Prevalence of G6PD deficiency and G6PD variants amongst the southern Thai population

Screening results and mutation frequency analysis of G6PD deficiency in 1,291,274 newborns in Huizhou, China: a twenty-year experience

OBJECTIVES

This study aimed to investigate the incidence rate and spectrum of gene mutations of Glucose-6-phosphate dehydrogenase (G6PD) deficiency in the Huizhou city of southern China to provide a scientific basis for disease prevention and control in the area.

METHODS

From March 2003 to December 2022, newborn screening for G6PD enzyme activity was carried out in Huizhou city using the fluorescence quantitative method. Infants who tested positive during the initial screening were diagnosed using the nitroblue tetrazolium ratio method, while a subset of infants received further gene mutation analysis using the multicolor probe melting curve analysis method.

RESULTS

A total of 1,291,274 newborns were screened and the screening rate has increased from 20.39% to almost 100%. In the 20-year period, 57,217 (4.43%) infants testing positive during the initial screening. Out of these infants, 49,779 (87%) were recalled for confirmatory testing. G6PD deficiency was confirmed in 39,261 of the recalled infants, indicating a positive predictive value of 78.87%. The estimated incidence rate of G6PD deficiency in the region was 3.49%, which was significantly higher than the average incidence rate of 2.1% in southern China. On the other hand, seven pathogenic G6PD variants were identified in the analysis of the 99 diagnosed infants with the most common being c.1388 G > A (48.5%), followed by c.95 A > G (19.2%), c.1376 G > T (15.2%), c.871 G > A (9.1%), c.1360 C > T (3.0%), c.392 G > T (3.0%), and c.487 G > A (1.0%).

CONCLUSION

The incidence of G6PD deficiency in newborns in the Huizhou city was higher than the southern China average level, while the types and frequencies of gene mutations were found to vary slightly from other regions. Our findings suggested that free government screening and nearby diagnosis strategies could reduce the incidence of G6PD deficiency in the area.

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.

Molecular characterization of G6PD mutations identifies new mutations and a high frequency of intronic variants in Thai females

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked enzymopathy caused by mutations in the G6PD gene. A medical concern associated with G6PD deficiency is acute hemolytic anemia induced by certain foods, drugs, and infections. Although phenotypic tests can correctly identify hemizygous males, as well as homozygous and compound heterozygous females, heterozygous females with a wide range of G6PD activity may be misclassified as normal. This study aimed to develop multiplex high-resolution melting (HRM) analyses to enable the accurate detection of G6PD mutations, especially among females with heterozygous deficiency. Multiplex HRM assays were developed to detect six G6PD variants, i.e., G6PD Gaohe (c.95A>G), G6PD Chinese-4 (c.392G>T), G6PD Mahidol (c.487G>A), G6PD Viangchan (c.871G>A), G6PD Chinese-5 (c.1024C>T), and G6PD Union (c.1360C>T) in two reactions. The assays were validated and then applied to genotype G6PD mutations in 248 Thai females. The sensitivity of the HRM assays developed was 100% [95% confidence interval (CI): 94.40%-100%] with a specificity of 100% (95% CI: 88.78%-100%) for detecting these six mutations. The prevalence of G6PD deficiency was estimated as 3.63% (9/248) for G6PD deficiency and 31.05% (77/248) for intermediate deficiency by phenotypic assay. The developed HRM assays identified three participants with normal enzyme activity as heterozygous for G6PD Viangchan. Interestingly, a deletion in intron 5 nucleotide position 637/638 (c.486-34delT) was also detected by the developed HRM assays. G6PD genotyping revealed a total of 12 G6PD genotypes, with a high prevalence of intronic variants. Our results suggested that HRM analysis-based genotyping is a simple and reliable approach for detecting G6PD mutations, and could be used to prevent the misdiagnosis of heterozygous females by phenotypic assay. This study also sheds light on the possibility of overlooking intronic variants, which could affect G6PD expression and contribute to enzyme deficiency.

Glucose-6-phosphate dehydrogenase is dispensable for human erythroid cell differentiation in vitro

Glucose-6-phosphate dehydrogenase (G6PD) deficiency impairs cellular processes under oxidative stress. Individuals with severe G6PD deficiency still produce sufficient numbers of erythrocytes. Nevertheless, the G6PD independence of erythropoiesis remains questionable. This study elucidates the effects of G6PD deficiency on the generation of human erythrocytes. Peripheral blood-derived CD34-positive hematopoietic stem and progenitor cells (HSPCs) of human subjects with normal, moderate, and severe G6PD activities were cultured in two distinct phases: erythroid commitment and terminal differentiation. Regardless of G6PD deficiency, HSPCs were able to proliferate and differentiate into mature erythrocytes. There was no impairment in erythroid enucleation among the subjects with G6PD deficiency. To our knowledge, this study is the first report of effective erythropoiesis independent of G6PD deficiency. The evidence firmly indicates that the population with the G6PD variant could produce erythrocytes to an extent similar to that in healthy individuals.

Cytochrome P450 2D6 (CYP2D6) and glucose-6-phosphate dehydrogenase (G6PD) genetic variations in Thai vivax malaria patients: Implications for 8-aminoquinoline radical cure

BACKGROUND

Primaquine and tafenoquine are the only licensed drugs that effectively kill the hypnozoite stage and are used to prevent Plasmodium vivax malaria relapse. However, both primaquine and tafenoquine can cause acute hemolysis in glucose-6-phosphate dehydrogenase (G6PD)-deficient people with varying degrees of severity depending on G6PD variants. Additionally, primaquine efficacy against malaria parasites was decreased in individuals with impaired cytochrome P450 2D6 (CYP2D6) activity due to genetic polymorphisms. This study aimed to characterize G6PD and CYP2D6 genetic variations in vivax malaria patients from Yala province, a malaria-endemic area along the Thai-Malaysian border, and determine the biochemical properties of identified G6PD variants.

METHODOLOGY/PRINCIPLE FINDINGS

Multiplexed high-resolution melting assay and DNA sequencing detected five G6PD variants, including G6PD Kaiping, G6PD Vanua Lava, G6PD Coimbra, G6PD Mahidol, and G6PD Kerala-Kalyan. Biochemical and structural characterization revealed that G6PD Coimbra markedly reduced catalytic activity and structural stability, indicating a high susceptibility to drug-induced hemolysis. While Kerala-Kalyan had minor effects, it is possible to develop mild adverse effects when receiving radical treatment. CYP2D6 genotyping was performed using long-range PCR and DNA sequencing, and the phenotypes were predicted using the combination of allelic variants. Decreased and no-function alleles were detected at frequencies of 53.4% and 14.2%, respectively. The most common alleles were CYP2D6*36+*10 (25.6%), *10 (23.9%), and *1 (22.2%). Additionally, 51.1% of the intermediate metabolizers showed CYP2D6*10/*36+*10 as the predominant genotype (15.9%).

CONCLUSIONS/SIGNIFICANCE

Our findings provide insights about genetic variations of G6PD and CYP2D6 in 88 vivax malaria patients from Yala, which may influence the safety and effectiveness of radical treatment. Optimization of 8-aminoquinoline administration may be required for safe and effective treatment in the studied population, which could be a significant challenge in achieving the goal of eliminating malaria.

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.