Glucose-6-Phosphate Dehydrogenase Deficiency Genetic Variants in Malaria Patients in Southwestern Ethiopia

Delineation of the role of G6PD in Alzheimer's disease and potential enhancement through microfluidic and nanoparticle approaches

Alzheimer's disease (AD) is a neurodegenerative pathologic entity characterized by the abnormal presence of tau and macromolecular Aβ deposition that leads to the degeneration or death of neurons. In addition to that, glucose-6-phosphate dehydrogenase (G6PD) has a multifaceted role in the process of AD development, where it can be used as both a marker and a target. G6PD activity is dysregulated due to its contribution to oxidative stress, neuroinflammation, and neuronal death. In this context, the current review presents a vivid depiction of recent findings on the relationship between AD progression and changes in the expression or activity of G6PD. The efficacy of the proposed G6PD-based therapeutics has been demonstrated in multiple studies using AD mouse models as representative animal model systems for cognitive decline and neurodegeneration associated with this disease. Innovative therapeutic insights are made for the boosting of G6PD activity via novel innovative nanotechnology and microfluidics tools in drug administration technology. Such approaches provide innovative methods of surpassing the blood-brain barrier, targeting step-by-step specific neural pathways, and overcoming biochemical disturbances that accompany AD. Using different nanoparticles loaded with G6DP to target specific organs, e.g., G6DP-loaded liposomes, enhances BBB penetration and brain distribution of G6DP. Many nanoparticles, which are used for different purposes, are briefly discussed in the paper. Such methods to mimic BBB on organs on-chip offer precise disease modeling and drug testing using microfluidic chips, requiring lower sample amounts and producing faster findings compared to conventional techniques. There are other contributions to microfluid in AD that are discussed briefly. However, there are some limitations accompanying microfluidics that need to be worked on to be used for AD. This study aims to bridge the gap in understanding AD with the synergistic use of promising technologies; microfluid and nanotechnology for future advancements.

Screening and the analysis of genotypic and phenotypic characterization of glucose-6-phosphate dehydrogenase (G6PD) deficiency in Fujian province, China

Introduction

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked hereditary disorder in southern China. However, the incidence rate of G6PD deficiency and the frequency of the most common G6PD gene variants vary widely. The purpose of this study was to investigate the prevalence, genotype, and phenotypic features of G6PD deficiency in neonates in Fujian province, southeastern China.

Methods

This retrospective cohort study enrolled 2,789,002 newborns (1,521,431 males and 1,267,571 females) based on the newborn screening program for G6PD deficiency in Fujian Province between January 2010 and December 2021.

Results

Of the 2,789,002 newborns enrolled, 26,437 cases were diagnosed (22,939 males and 3,498 females), and the estimated prevalence of G6PD deficiency in Fujian province was 0.95%. The prevalence was significantly higher among males (1.51%) than in females (0.28%) (p < 0.00001). Among the 3,198 patients with G6PD deficiency, 3,092 cases (2,145 males and 947 females) were detected to have G6PD gene variants. The top six prevalent genotypes identified represented 90.84% (2095/3,198) of the total and included c.1376G > T (44.93%), c.1388G > A (18.42%), c.1024C > T (9.32%), c.95A > G (8.69%), c.392G > T (5.25%), and c.871G > A (4.22%). The frequency of genotypes with c.1388G > A, c.1024C > T, and c.871G > A was higher in males in the Fujian province than in females, while the frequency of genotypes with c.1376G > T was lower. Furthermore, when comparing the enzyme activities of the top six prevalent genotypes, there were significant differences in the enzyme activities among the genotypes of male hemizygotes and female heterozygotes. According to the new classification of G6PD variants proposed by the World Health Organization (WHO), the variants with c.1376G > T, c.95A > G, and c.871G > A were recognized as Class A, while the c.392G > T, c.1388G > A, and c.1024C > T were recognized as Class B.

Discussion

To the best of our knowledge, this study is the first to systematically describe the overview of epidemiological characteristics of newborn G6PD deficiency in Fujian province, China, including the screening rate, incidence rate, and variant spectrum. Additionally, we elucidated the relationship between the distribution of enzyme activity with specific mutations and their WHO classification patterns. Our results could provide strategies for screening, diagnosis, and genetic counseling of G6PD deficiency in this area.

