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

Newborn screening for G6PD deficiency in HeFei, FuYang and AnQing, China: Prevalence, cut-off value, variant spectrum

Background

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive Mendelian genetic disorder characterized by neonatal jaundice and hemolytic anemia, affecting more than 400 million people worldwide. The purpose of this research was to investigate prevalence rates of G6PD deficiency and to evaluate and establish specific cut-off values in early prediction of G6PD deficiency by regions (HeFei, FuYang, AnQing) on different seasons, as well as to investigate the frequencies of G6PD gene mutations among three regions mentioned above.

Methods

A total of 31,482 neonates (21,402, 7680, and 2340 for HeFei, FuYang, and AnQing cities, respectively) were recruited. Positive subjects were recalled to attend genetic tests for diagnosis. G6PD activity on the Genetic screening processor (GSP analyzer, 2021-0010) was measured following the manufactureržs protocol. The cut-off value was first set to 35 U/dL. The receiver operating characteristics (ROC) curve was employed to assess and compare the efficiency in predicting G6PD deficiency among HeFei, FuYang, and AnQing cities in different seasons.

Molecular epidemiological investigation of G6PD deficiency in Yangjiang region, western Guangdong province

Objectives: The prevalence of G6PD deficiency has not been reported in Yangjiang, a western city in Guangdong province. This study aims to investigate the molecular characteristics of G6PD deficiency in this region. Methods: Blood samples were collected from adults at a local hospital to screen for G6PD deficiency. The deficient samples were subjected to further analysis using PCR and reverse dot blot to determine the specific G6PD variants. Results: Among the 3314 male subjects, 250 cases of G6PD deficiency were found using the G6PD enzyme quantitative assay, resulting in a prevalence of 7.54% (250/3314) in the Yangjiang region. The prevalence of G6PD deficiency in females was 3.42% (176/5145). Out of the 268 cases of G6PD deficiency tested for G6PD mutations, reverse dot blot identified 20 different G6PD variants. The most common G6PD variant was c.1388G>A (81/268), followed by c.1376G>T (48/268), c.95A>G (32/268), c.1024C>T (9/268), c.392G>T (7/268), and c.871G>A/c.1311C>T (6/268). It was observed that c.871G>A was always linked to the polymorphism of c.1311C>T in this population. Conclusion: This investigation into G6PD deficiency in this area is expected to significantly improve our understanding of the prevalence and molecular characterization of this condition.

Molecular heterogeneity of glucose-6-phosphate dehydrogenase deficiency in neonates in Wuhan: Description of four novel variants

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common X-linked enzymopathies caused by G6PD gene variant. The aim of this study was to investigate the molecular epidemiological characteristic of the G6PD deficiency among newborn screening population in Wuhan region. A total of 430,806 healthy neonates in Wuhan area of China were screened for G6PD deficiency from November 2016 to December 2021. The positive samples were further detected with gene analysis. Among the 957 neonates with abnormal G6PD enzyme activity, the prevalence of G6PD deficiency in Wuhan was calculated as 0.22%. 38 genotypes were found and the top 5 frequencies of G6PD gene variants were c.1388G > A, c.1376G > T, c.95A > G, c.1024C > T and c.871G > A. Seven rare single variants (c.25C > T, c.152C > T, c.406C > T, c.497G > A, c.679C > T, c.854G > A and c.1057C > T) and two rare multiple variants (IVS-5 637/638T del/c.1311C > T/1365-13T > C and c.406C > T/c.1311C > T/1365-13T > C) were discovered in this study. In addition, four novel variants (c.49C > T, c.691G > A, c.857A > T and c.982G > A) were detected out in our cohort, which have never been reported before. The result indicated that a rich diversity of G6PD genetic variants in Wuhan region, also had its own regional characteristic. Our data provided the basic knowledge for future prevention and research of G6PD deficiency and the findings will be useful for genetic counseling and prenatal diagnosis of G6PD deficiency in the Wuhan region.

