Association between glucose-6-phosphate dehydrogenase deficiency and neonatal jaundice: interaction with multiple risk factors

Association of gestational hepatitis B virus infection and antiviral therapy with pregnancy outcomes: A retrospective study

OBJECTIVE

To explore the relationships between gestational hepatitis B virus (HBV) infection, antiviral therapy, and pregnancy outcomes.

METHODS

We retrospectively selected hepatitis B surface antigen (HBsAg)-positive pregnant women hospitalized for delivery at Fujian Medical University Affiliated Hospital from October 1, 2016 to October 1, 2020. The control group included randomly selected healthy pregnant women hospitalized for delivery during the same time.

RESULTS

Overall, 1115 participants were enrolled and grouped into control (n = 380) and HBsAg-positive groups (n = 735), which were further divided into groups I (n = 407; low viral load), II (n = 207; high viral load without antiviral therapy), and III (n = 121; high viral load with antiviral therapy). Pregnant women with HBV were positively correlated with the incidence of intrahepatic cholestasis of pregnancy (ICP) (adjusted odds ratio [aOR] 5.1, 95% confidence interval [CI] 2.62-9.92, P < 0.001), neonatal jaundice (aOR 10.56, 95% CI 4.49-24.83, P < 0.001), and neonatal asphyxia (aOR 5.03, 95% CI 1.46-17.27, P = 0.01). Aspartate aminotransferase (AST) greater than the upper limit of normal (ULN) was an independent risk factor for increased ICP incidence (aOR 3.49, 95% CI 1.26-9.67, P = 0.019). Antiviral therapy considerably reduced HBV DNA and improved liver function. High viral load and antiviral therapy did not correlate significantly with adverse pregnancy outcomes (P < 0.05).

CONCLUSION

Pregnant women with HBV have significantly elevated incidence of ICP, neonatal jaundice, and neonatal asphyxia not significantly correlated with viral load. AST greater than ULN independently increases the risk of ICP. Antiviral therapy effectively reduces viral replication and improves liver function without increasing the risk of adverse outcomes.

Preventive effect of prenatal maternal oral probiotic supplementation on neonatal jaundice (POPS Study): A protocol for the randomised double-blind placebo-controlled clinical trial

INTRODUCTION

Neonatal jaundice is a common and life-threatening health problem in neonates due to overaccumulation of circulating unconjugated bilirubin. Gut flora has a potential influence on bilirubin metabolism. The infant gut microbiome is commonly copied from the maternal gut. During pregnancy, due to changes in dietary habits, hormones and body weight, maternal gut dysbiosis is common, which can be stabilised by probiotics supplementation. However, whether probiotic supplements can reach the baby through the mother and reduce the incidence of neonatal jaundice has not been studied yet. Therefore, we aim to evaluate the effect of prenatal maternal probiotic supplementation on the incidence of neonatal jaundice.

METHODS AND ANALYSIS

This is a randomised double-blind placebo-controlled clinical trial among 94 pregnant women (47 in each group) in a tertiary hospital in Hong Kong. Voluntary eligible participants will be recruited between 28 and 35 weeks of gestation. Computer-generated randomisation and allocation to either the intervention or control group will be carried out. Participants will take either one sachet of Vivomixx (450 billion colony-forming units per sachet) or a placebo per day until 1 week post partum. Neither the study participants nor researchers will know the randomisation and allocation. The intervention will be initiated at 36 weeks of gestation. Neonatal bilirubin level will be measured to determine the primary outcome (hyperbilirubinaemia) while the metagenomic microbiome profile of breast milk and maternal and infant stool samples as well as pregnancy outcomes will be secondary outcomes. Binary logistic and linear regressions will be carried out to assess the association of the microbiome data with different clinical outcomes.

ETHICS AND DISSEMINATION

Ethics approval is obtained from the Joint CUHK-NTEC Clinical Research Ethics Committee, Hong Kong (CREC Ref: 2023.100-T). Findings will be published in peer-reviewed journals and presented at international conferences.

TRIAL REGISTRATION NUMBER

NCT06087874.

Effects of a Smartphone-Based Out-of-Hospital Screening App for Neonatal Hyperbilirubinemia on Neonatal Readmission Rates and Maternal Anxiety: Randomized Controlled Trial

Background

Neonatal hyperbilirubinemia is one of the leading causes of neonatal readmission—especially severe hyperbilirubinemia and its complications—and it influences disease burden as well as neonatal and maternal health. Smartphones have been shown to have satisfactory accuracy in screening neonatal bilirubin levels, but the impact of this technology on neonatal health care service and maternal health outcomes is still unknown.