Genetic Variants Associated with the Risk of Stroke in Sickle Cell Anemia: Systematic Review and Meta-Analysis

Sickle cell anemia (SCA) is the most common cause of stroke in children. As it is a rare disease, studies investigating the association with complications like stroke in SCD have small sample sizes. Here, we performed a systematic review and meta-analysis of the studies exploring an association of genetic variants with stroke to get a better indication of their association with stroke. PubMed and Google Scholar were searched to identify studies that had performed an association analysis of genetic variants for the risk of stroke in SCA patients. After screening of eligible studies, summary statistics of association analysis with stroke and other general information were extracted. Meta-analysis was performed using the fixed effect method on the tool METAL and forest plots were plotted using the R program. The random effect model was performed as a sensitivity analysis for loci where significant heterogeneity was observed. 407 studies were identified using the search term and after screening 37 studies that cumulatively analyzed 11,373 SCA patients were included. These 37 studies included a total of 2,222 SCA patients with stroke, predominantly included individuals of African ancestry (N = 16). Three of these studies performed whole exome sequencing while 35 performed single nucleotide-based genotyping. Though the studies reported association with 132 loci, meta-analyses could be performed only for 12 loci that had data from two or more studies. After meta-analysis we observed that four loci were significantly associated with risk for stroke: -α3.7 kb Alpha-thalassemia deletion (P = 0.00000027), rs489347-TEK (P = 0.00081), rs2238432-ADCY9 (P = 0.00085), rs11853426-ANXA2 (P = 0.0034), and rs1800629-TNF (P = 0.0003396). Ethnic representation of regions with a high prevalence of SCD like the Mediterranean basin and India needs to be improved for genetic studies on associated complications like stroke. Larger genome-wide collaborative studies on SCD and associated complications including stroke need to be performed.

Prevalence of G6PD deficiency and distribution of its genetic variants among malaria-suspected patients visiting Metehara health centre, Eastern Ethiopia

Background

Glucose-6-phosphate dehydrogenase (G6PD) is cytosolic enzyme, which has a vital role for the integrity and functioning of red blood cells. Lower activity of this enzyme leads to the occurrence of acute haemolytic anaemia after exposure to oxidative stressors like primaquine. Primaquine is an important drug for the radical cure of Plasmodium vivax and blocking transmission of Plasmodium falciparum, and thereby enhancing malaria elimination. However, there is a need to identify G6PD deficient individuals and administer the drug with caution due to its haemolytic side effects. The main objective of this study is to determine the prevalence of G6PD deficiency among malaria-suspected individuals.

Methods

A facility-based cross-sectional study was conducted from September 2020 to September 2021 in Metehara Health Centre, Eastern Ethiopia. A structured questionnaire was used to collect the socio-demographic and clinical information of the study participants. Capillary and venous blood samples were collected based on standard procedures for onsite screening, dried blood spot preparation, and malaria microscopy. The G6PD enzyme activity was measured by careSTART™ G6PD biosensor analyzer. Data was entered and analysed by SPSS.

Results

A total of 498 study participants were included in the study, of which 62% (309) were males. The overall prevalence of G6PD deficiency based on the biosensor screening was 3.6% (18/498), of which 2.9% and 4.8% were males and females, respectively. Eleven of the G6PD deficient samples had mutations confirmed by G6PD gene sequencing analysis. Mutations were detected in G267 + 119C/T, A376T, and ChrX:154535443. A significant association was found in sex and history of previous malaria infection with G6PD deficiency.

Conclusions

The study showed that the G6PD deficient phenotype exists in Metehara even if the prevalence is not very high. G267 + 119C/T mutation is the predominant G6PD variant in this area. Therefore, malaria patient treatment using primaquine should be monitored closely for any adverse effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04269-5.