Simultaneous detection of G6PD mutations using SNPscan in a multiethnic minority area of Southwestern China

Objectives: Baise, a multiethnic inhabited area of southwestern China, is a historical malaria-endemic area with a high prevalence of G6PD deficiency. However, few studies of G6PD deficiency have been conducted in this region. Therefore, we performed a genetic analysis of G6PD deficiency in the Baise population from January 2020 to June 2021. Methods: A SNPscan assay was developed to simultaneously detect 33 common Chinese G6PD mutations. 30 G6PD-deficient samples were used for the method's validation. Then, a total of 709 suspected G6PD-deficient samples collated from the Baise population were evaluated for G6PD status, type of mutation and effect of mutations. Results: The SNPscan test had a sensitivity of 100% [95% confidence interval (CI): 94.87%-100%] and a specificity of 100% (95% CI: 87.66%-100%) for identifying G6PD mutations. A total of fifteen mutations were identified from 76.72% (544/709) of the samples. The most common mutation was discovered to be G6PD Kaiping (24.12%), followed by G6PD Canton (17.91%), and G6PD Gaohe (11.28%). We compared the G6PD mutation spectrum among Zhuang, Han and other Southeast Asian populations, and the Zhuang population's mutation distribution was quite similar to that in the Han population. Conclusion: This study provided a detailed G6PD mutation spectrum in Baise of southwestern China and will be valuable for the diagnosis and research of G6PD deficiency in this area. Furthermore, the SNPscan assay could be used to quickly diagnose these G6PD mutations accurately.

Co-inheritance of G6PD deficiency and 211 G to a variation of UGT1A1 in neonates with hyperbilirubinemia in eastern Guangdong

Background

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, which may manifest as neonatal hyperbilirubinemia, is the most prevalent erythrocytic enzyme-related disease in the world.

Objective

To investigate the association between neonatal hyperbilirubinemia and co-inheritance of G6PD deficiency and 211 G to A variation of UGT1A1 in Chaozhou city of eastern Guangdong province, the effects of G6PD deficiency and UGT1A1 gene variant on the bilirubin level were determined in neonates with hyperbilirubinemia.

Method

The activity of G6PD was assayed by an auto-bioanalyzer. PCR and flow-through hybridization were used to detect 14 common G6PD mutations in G6PD deficient neonates. 211 G to A variation of UGT1A1 was determined by PCR and sequencing. The data of neonatal bilirubin was collected and analyzed retrospectively.

Results

Seventy four cases of the 882 hyperbilirubinemia neonates were G6PD deficiency (8.39%) while 12 cases of the 585 non-hyperbilirubinemia neonates (control group) were G6PD deficiency (2.05%). The rate of G6PD deficiency in the hyperbilirubinemia group was higher than that of the control group. Moreover, the peak bilirubinin of the G6PD-deficient group of hyperbilirubinemia neonates was 334.43 ± 79.27 μmol/L, higher than that of the normal G6PD group of hyperbilirubinemia neonates (300.30 ± 68.62 μmol/L). The most common genotypes of G6PD deficiency were c.1376G > T and c.1388G > A, and the peak bilirubin of neonates with these two variants were 312.60 ± 71.81 μmol/L and 367.88 ± 75.79 μmol/L, respectively. The bilirubin level of c.1388G > A was significantly higher than that of c.1376G > T. Among the 74 hyperbilirubinemia neonates with G6PD deficiency, 6 cases were 211 G to A homozygous mutation (bilirubin levels 369.55 ± 84.51 μmol/L), 27 cases were 211 G to A heterozygous mutation (bilirubin levels 341.50 ± 63.21 μmol/L), and 41 cases were wild genotypes (bilirubin levels 324.63 ± 57.52 μmol/L).

Conclusion

The rate of G6PD deficiency in hyperbilirubinemia neonates was significantly higher than that of the non-hyperbilirubinemia neonates in Chaozhou. For the hyperbilirubinemia group, neonates with G6PD deficiency had a higher bilirubin level compared to those with normal G6PD. For hyperbilirubinemia neonates with G6PD deficiency, there was a declining trend of bilirubin levels among 211 G to A homozygous mutation, heterozygous mutation, and wild genotype, but there was no significance statistically among the three groups.

Newborn Screening for G6PD Deficiency in Xiamen, China: Prevalence, Variant Spectrum, and Genotype-Phenotype Correlations

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common inherited enzymatic defect. The purpose of this study was to evaluate the profile of G6PD deficiency and investigate the factors associated with the accuracy of newborn screening (NBS) in Xiamen, China.