Objective

The aim of this study was to evaluate the impact of a smartphone-based out-of-hospital neonatal jaundice screening program on neonatal readmission rates for jaundice and related maternal anxiety.

Methods

This was a 2-arm, unblinded, randomized controlled trial with 30 days of intervention and follow-up periods. From August 2019 to August 2020, healthy mother-infant dyads were recruited on-site from 3 public hospitals in Hainan, China. Intervention group mothers used the smartphone app to routinely monitor neonatal jaundice at home under the web-based guidance of pediatricians. Control group participants received routine care. The primary study outcome was the neonatal readmission rate due to jaundice within 30 days of the first hospital discharge. The secondary outcome was the maternal anxiety score associated with neonatal jaundice. The data were collected through a self-assessed questionnaire. All participants were included in the analysis (intention-to-treat).

Results

In this study, 1424 mother-infant dyads were recruited, comprising 1424 mothers and 1424 newborns. The median age of the mothers was 29 (IQR 26-32) years, and there were 714 (50.1%) male neonates. These mother-infant dyads were randomly assigned to the intervention group and the control group, with 712 dyads in each group; only 1187 of these dyads completed the follow-up. We found that the adjusted 30-day neonatal readmission rate due to jaundice reduced by 10.5% (71/605, 11.7% vs 141/582, 24.2%; 95% CI 5%-15.9%; odds ratio 0.4, 95% CI 0.3-0.5; P<.001) and the relevant maternal anxiety mean score decreased by 3.6 (95% CI –4.4 to –2.8; β=–3.6, 95% CI –4.5 to –2.8; P<.001) in the intervention group compared to those in the routine care group.

Conclusions

Our study shows that the smartphone-based out-of-hospital screening method for neonatal hyperbilirubinemia decreased the neonatal readmission rate within 30 days from the first discharge and improved maternal mental health to some degree, thus demonstrating the usefulness of this screening app for follow-up in pediatric care.

Trial Registration

China Clinical Trial Registration Center, ChiCTR2100049567; http://www.chictr.org.cn/showproj.aspx?proj=64245

Risk factors for neonatal hyperbilirubinemia: a systematic review and meta-analysis

BACKGROUND

Hyperbilirubinemia is the most common cause of neonatal hospitalization and, although it generally has a good prognosis, a significant percentage of neonatal patients maintain a high bilirubin level, which can lead to severe complications, including lifelong disability such as growth retardation, encephalopathy, autism and hearing impairment. The study of risk factors for neonatal hyperbilirubinemia has been controversial. Therefore, we evaluated the risk factors of neonatal hyperbilirubinemia using a meta-analysis.

METHODS

Relevant English and Chinese studies that discussed risk factors for neonatal hyperbilirubinemia were retrieved from the PubMed, EMBASE, Medline, Central, China National Knowledge Infrastructure (CNKI), Wanfang and China Science Digital Library (CSDL). The literature took newborns as the research object, set up a control group, and observed the relationship between exposure factors and neonatal hyperbilirubinemia. The combined effect size was expressed by odds ratio (OR) and 95% confidence interval (CI). The Chi-square test was used to test heterogeneity of the studies, and if it existed, subgroup analyses were used to explore the source of heterogeneity, and the random-effects model was selected for the combined analysis. The fixed-effects model was chosen for the combined analysis if there was no heterogeneity. Publication bias was assessed using Egger's test and funnel plot.

RESULTS

Risk factors for neonatal hyperbilirubinemia were exclusive breastfeeding (BF: OR =1.74, 95% CI: 1.42, 2.12, Z=5.43, P<0.00001); glucose-6-phosphate dehydrogenase deficiency (G6PD: OR =1.62, 95% CI: 1.44, 1.81, Z=8.39, P<0.00001); maternal-fetal ABO blood group incompatibility (OR =1.64, 95% CI: 1.42, 1.89, Z=6.75, P<0.00001); and preterm birth (PTB: OR =1.31, 95% CI: 1.17, 1.47, Z=4.60, P<0.00001); there was no heterogeneity or publication bias among the studies (BF: χ²=5.34, P=0.25, I²=25%; G6PD: χ²=4.40, P=0.49, I²=0%; ABO: χ²=1.91, P=0.75, I²=0%; PTB: χ²=0.81, P=0.67, I²=0%).

CONCLUSIONS

Exclusive breastfeeding, G6PD deficiency, ABO incompatibility and premature birth were confirmed as risk factors for neonatal hyperbilirubinemia. Pregnant women with risk factors should be monitored more closely and clinical intervention should be given in a timely manner.

