuals (non-GS group) were enrolled. Routine blood, liver function tests, and antibodies associated with autoimmune liver diseases were assessed. Blood samples were collected for DNA purification. Sequencing of the UGT1A1 promoter and exons was conducted for post segment amplification by PCR. Compound heterozygous UGT1A1*28 and UGT1A1*6 (25/120, 20.83%), single homozygous UGT1A1*28 (24/120, 20.00%) and single heterozygous UGT1A1*6 (18/120, 15.00%) were the most frequent genotypes in the GS group. However, single heterozygous UGT1A1*6 (30/120, 25.00%) and single heterozygous UGT1A1*28 (19/120, 15.83%) were the most frequent genotypes in the non-GS group. Further, the frequencies of single homozygous UGT1A1*28, compound heterozygous UGT1A1*28 and UGT1A1*6, and compound heterozygous UGT1A1*28, UGT1A1*6 and UGT1A1*27 were significantly higher in the GS group than those in the non-GS group. The STB levels of GS patients with the homozygous UGT1A1*28 genotype were remarkably higher than those of patients with other genotypes. Homozygous UGT1A1*28 and heterozygous UGT1A1*6 variants were associated with the highest and lowest risks of hyperbilirubinemia, respectively. Our study revealed that compound heterozygous UGT1A1*28 and UGT1A1*6, or single homozygous UGT1A1*28 are major genotypes associated with GS in Chinese Han people. These findings might facilitate the precise genomic diagnosis of Gilbert's syndrome.

[Research advances in neonatal hyperbilirubinemia and gene polymorphisms]

Hyperbilirubinemia is a prevalent disease in neonates and is also a main reason for hospitalization within the first week after birth, and this disease is mainly caused by the imbalance between production and elimination of bilirubin. Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1), organic anion transporter polypeptide 2 (OATP2), heme oxygenase 1 (HO-1), and biliverdin reductase A (BLVRA) play crucial roles in the metabolism of bilirubin. More and more studies have revealed the association between the variation of the encoding genes for these enzymes and hyperbilirubinemia. This article reviews the research advances in the association between the gene polymorphisms of bilirubin metabolic enzymes and hyperbilirubinemia.

SLCO1B1 c.388A > G variant incidence and the severity of hyperbilirubinemia in Indonesian neonates

OBJECTIVE

It has been established that genetic factors play a substantial role in the development of neonatal hyperbilirubinemia. The population of Indonesia and other Southeast Asian countries has similar, yet different genetic makeup compared to the rest of Asia. Aside from UGT1A1, variants of SLCO1B1 have also been known to contribute to the severity of neonatal hyperbilirubinemia in Asian populations. Since there has been no report on SLCO1B1 polymorphism in relation with hyperbilirubinemia in Indonesia, this study aims to explore incidence of SLCO1B1*1B polymorphism in Indonesia based on 3 hospitals from different provinces and population, and their association with hyperbilirubinemia severity.

METHODS

Our study included 88 neonates with mild and moderate-severe hyperbilirubinemia from 3 NICU in hospitals representing homogenous and heterogenous populations: Biak General Hospital Papua, Cipto Mangunkusumo Hospital (Jakarta), and M Yunus Hospital (Bengkulu). We collected samples between November 2016 and September 2017. DNA was obtained from existing samples of the patients from previous studies and were subjected to Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR-RFLP). We analyzed the *1B variant located in exon 5 of SLCO1B1 with TaqI restriction endonuclease. Clinical, demographic, and laboratory data was also collected from medical records and parents' interviews.

RESULTS

The most dominant variant of SLCO1B1*1B in our population is the homozygous G/G (68.18%), followed by heterozygous A/G (26.14%), and wild type A/A (5.68%). The heterozygous A/G had an Odds Ratio (OR) of 0.73 (95% CI 0.10-5.2) and homozygous G/G with OR of 0.51 (95%CI 0.08-3.27), both were not significant. Genotypic distribution across the different centers were also similar and not significant. The significant risk factors for moderate-severe hyperbilirubinemia were the population the neonate originated from (p = < 0.001) and the delivery location (p = 0.001), while SLCO1B1*1B was not associated with the different severity of hyperbilirubinemia.

CONCLUSIONS

SLCO1B1*1B is not associated with higher bilirubin levels among neonates with hyperbilirubinemia in Indonesia. Further study is needed to find other potentially important genetic polymorphisms in the development of severe hyperbilirubinemia in Indonesia.