Methods: A total of 99,546 newborns were screened by modified fluorescent spot test at the Women and Children’s Hospital, Xiamen University. High-risk neonates were recalled for diagnosis by either a measurement of G6PD activity or genetic testing for the presence of pathogenic G6PD variants using a quantitative G6PD enzymatic assay or the MeltPro® G6PD assay, respectively.

Results: In the first-tier screening, 1,256 newborns were categorized as high risk. Of these, 1,051 were diagnosed with G6PD deficiency, indicating a prevalence of 1.39% in Xiamen, China. Among the 1,013 neonates who underwent genotyping, 851 carried hemizygous, heterozygous, homozygous, or compound heterozygous variants, for a positive predictive value (PPV) of 84.01%. In total, 12 variants and 32 genotypes were identified, and the six most common variants were c.1376G>T, c.1388G>A, c.95A>G, c.1024C>T, c.871G>A, and c.392G>T, which accounted for approximately 94% of the identified alleles. Different variants showed characteristic enzymatic activities, although high phenotypic heterogeneity was observed for each variant. The use of cold-chain transportation significantly improved the PPV of NBS.

Conclusions: We determined the profile of G6PD deficiency in Xiamen, including the prevalence, variant spectrum, and genotype-phenotype correlations and confirmed that maintaining a low temperature during sample transport is essential to ensure the high screening accuracy of NBS. Our data provides epidemiological, genotypic, phenotypic, and clinical practice references to standardize future interventions for G6PD deficiency.

Molecular Characterization of Glucose-6-Phosphate Dehydrogenase Deficiency in the Shenzhen Population

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is caused by one or more mutations in the G6PD gene on chromosome X. This study aimed to characterize the G6PD gene variant distribution in Shenzhen of Guangdong province.

METHODS

A total of 33,562 individuals were selected at the hospital for retrospective analysis, of which 1,213 cases with enzymatic activity-confirmed G6PD deficiency were screened for G6PD gene variants. Amplification refractory mutation system PCR was first used to screen the 6 dominant mutants in the Chinese population (c.1376G>T, c.1388G>A, c.95A>G, c.1024C>T, c.392G>T, and c.871G>A). If the 6 hotspot variants were not found, next-generation sequencing was then performed. Finally, Sanger sequencing was used to verify all the mutations.

RESULTS

The incidence of G6PD deficiency in this study was 3.54%. A total of 26 kinds of mutants were found in the coding region, except for c.-8-624T>C, which was in the noncoding region. c.1376G>T and c.1388G>A, both located in exon 12, were the top 2 mutants, accounting for 68.43% of all individuals. The 6 hotspot mutations had a cumulative proportion of 94.02%.

CONCLUSIONS

This study provided detailed characteristics of G6PD gene variants in Shenzhen, and the results would be valuable to enrich the knowledge of G6PD deficiency.

Glucose-6-phosphate dehydrogenase mutations in malaria endemic area of Thailand by multiplexed high-resolution melting curve analysis

Background

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzymopathy in humans, is prevalent in tropical and subtropical areas where malaria is endemic. Anti-malarial drugs, such as primaquine and tafenoquine, can cause haemolysis in G6PD-deficient individuals. Hence, G6PD testing is recommended before radical treatment against vivax malaria. Phenotypic assays have been widely used for screening G6PD deficiency, but in heterozygous females, the random lyonization causes difficulty in interpreting the results. Over 200 G6PD variants have been identified, which form genotypes associated with differences in the degree of G6PD deficiency and vulnerability to haemolysis. This study aimed to assess the frequency of G6PD mutations using a newly developed molecular genotyping test.

Methods

A multiplexed high-resolution melting (HRM) assay was developed to detect eight G6PD mutations, in which four mutations can be tested simultaneously. Validation of the method was performed using 70 G6PD-deficient samples. The test was then applied to screen 725 blood samples from people living along the Thai–Myanmar border. The enzyme activity of these samples was also determined using water-soluble tetrazolium salts (WST-8) assay. Then, the correlation between genotype and enzyme activity was analysed.