Is Neonatal Hyperbilirubinemia Exposure Associated with a Risk of Autism Spectrum Disorder? A Nationwide Cohort Study

OBJECTIVE

This study aimed to determine whether neonatal hyperbilirubinemia is associated with a risk of autism spectrum disorder (ASD) using a large population-based cohort.

STUDY DESIGN

This retrospective cohort study used data from the children's database (2000-2012) of the National Health Insurance Research Database (1996-2012) in Taiwan. We included neonates who were born between 2000 and 2004 and aged <1 month diagnosed with and without hyperbilirubinemia. The primary outcome was physician-diagnosed ASD. At the end of 2012, multivariate Cox's regression analysis was used to estimate hazard ratios (HRs).

RESULTS

A total of 67,017 neonates were included. The neonates with hyperbilirubinemia were associated with 1.28-fold increased risk of ASD (HR = 1.28, 95% confidence interval [CI]: 1.05-1.57) compared with those without hyperbilirubinemia. In subanalysis to determine how phototherapy and exchange transfusion treatment for hyperbilirubinemia were associated with ASD showed no association between treatment and ASD, suggesting the lack of a dose-response effect of hyperbilirubinemia on the risk of ASD. Boys had a nearly six-fold higher risk of ASD than girls (HR = 5.89, 95% CI: 4.41-7.86). Additionally, neonates born with preterm birth and low birth weight were associated with a risk of ASD (HR = 1.46, 95% CI: 1.00-2.13).

CONCLUSION

We did not observe a dose-response effect of hyperbilirubinemia on ASD, but neonatal hyperbilirubinemia may be an independent risk factor for ASD if there is a residual confounding by other perinatal complications. Therefore, this study does not support a causal link between neonatal hyperbilirubinemia exposure and the risk of ASD.

Hemolysis due to Alpha-Hemolytic Enterococcus Urinary Infection: A Rare Cause of Early and Severe Unconjugated Hyperbilirubinemia in a Neonate

The reason for reporting this case is to remind that some microorganisms may cause hemolysis leading to early and severe hyperbilirubinemia by secreting hemolysin in cases; where bilirubin levels cannot be successfully decreased despite effective phototherapy, intravenous immunoglobulin, and even exchange transfusion, or in cases of increased rebound bilirubin (although urinary tract infection is associated with increased conjugated bilirubin fraction and prolonged jaundice). The most common causes of hemolysis are ABO/Rh incompatibility and enzyme deficiencies such as glucose-6-phosphate dehydrogenase (G6PDH), pyruvate kinase (PK), and galactose-1-phosphate uridyltransferase (GALT). Our patient was a male infant, weighing 3,160 g, at 38 + 4 gestational week; he was referred to our unit with total bilirubin level of 14.7 mg/dL recorded at the postnatal 20th hour and was initiated treatment with intensive phototherapy and prepared for exchange transfusion. The G6PD, PK, and GALT enzyme levels studied at the postnatal 96th hour and reducing substances in urine were detected to be normal/negative, whereas complete urinalysis revealed pyuria (7 leukocytes per each high power field). α-hemolysis-producing 105 colony-forming unit/mL Enterobacter cloacae grew on blood agar in the urine culture. As reported in our case, hemolysin-secreting α and β-hemolytic bacteria can lead to severe and early hemolysis and unconjugated hyperbilirubinemia, as in blood type incompatibility and enzyme deficiencies.

Incidence and molecular characterization of Glucose-6-Phosphate Dehydrogenase deficiency among neonates for newborn screening in Chaozhou, China

INTRODUCTION

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is highly prevalent in southern China. The aim of this study is to assess the extent of this disease in Chinese neonates and determine its molecular characteristics using a novel molecular screening method.

METHODS

A total of 2500 neonates were routinely screened for G6PD deficiency using a modified fluorescent spot test (FST). PCR-high-resolution melting (HRM) analysis was then used for the molecular assay.

RESULTS

The overall incidence of G6PD deficiency was 2.68% in our study cohort. Frequency in male population was 3.22% (44 neonates of 1365 male neonates), and in female population was 2.03% (23 neonates of 1135 female neonates). Of the 67 newborns suspected to be G6PD deficient based on FST (44 males, 23 females), 58 of 67 (87%) were detected with gene alterations. Seven kinds of mutations [c.95A>G, c.392G>T, c.493A>G, c.871G>A, c.1360C>T, c.1376G>T, and c.1388G>A] were identified by HRM analysis.