Results

The sensitivity of the multiplexed HRM assay for detecting G6PD mutations was 100 % [95 % confidence interval (CI): 94.87–100 %] with specificity of 100 % (95 % CI: 87.66–100 %). The overall prevalence of G6PD deficiency in the studied population as revealed by phenotypic WST-8 assay was 20.55 % (149/725). In contrast, by the multiplexed HRM assay, 27.17 % (197/725) of subjects were shown to have G6PD mutations. The mutations detected in this study included four single variants, G6PD Mahidol (187/197), G6PD Canton (4/197), G6PD Viangchan (3/197) and G6PD Chinese-5 (1/197), and two double mutations, G6PD Mahidol + Canton (1/197) and G6PD Chinese-4 + Viangchan (1/197). A broad range of G6PD enzyme activities were observed in individuals carrying G6PD Mahidol, especially in females.

Conclusions

The multiplexed HRM-based assay is sensitive and reliable for detecting G6PD mutations. This genotyping assay can facilitate the detection of heterozygotes, which could be useful as a supplementary approach for high-throughput screening of G6PD deficiency in malaria endemic areas before the administration of primaquine and tafenoquine.

Epidemiology, evolutionary origin, and malaria-induced positive selection effects of G6PD-deficient alleles in Chinese populations

BACKGROUND

Although glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common inherited disorder in the Chinese population, there is scarce evidence regarding the epidemiology, evolutionary origin, and malaria-induced positive selection effects of G6PD-deficient alleles in various Chinese ethnic populations.

METHODS

We performed a large population-based screening (n = 15,690) to examine the impact of selection on human nucleotide diversity and to infer the evolutionary history of the most common deficiency alleles in Chinese populations.

RESULTS

The frequencies of G6PD deficiency ranged from 0% to 11.6% in 12 Chinese ethnic populations. A frequency map based on geographic information showed that G6PD deficiency was highly correlated with historical malaria prevalence in China and was affected by altitude and latitude. The five most frequently occurring G6PD gene variants were NM_001042351.3:c.1376G>T, NM_001042351.3:c.1388G>A, NM_001042351.3:c.95A>G, NM_001042351.3:c.1311T>C, and NM_001042351.3:c.1024C>T, which were distributed with ethnic features. A pathogenic but rarely reported variant site (NM_001042351.3:c.448G>A) was identified in this study. Bioinformatic analysis revealed a strong and recent positive selection targeting the NM_001042351.3:c.1376G>T allele that originated in the past 3125 to 3750 years and another selection targeting the NM_001042351.3:c.1388G>A allele that originated in the past 5000 to 6000 years. Additionally, both alleles originated from a single ancestor.

CONCLUSION

These results indicate that malaria has had a major impact on the Chinese genome since the introduction of rice agriculture.

A novel G6PD deleterious variant identified in three families with severe glucose-6-phosphate dehydrogenase deficiency

BACKGROUND

Glucose-6-phosphate dehydrogenase deficiency (D-G6PD) is an X-linked recessive disorder resulted from deleterious variants in the housekeeping gene Glucose-6-phosphate 1-dehydrogenase (G6PD), causing impaired response to oxidizing agents. Screening for new variations of the gene helps with early diagnosis of D-G6PD resulting in a reduction of disease related complications and ultimately increased life expectancy of the patients.

METHODS

One thousand five hundred sixty-five infants with pathological jaundice were screened for G6PD variants by Sanger sequencing all of the 13 exons, and the junctions of exons and introns of the G6PD gene.

RESULTS

We detected G6PD variants in 439 (28.1%) of the 1565 infants with pathological jaundice. In total, 9 types of G6PD variants were identified in our cohort; and a novel G6PD missense variant c.1118 T > C, p.Phe373Ser in exon 9 of the G6PD gene was detected in three families. Infants with this novel variant showed decreased activity of G6PD, severe anemia, and pathological jaundice, consistent with Class I G6PD deleterious variants. Analysis of the resulting protein's structure revealed this novel variant affects G6PD protein stability, which could be responsible for the pathogenesis of D-G6PD in these patients.

CONCLUSIONS

High rates of G6PD variants were detected in infants with pathological jaundice, and a novel Class I G6PD deleterious variants was identified in our cohort. Our data reveal that variant analysis is helpful for the diagnosis of D-G6PD in patients, and also for the expansion of the spectrum of known G6PD variants used for carrier detection and prenatal diagnosis.

Evidence of positively selected G6PD A- allele reduces risk of Plasmodium falciparum infection in African population on Bioko Island

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) is an essential enzyme that protects red blood cells from oxidative damage. Although G6PD-deficient alleles appear to confer a protective effect of malaria, the link with clinical protection against Plasmodium infection is conflicting.

METHODS

A case-control study was conducted on Bioko Island, Equatorial Guinea and further genotyping analysis used to detect natural selection of the G6PD A- allele.

RESULTS

Our results showed G6PD A- allele could significantly reduce the risk of Plasmodium falciparum infection in male individuals (adjusted odds ratio [AOR], 0.43; 95% confidence interval [CI], 0.20-0.93; p < .05) and homozygous female individuals (AOR, 0.11; 95% CI, 0.01-0.84; p < .05). Additionally, the parasite densities were significantly different in the individuals with different G6PD A- alleles and individual levels of G6PD enzyme activity. The pattern of linkage disequilibrium and results of the long-range haplotype test revealed a strong selective signature in the region encompassing the G6PD A- allele over the past 6,250 years. The network of inferred haplotypes suggested a single origin of the G6PD A- allele in Africans.

CONCLUSION

Our findings demonstrate that glucose-6-phosphate dehydrogenase (G6PD) A- allele could reduce the risk of P. falciparum infection in the African population and indicate that malaria has a recent positive selection on G6PD A- allele.

A novel mutation of the ITGB2 gene in a Chinese Zhuang minority patient with leukocyte adhesion deficiency type 1 and glucose-6-phosphate dehydrogenase deficiency

OBJECTIVES

To explore the clinical and molecular characteristics of a Chinese Zhuang minority patient with leukocyte adhesion deficiency type-1 (LAD-1) and glucose-6-phosphate dehydrogenase deficiency (G6PDD).

METHODS

Routine clinical and physical examinations were performed, and patient data was collected and analyzed. Protein expression levels of Itgb2 and glucose-6-phosphate dehydrogenase (G6pd) proteins were assessed by flow cytometry and the glucose-6-phosphate (G6P) substrate method, respectively. Whole exome sequencing was performed to investigate genetic variations of the patient and his parents.

RESULTS

The patient had fester disease and delayed separation of the umbilical cord at birth. Staphylococcus was detected in the fluid secretion of the auditory meatus of the patient. He exhibited a recurrent cheek scab, swollen hand, and swollen gum. Hematological examination indicated dramatic elevation of leukocytes including lymphocytes, monocytes, neutrophils and eosinophils. A novel homozygous mutation was detected in the ITGB2 gene of the patient, which was determined to be a two nucleotide deletion at the site of c.1537-1538 (c.1537-1538delGT), causing a frameshift of 24 amino acids from p.513 and inducing a stop codon (p.V513Lfs*24). A base substitution mutation was identified at c.1466 (c.1466G>T) of G6PD on chromosome X of the patient, which resulted in an amino acid change from arginine to leucine at p.489 (p.R489L). The patient also showed deficient lymphocyte expression of CD18 (2.99%) and significant downregulation of the G6pd protein.

CONCLUSIONS

The patient was diagnosed with G6PDD and moderate LAD-1. The combination of LAD-1 and G6PDD in this case may have been due to the high incidence of genetic disease in this minority ethnic population. Analyzing existing LAD-1 and G6PDD cases from different populations can facilitate disease diagnosis and treatment. Particularly, reporting pathogenic mutations of LAD-1 and G6PDD will be crucial for genetic testing and prenatal diagnosis in an effort to decrease the incidence of these diseases.