CONCLUSION

Routine newborn screening in Chaozhou, China with a relatively high prevalence of G6PD deficiency is justified and meets the World Health Organization recommendation. The usage of molecular diagnosis can favor the detection of heterozygotes which can be a supplement to regular newborn screening and useful for premarital and prenatal diagnosis for G6PD deficiency.

Predictors of acute bilirubin encephalopathy among Nigerian term babies with moderate-to-severe hyperbilirubinaemia

OBJECTIVE

To determine predictors of acute bilirubin encephalopathy (ABE) among term infants presenting with moderate-to-severe hyperbilirubinaemia.

METHODS

Babies with total serum bilirubin >15 mg/dl at the point of admission were studied in a Nigerian tertiary health facility using bivariate and multivariate analysis.

RESULTS

Out of 152 babies, 75 (49.3%) had ABE: 73 had ABE at presentation while two developed ABE after admission. Bivariate analysis showed that body weight <2.5 kg, outside delivery, low maternal education, low socio-economic status, severe anaemia, glucose-6-phosphate dehydrogenase deficiency and metabolic acidosis were significantly associated with ABE. Multivariate analysis also showed that only outside delivery, weight <2.5 kg, presence of severe anaemia and acidosis were the predictors of ABE in this cohort of term babies.

CONCLUSION

The identified predictors of ABE are modifiable and can be used to draw up screening tools for term babies at risk of ABE especially in the developing world.

Infants with severe neonatal jaundice in Lagos, Nigeria: incidence, correlates and hearing screening outcomes

OBJECTIVES

To establish the incidence, correlates and hearing screening outcomes of infants with severe neonatal jaundice in Nigeria.

METHODS

Community-based study in which all infants attending Bacille Calmette-Guérin immunisation clinics in inner-city Lagos were enrolled into a universal hearing screening programme during which correlates of severe neonatal jaundice (requiring phototherapy and/or exchange blood transfusion) were explored with multivariable logistic regression.

RESULTS

Of the 5262 infants enrolled, only 48.7% were born in hospitals although almost all mothers (97.9%) attended antenatal clinics. 6.7% had a history of neonatal jaundice of whom 5.5% (95% CI:4.9-6.2) received phototherapy and 1.9% (95% CI:1.5-2.3) had an exchange blood transfusion. Factors independently associated with severe neonatal jaundice were maternal religion, occupation, use of herbal preparations during pregnancy, infant's gender, weight at screening, multiple gestation and place of birth. All but two infants with severe neonatal jaundice were exclusively breast-fed. Of those who failed the hearing tests, 17.3% were treated with phototherapy and 11.3% had an exchange blood transfusion. At least 8.9% of infants requiring phototherapy and 17.3% of those requiring exchange blood transfusion were at risk of sensorineural hearing loss.

CONCLUSIONS

Severe neonatal jaundice is a significant condition associated with modifiable risk factors in this population. Policy initiatives for prevention, early detection followed by appropriate and timely intervention are urgently needed to reduce the disease burden.

Neurodevelopmental outcome of severe neonatal hemolytic hyperbilirubinemia

We recruited 128 neonates with hyperbilirubinemia over a 5-year period (1995-2000) to study the short- and long-term effects of hemolytic hyperbilirubinemia on the auditory brainstem pathway and neurodevelopmental status. These children were divided into two groups: (1) a hemolytic group (n = 29; ABO incompatibility [n = 19], Rh incompatibility [n = 1], glucose-6-phosphate dehydrogenase deficiency [n = 8] and both ABO incompatibility and glucose-6-phosphate dehydrogenase deficiency [n = 1]) and (2) a nonhemolytic group (n = 99). All received phototherapy. Exchange transfusions were performed for four (13.8%) in the hemolytic group and three (3%) in the nonhemolytic group. The brainstem auditory evoked potential was recorded at a mean age of 3.2 months in the hemolytic group and 3.1 months in the nonhemolytic group. Serial brainstem auditory evoked potential assessments were performed until 2 years of age (3 in the hemolytic group and 18 in the nonhemolytic group). All had regular physical, neurologic, visual, and auditory evaluation until 3 years of age. The rate of exchange transfusion was significantly higher in the hemolytic group than in the nonhemolytic group (P < .05). Brainstem auditory evoked potential abnormalities at the initial assessment occurred in three (10.4%) in the hemolytic group (all related to ABO incompatibility) and nine (9.1%) in the nonhemolytic group. At 2 years, the brainstem auditory evoked potential returned to normal except in three cases with a slightly increased hearing threshold (one [3.5%] in the hemolytic group at 60 dB nHL and two [2%] in the nonhemolytic group at 50 dB nHL]). There were no significant differences in the rate of brainstem auditory evoked potential abnormalities at the initial or subsequent assessments between both groups. All except five cases had a normal neurodevelopmental outcome at 3 years (three [two with ABO incompatibility and one with glucose-6-phosphate dehydrogenase deficiency] in the hemolytic group [10.4%] and two [2%] in the nonhemolytic group). All had mild motor delay and hypotonia, which returned to normal at 3 years. The rate of abnormal neurodevelopmental outcome was higher in the hemolytic group than in the nonhemolytic group, although with no significant difference between both groups (P = .08). All five cases in both groups with abnormal neurodevelopment had a normal brainstem auditory evoked potential at the initial assessment. There was no relationship between the abnormal initial brainstem auditory evoked potential and the final neurodevelopmental outcome. The toxic effect of hyperbilirubinemia on the auditory brainstem pathway and neurodevelopmental status in our cohort was transient. The prognosis of neonatal hemolytic hyperbilirubinemia in our Chinese cohort is excellent, possibly owing to an aggressive early-intervention approach.

Genetic factors related to unconjugated hyperbilirubinemia amongst adults

Some variations in the UDP-glucuronosyltransferase 1A1 (UGT1A1) gene are involved in the development of unconjugated hyperbilirubinemia. We hypothesize that other genetic factors may also be associated with this disease. A total of 227 adults with normal routine haematology and liver function (apart from bilirubin testing for which they revealed bilirubin > or = 25.7 micromol/l and unconjugated bilirubin/total bilirubin > or = 80%), and 235 sex- and age-matched controls, were recruited. All subjects were analysed for UGT1A1, glucose-6-phosphate dehydrogenase (G6PD) and organic anion transporter polypeptide 2 (OATP2) genotypes using polymerase chain reaction-restriction fragment length polymorphism. The results indicated that G6PD deficiency, variant UGT1A1 gene and variant OATP2 gene were risk factors for hyperbilirubinemia. The odds ratios (OR) (with 95% confidence interval) were 220.83 (34.68-1406.30), 73.61 (17.01-318.63), 45.15 (11.19-182.22), 15.46 (4.35-54.99) and 6.51 (1.83-23.09), respectively, for individuals featuring the common UGT1A1/OATP2 haplotypes homozygous/heterozygous, compound heterozygous/heterozygous, compound heterozygous/wild-type, heterozygous/heterozygous and heterozygous/wild-type variations amongst subjects with normal G6PD activity. Amongst the subjects with G6PD deficiency, the OR was 159.00 (24.57-1028.94) for individuals carrying variations in both UGT1A1 and OATP2 genes. The UGT1A1/OATP2 haplotypes homozygous/wild-type, homozygous/compound heterozygous and homozygous/homozygous for G6PD normal and variant/wild-type for G6PD deficient individuals were only observed in the case group, and not in the control group. Amongst hyperbilirubinemic adults, bilirubin values tended to parallel variation status of their haplotypes. Adults featuring certain haplotypes in UGT1A1, OATP2 and G6PD genes face a high risk of developing unconjugated hyperbilirubinemia.

Molecular genetics of unconjugated hyperbilirubinemia in Taiwanese

In bilirubin metabolism, increased destruction of erythrocytes, defect in the function of organic anion transporter polypeptide 2 (OATP2) or UDP-glucuronosyltransferase 1A1 (UGT1A1) may result in unconjugated hyperbilirubinemia. Although glucose-6-phosphate dehydrogenase (G6PD) deficiency is known to be associated with the development of neonatal hyperbilirubinemia, it was observed that in neonates severe hyperbilirubinemia caused by G6PD deficiency, without associated polymorphisms in the UGT1A1 or the OATP2 gene, was preventable. Variations at the nucleotide (nt) 388 of OATP2 gene and nt-211 of UGT1A1 gene, were found to be a risk factor for severe hyperbilirubinemia amongst Taiwanese neonates, respectively. G6PD deficiency, variations at nts 388 and 521 of OATP2 gene, and variations at nt-211 and in the promoter area of UGT1A1 gene were reported to be the risk factors for the occurrence of mild hyperbilirubinemia amongst Taiwanese adults. The status of the haplotypes of G6PD, OATP2, and UGT1A1 genes affected the odds ratio and the bilirubin levels in the hyperbilirubinemic subjects. Moreover, carriage of the variant-211 UGT1A1 allele, as well as UGT1A7*3 allele, was demonstrated to represent a risk factor for the development of, and a determinant for, metastases associated with Taiwanese colorectal-cancer patients. Further investigation is warranted to evaluate this phenomenon.