The association between glucose-6-phosphate dehydrogenase deficiency and abnormal blood pressure among prepregnant reproductive-age Chinese females

The morbidity of hypertension is increasing among young adults worldwide, and glucose-6-phosphate dehydrogenase (G6PD) deficiency is a high-prevalence genetic disease. We investigated whether G6PD deficiency was associated with abnormal blood pressure (including elevated blood pressure and hypertension) among prepregnant reproductive-age females. We conducted a cross-sectional study in Shenzhen, which included 154 917 females aged 20-49 who participated in the National Free Pre-conception Check-up Projects supported by the Chinese government. After adjusting for confounding factors, the odds ratios (ORs) for the effects of G6PD deficiency on elevated blood pressure and hypertension were 1.18 (95% confidence interval (CI): 1.03-1.35) and 1.11 (95% CI: 1.00-1.23), respectively. Moreover, the association between G6PD deficiency and abnormal blood pressure was statistically significant for systolic blood pressure (SBP) but not significant for diastolic blood pressure (DBP). The multivariable-adjusted ORs for females with G6PD deficiency in the SBP 120-139 mm Hg and SBP ≥ 140 mm Hg groups were 1.10 (95% CI: 1.00-1.21) and 1.75 (95% CI: 1.25-2.42), respectively, while the multivariable-adjusted ORs for females with G6PD deficiency in the DBP 80-89 mm Hg and DBP ≥ 90 mm Hg groups were 1.09 (95% CI: 0.98-1.21) and 0.89 (95% CI: 0.66-1.19), respectively. Subgroup analyses showed similar results. The findings of this study underscored that reproductive-age females with a G6PD deficiency had a higher risk of elevated blood pressure and hypertension. Therefore, females with G6PD deficiency combined with elevated blood pressure or hypertension were high-risk populations during prepregnancy and pregnancy periods. Early intervention and collaborative management approaches should be explored to reduce the burden of these two diseases and improve maternal and child health.

Newborn screening of glucose-6-phosphate dehydrogenase deficiency in Guangxi, China: determination of optimal cutoff value to identify heterozygous female neonates

The aim of this study is to assess the disease incidence and mutation spectrum of glucose-6-phosphate dehydrogenase (G6PD) deficiency in Guangxi, China, and to determine an optimal cutoff value to identify heterozygous female neonates. A total of 130, 635 neonates were screened from the year of 2013 to 2017. Neonates suspected for G6PD deficiency were further analyzed by quantitatively enzymatic assay and G6PD mutation analysis. The overall incidence of G6PD deficiency was 7.28%. A total of 14 G6PD mutations were identified, and different mutations lead to varying levels of G6PD enzymatic activities. The best cut-off value of G6PD activity in male subjects is 2.2 U/g Hb, same as conventional setting. In female population, however, the cut-off value is found to be 2.8 U/g Hb (sensitivity: 97.5%, specificity: 87.7%, AUC: 0.964) to best discriminate between normal and heterozygotes, and 1.6 U/g Hb (sensitivity: 82.2%, specificity: 85.9%, AUC: 0.871) between heterozygotes and deficient subjects. In conclusion, we have conducted a comprehensive newborn screening of G6PD deficiency in a large cohort of population from Guangxi, China, and first established a reliable cut-off value of G6PD activity to distinguish heterozygous females from either normal or deficient subjects.

Clinical Significance of UGT1A1 Genetic Analysis in Chinese Neonates with Severe Hyperbilirubinemia

BACKGROUND

Neonatal hyperbilirubinemia is common in Asia, and the importance of genetically determined conditions has been recently recognized. The aim of this study was to assess the clinical utility of genetic testing in Chinese neonates with severe hyperbilirubinemia.

METHODS

Fifty-eight term infants with bilirubin level ≥ 20 mg/dL (342 μmol/L), and 65 controls were enrolled in the study. Variation status of UGT1A1, G6PD, and thalassemia genes in our study cohort was determined by direct sequencing or genotype assays.

RESULTS

Among these case infants, seven were confirmed with G6PD deficiency, four were heterozygous for α- or β-thalassemia, and forty-four were detected with at least one heterozygous UGT1A1 functional variant, including nine homozygous for UGT1A1 variation. As well as the predominant c.211G>A (Gly71Arg) variant, three UGT1A1 coding variants [c.1091C>T (Pro364Leu), c.1352C>T (pro451leu), and c.1456C>T (Tyr486Asp)] were observed in our case neonates. The results of multivariate logistic regressions, adjusted for covariates, revealed odds ratios for neonates who carried heterozygous, homozygous variation at nucleotide 211 of UGT1A1, and G6PD deficiency of 3.47 (1.26-9.55), 12.46 (1.09-142.7) ,and 12.87 (1.32-135.87) compared with those having the wild genotype and normal G6PD activity, respectively.