Risk factors for severe hyperbilirubinemia in neonates

The incidence of severe neonatal hyperbilirubinemia is higher in Asians than in whites. A case-control study was designed to investigate the effects of eight known risk factors [breast feeding, ABO incompatibility, premature birth, infection, cephalohematoma, asphyxia, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and variant UDP-glucuronosyltransferase 1A1 (UGT1A1) gene] and a suspicious analog [organic anion transporter 2 (OATP 2) gene] on severe hyperbilirubinemia in Taiwanese neonates. The 72 study subjects and 100 hospital control subjects consisted of neonates with peak serum bilirubin levels > or =342 microM and <256.5 microM, respectively. The PCR-restriction fragment length polymorphism method was applied to detect the UGT1A1, OATP 2, and G6PD genes. The results of multivariate logistic regressions, adjusted for covariates, revealed odds ratios (ORs) of 4.64 [95% confidence interval (CI): 2.25-9.57; p < 0.001], 3.36 (95% CI: 1.54-7.35; p=0.002), and 3.02 (95% CI: 1.30-6.99; p=0.010) for neonates who were fed with breast milk, and carry the variant UGT1A1 gene at nucleotide 211 and the variant OATP 2 gene at nucleotide 388, respectively. The ORs, adjusted for covariates, for the other six risk factors were not statistically significant. The ORs in neonates who had one, two, and three significant risk factors were 8.46 (95% CI: 2.75-34.48; p < 0.001), 22.0 (95% CI: 5.50-88.0; p < 0.001), and 88.0 (95% CI: 12.50-642.50; p < 0.001), respectively. In conclusion, neonates who carry the 211 and 388 variants in the UGT1A1 and OATP 2 genes, respectively, as well as feed with breast milk are at high risk to develop severe hyperbilirubinemia.

Hyperbilirubinemia in healthy neonates with glucose-6-phosphate dehydrogenase deficiency

A cohort study was carried out to assess the association between glucose-6-phosphate dehydrogenase (G6PD) deficiency, diagnosed by quantitative enzyme assay, and neonatal hyperbilirubinemia, defined as serum total bilirubin >/=15 mg/dl, in the well-baby nursery of Chang Gung Children's Hospital. Among 42,110 inborn infants, 757 male (3.54%) and 326 female (1.57%) newborns were G6PD-deficient. Compared to the occurrence of hyperbilirubinemia in G6PD-normal newborns (1.41% in male, 1.44% in female) in the well-baby nursery, a significantly higher incidence was observed in both G6PD-deficient male (11.36%) and female (7.06%) newborns. Further analyses demonstrated that the enzyme activity of G6PD in G6PD-deficient male newborns with hyperbilirubinemia (1.56+/-1.37 U/g Hb) were significantly lower than the subjects without hyperbilirubinemia (2.01+/-1.7 U/g Hb). No significant difference was observed in G6PD-deficient female newborns with hyperbilirubinemia (6.91+/-2.76 U/g Hb) compared to those without hyperbilirubinemia (7.81+/-2.84 U/g Hb). These data suggest that the G6PD-deficient neonates are at increased risk for hyperbilirubinemia even in the nursery free from agents that can potentially cause hemolysis to G6PD-deficient red cells. The lower G6PD enzyme activity was associated with the neonatal hyperbilirubinemia in G6PD-deficient male neonates.

Glucose-6-phosphate dehydrogenase deficiency, the UDP-glucuronosyl transferase 1A1 gene, and neonatal hyperbilirubinemia

BACKGROUND & AIMS

Coinheritance of the A(TA)7TAA promoter variant in the uridine 5'-diphosphate-glucuronosyl transferase 1A1 (UGT1A1) gene and glucose-6-phosphate dehydrogenase (G6PD) deficiency is crucial to hyperbilirubinemia in white male neonates. A variation rate of 29.3% was determined within the coding region of the UGT1A1 gene in Taiwanese subjects, suggesting the hypothesis that this variation may influence incidence of hyperbilirubinemia in male neonates with G6PD deficiency.

METHODS

The full sequence of the UGT1A1 gene was identified for 212 G6PD-deficient and 232 control male neonates by using polymerase chain reaction (PCR).

RESULTS

Both study and control groups were divided into 5 subgroups according to their UGT1A1 genotypes. Most subjects carried G to A variation at nucleotide 211 for both genotypes of heterozygous variation within coding region and homozygous variation. No significant differences were noted for the frequencies of the 5 UGT1A1 genotypes, gestation age, and birth weight comparing the G6PD-deficient and control groups. The incidence of hyperbilirubinemia, however, was significantly higher for the study group than for the controls. This difference was noted only for the subgroup bearing the homozygous variant of the UGT1A1 gene. In the subgroup of homozygous variation, the serum bilirubin value was significantly higher for G6PD-deficient neonates than for controls. All 11 G6PD-deficient neonates with the homozygous 211 G to A variation suffered from hyperbilirubinemia.

CONCLUSIONS

The results indicate that carriage of the homozygous 211 G to A variation within the coding region in the UGT1A1 gene is an additive risk factor for neonatal hyperbilirubinemia in G6PD-deficient Taiwanese male neonates.

Differentiation of hair growth cycle from scalp hair roots for the diagnosis of glucose-6-phosphate dehydrogenase deficiency in neonates

Hair analysis can be used as a screening tool in the diagnosis of genetic diseases. The scalp hair roots of 67 normal neonates and 39 neonates with glucose-6-phosphate dehydrogenase (G6PD) deficiency were analysed using Fourier transform infrared (FT-IR) microspectroscopy to differentiate the stages of the hair growth cycle and to diagnose the genetic disorder on the basis of spectral differences. We have demonstrated that FT-IR microspectroscopy is a rapid and effective noninvasive diagnostic method to differentiate scalp hair roots of normal neonates into the anagen, catagen or telogen phases of the hair growth cycle, using IR spectral differences within the 3000-2800 cm(-1) region and the IR peak area ratio of 2854 cm(-1)/2873 cm(-1) or 1084 cm(-1)/amide II band (p<0.001). Moreover, G6PD-deficient neonates could be accurately diagnosed from telogen phase hair roots owing to significant differences in IR peak area ratios of 2854 cm(-1)/2873(-1) or 1084 cm(-1)/amide II band compared to normal values in healthy neonates. The result suggests that the application of FT-IR microspectroscopy may be capable not only of differentiating the hair growth cycle into anagen, categen or telogen phases but also of detecting G6PD deficiency. Hair root analysis promises to be a useful complement to serum and urine analysis in the diagnosis of genetic diseases.

Neonatal hyperbilirubinemia in glucose-6-phosphate dehydrogenase-deficient heterozygotes

OBJECTIVES

We assessed the incidence of hyperbilirubinemia, defined as serum total bilirubin >/=15 mg/dL (256 micromol/L), in a cohort of Sephardic Jewish female neonates at risk for glucose-6-phosphate dehydrogenase (G-6-PD) deficiency with especial emphasis on the heterozygotes. We studied the roles of hemolysis by blood carboxyhemoglobin (COHb) determinations and of the variant promoter of the gene for the bilirubin-conjugating enzyme uridine 5'-diphosphate glucuronosyltransferase 1 (UGT1A1) seen in Gilbert's syndrome in the pathogenesis of the hyperbilirubinemia.

METHODS

Consecutively born, healthy, term, female neonates were screened for G-6-PD deficiency and observed clinically with serum bilirubin evaluations as indicated for hyperbilirubinemia. On day 3, blood was sampled for COHb, total hemoglobin (tHb), and a mandatory serum bilirubin determination. COHb, determined by gas chromatography, was expressed as percentage of tHb and corrected for inspired carbon monoxide (COHbc). DNA was analyzed for the G-6-PD Mediterranean563T mutation and for the variant UGT1A1 gene.

RESULTS

The cohort included 54 G-6-PD-deficient heterozygotes, 19 deficient homozygotes, and 112 normal homozygotes. More heterozygotes (12/54, 22%; relative risk: 2.26; 95% CI: 1.07-4.80) and deficient homozygotes (5/19, 26.3%; relative risk: 2.68; 95% CI: 1.05-6.90) developed hyperbilirubinemia, than did normal homozygotes (11/112, 9.8%). Third-day serum bilirubin values that were obtained from 144 neonates were significantly higher in both heterozygotes (11.2 +/- 3. 7 mg/dL [192 +/- 64 micromol/L]) and G-6-PD-deficient homozygotes (12.0 +/- 3.0 mg/dL [206 +/- 52 micromol/L]) than in the G-6-PD normal homozygotes (9.4 +/- 3.4 mg/dL [160 +/- 58 micromol/L). In contrast, COHbc values were higher only in G-6-PD-deficient homozygotes (0.74% +/- 0.14%) and not in heterozygotes (0.69% +/- 0. 19%, not statistically significant), compared with control values (0. 63% +/- 0.19%). High COHbc values were not a prerequisite for the development of hyperbilirubinemia in any of the G-6-PD genotypes. A greater incidence of hyperbilirubinemia was found among the G-6-PD-deficient heterozygotes, who also had the variant UGT1A1 gene, in both heterozygous (6/20, 30%) and homozygous (4/8, 50%) forms, than was found in their counterparts with the normal UGT1A1 gene (2/26, 7.7%). This effect was not seen in the G-6-PD normal homozygote group. A color reduction screening test for G-6-PD deficiency identified only 20.4% (11/54) of the heterozygotes.