CONCLUSION

Besides G6PD-deficiency screening, UGT1A1 genetic analysis, and especially the UGT1A1*6(c.211G>A, p.Arg71Gly) polymorphism detection, may be taken into consideration for early diagnosis and treatment of severe hyperbilirubinemic newborns in southern China.

Multiple Genetic Modifiers of Bilirubin Metabolism Involvement in Significant Neonatal Hyperbilirubinemia in Patients of Chinese Descent

The potential for genetic variation to modulate neonatal hyperbilirubinemia risk is increasingly being recognized. A case-control study was designed to assess comprehensive contributions of the multiple genetic modifiers of bilirubin metabolism on significant neonatal hyperbilirubinemia in Chinese descendents. Eleven common mutations and polymorphisms across five bilirubin metabolism genes, namely those encoding UGT1A1, HMOX1, BLVRA, SLCO1B1 and SLCO1B3, were determined using the high resolution melt (HRM) assay or PCR-capillary electrophoresis analysis. A total of 129 hyperbilirubinemic infants and 108 control subjects were evaluated. Breastfeeding and the presence of the minor A allele of rs4148323 (UGTA*6) were correlated with an increased risk of hyperbilirubinemia (OR=2.17, P=0.02 for breastfeeding; OR=9.776, P=0.000 for UGTA*6 homozygote; OR=3.151, P=0.000 for UGTA*6 heterozygote); whereas, increasing gestational age and the presence of –TA₇ repeat variant of UGT1A1 decreased the risk (OR=0.721, P=0.003 for gestational age; OR=0.313, P=0.002 for heterozygote TA₆/TA₇). In addition, the SLCO1B1 and SLCO1B3 polymorphisms also contributed to an increased risk of hyperbilirubinemia. This detailed analysis revealed the impact of multiple genetic modifiers on neonatal hyperbilirubinemia. This may support the use of genetic tests for clinical risk assessment. Furthermore, the established HRM assay can serve as an effective method for large-scale investigation.

G6PD Deficiency and Hemoglobinopathies: Molecular Epidemiological Characteristics and Healthy Effects on Malaria Endemic Bioko Island, Equatorial Guinea

Background

Glucose-6-phosphate dehydrogenase (G6PD) deficiency and hemoglobinopathies were the inherited conditions found mostly in African. However, few epidemiological data of these disorders was reported in Equatorial Guinea (EQG). This study aimed to assess the prevalence and healthy effects of G6PD deficiency and hemoglobinopathies among the people on malaria endemic Bioko Island, EQG.

Materials and Methods

Blood samples from 4,144 unrelated subjects were analyzed for G6PD deficieny by fluorescence spot test (FST), high-resolution melting assay and PCR-DNA sequencing. In addition, 1,186 samples were randomly selected from the 4,144 subjects for detection of hemoglobin S (HbS), HbC, and α-thalassemia deletion by complete blood count, PCR-DNA sequencing and reverse dot blot (RDB).

Results

The prevalence of malaria and anemia was 12.6% (522/4,144) and 32.8% (389/1,186), respectively. Overall, 8.7% subjects (359/4,144) were G6PD-deficient by FST, including 9.0% (249/2,758) males and 7.9% (110/1,386) females. Among the 359 G6PD-deficient individuals molecularly studied, the G6PD A^- (G202A/A376G) were detected in 356 cases (99.2%), G6PD Betica (T968C/A376G) in 3 cases. Among the 1,186 subjects, 201 cases were HbS heterozygotes, 35 cases were HbC heterozygotes, and 2 cases were HbCS double heterozygotes; 452 cases showed heterozygous α-thalassemia 3.7 kb deletion (-α^3.7 kb deletion) and 85 homozygous - α^3.7 kb deletion. The overall allele frequencies were HbS 17.1% (203/1186); HbC, 3.1% (37/1186); and –α^3.7 kb deletion 52.4% (622/1186), respectively.

Conclusions

High G6PD deficiency in this population indicate that diagnosis and management of G6PD deficiency is necessary on Bioko Island. Obligatory newborn screening, prenatal screening and counseling for these genetic disorders, especially HbS, are needed on the island.