CONCLUSIONS

We showed that G-6-PD-deficient heterozygotes, categorically defined by DNA analysis, are at increased risk for neonatal hyperbilirubinemia. The screening test that was used was unable to detect most heterozygotes. Increased bilirubin production was not crucial to the development of hyperbilirubinemia, but presence of the variant UGT1A1 gene did confer increased risk.

Content of reduced glutathione and consequences in recipients of glucose-6-phosphate dehydrogenase deficient red blood cells

The red blood cell glucose-6-phosphate dehydrogenase (G6PD) activity of every donor was examined with automatic enzyme-coupled method. The technique of molecular biology was applied to determine the DNA mutations for the 97 donors with undetectable G6PD activity. The concentration of reduced glutathione (GSH) in the stored RBC of the 97 G6PD-deficient donors and 124 normal donors was determined with the technique of high performance liquid chromatography. Routine blood counts, bilirubin and haptoglobin levels were used to evaluate posttransfusional hemolysis for the 48 adult patients transfused with 1 U G6PD deficient and 1 U normal RBC. Most (88, 90.7%) of the 97 donors were confirmed to be G6PD deficient at the DNA level. At each age interval of storage, the GSH concentration of G6PD-deficient RBC was significantly different from that of normal RBC. The total average value of GSH (pmol/gHb) was 2.52 +/- 0.95 (mean +/- 1 standard deviation) vs. 3.74 +/- 1.43 (P < 0.001). Hemoglobin, hematocrit, bilirubin, and haptoglobin levels in the patients receiving G6PD-deficient RBC were not statistically different from those in the recipients of normal RBC; even though the age of stored blood was 26-35 days. Within the same group of patients, the results of bilirubin and haptoglobin were not significantly changed before and after transfusion. The results of this study show that the GSH concentration in the stored blood of G6PD deficient donors was 67% of that in the normal donors. However, hemolysis does not occur in adult patients transfused with 1 U G6PD-deficient RBC. It seems unnecessary to screen G6PD activity for donors of adult recipients in Taiwan.

Neonatal jaundice and molecular mutations in glucose-6-phosphate dehydrogenase deficient newborn infants

Molecular mutations of the glucose-6-phosphate dehydrogenase (G6PD) gene and clinical manifestations of neonatal jaundice in 112 male and 50 female Chinese neonates with G6PD deficiency were studied. In the 112 males, the nucleotide (nt) 1376 (G-->T) mutation was the dominant type (50.0%), followed by nt 1388 (G-->A) (16.1%), nt 493 (A-->G) (8.0%), nt 1024 (C-->T) (6.2%), nt 95 (A-->G) (5.4%), nt 392 (G-->T) (1.8%), nt 487 (G-->A) (1.8%), nt 871 (G-->A) (0.9%), and nt 1360 (C-->T) (0.9%). The nt 871 variant has not been reported in Taiwan before. The occurrence rates for nt 1376, nt 1388, nt 493, nt 95, and nt 1024 mutations in the 50 females were 44.0%, 18.0%, 12.0%, 6.0%, and 6.0%, respectively. The type of G6PD mutation in 10 male and 7 female neonates has not been identified yet. Although G6PD deficient neonates had higher frequency of phototherapy than G6PD normal neonates in both sexes, a significant difference in the prevalence of hyperbilirubinemia (peak bilirubin > or = 15.0 mg/dl) between G6PD deficient and normal neonates was found only in males. Further analysis showed that duration of phototherapy was longer in G6PD deficient male neonates than in the control group, while the outcome of phototherapy was better in subjects with non-nt 1376 mutations than subjects with the nt 1376 mutation. Most (78.3%) of the 23 G6PD deficient neonates who subsequently suffered from neonatal hyperbilirubinemia carried the nt 1376 mutation. The results of this study indicate that the nucleotide substitution at 1376 is the most common and important mutation for G6PD deficiency in Chinese neonates in Taiwan.