Spatial and genetic clustering of Plasmodium falciparum and Plasmodium vivax infections in a low-transmission area of Ethiopia

The distribution of malaria infections is heterogeneous in space and time, especially in low transmission settings. Understanding this clustering may allow identification and targeting of pockets of transmission. In Adama district, Ethiopia, Plasmodium falciparum and P. vivax malaria patients and controls were examined, together with household members and immediate neighbors. Rapid diagnostic test and quantitative PCR (qPCR) were used for the detection of infections that were genetically characterized by a panel of microsatellite loci for P. falciparum (26) and P. vivax (11), respectively. Individuals living in households of clinical P. falciparum patients were more likely to have qPCR detected P. falciparum infections (22.0%, 9/41) compared to individuals in control households (8.7%, 37/426; odds ratio, 2.9; 95% confidence interval, 1.3–6.4; P = .007). Genetically related P. falciparum, but not P. vivax infections showed strong clustering within households. Genotyping revealed a marked temporal cluster of P. falciparum infections, almost exclusively comprised of clinical cases. These findings uncover previously unappreciated transmission dynamics and support a rational approach to reactive case detection strategies for P. falciparum in Ethiopia.

Prevalence and distribution of G6PD deficiency: implication for the use of primaquine in malaria treatment in Ethiopia

BACKGROUND

G6PD enzyme deficiency is a common enzymatic X-linked disorder. Deficiency of the G6PD enzyme can cause free radical-mediated oxidative damage to red blood cells, leading to premature haemolysis. Treatment of Plasmodium vivax malaria with primaquine poses a potential risk of mild to severe acute haemolytic anaemia in G6PD deficient people. In this study, the prevalence and distribution of G6PD mutations were investigated across broad areas of Ethiopia, and tested the association between G6PD genotype and phenotype with the goal to provide additional information relevant to the use of primaquine in malaria treatment.

METHODS

This study examined G6PD mutations in exons 3-11 for 344 febrile patient samples collected from seven sites across Ethiopia. In addition, the G6PD enzyme level of 400 febrile patient samples from Southwestern Ethiopia was determined by the CareStart™ biosensor. The association between G6PD phenotype and genotype was examined by Fisher exact test on a subset of 184 samples.

RESULTS

Mutations were observed at three positions of the G6PD gene. The most common G6PD mutation across all sites was A376G, which was detected in 21 of 344 (6.1%) febrile patients. Thirteen of them were homozygous and eight were heterozygous for this mutation. The G267+119C/T mutation was found in 4 (1.2%) individuals in South Ethiopia, but absent in other sites. The G1116A mutation was also found in 4 (1.2%) individuals from East and South Ethiopia. For the 400 samples in the south, 17 (4.25%) were shown to be G6PD-deficient. G6PD enzyme level was not significantly different by age or gender. Among a subset of 202 febrile patients who were diagnosed with malaria, 11 (5.45%) were G6PD-deficient. These 11 infected samples were diagnosed with Plasmodium vivax by microscopy. Parasitaemia was not significantly different between the G6PD-deficient and G6PD-normal infections.

CONCLUSIONS

The prevalence of G6PD deficiency is modest among febrile patients in Ethiopia. G6PD deficiency testing is thus recommended before administrating primaquine for radical cure of P. vivax infected patients. The present study did not indicate a significant association between G6PD gene mutations and enzyme levels.

First detection of Anopheles stephensi Liston, 1901 (Diptera: culicidae) in Ethiopia using molecular and morphological approaches

Malaria is a major public health concern in Ethiopia. With the increase in malaria cases in the Somali Region of Ethiopia, understanding the distribution and identifying the species of malaria vectors is vital to public health. Here we report the first detection of Anopheles stephensi in Ethiopia, a malaria vector typically found in the Middle East, the Indian subcontinent, and China, but recently found in Djibouti. An entomological investigation was conducted during November to December 2016 in Kebri Dehar town of the Ethiopian Somali Regional State as ancillary work for Anopheles spp. surveillance. Mosquito larvae were collected from water reservoirs. Larvae were reared in the laboratory to the adult stage and identified morphologically. PCR and sequencing of cytochrome oxidase 1 (COI) and internal transcribed spacer 2 (ITS2) loci were performed. Basic Local Alignment Search Tool (BLAST) was used to compare sample sequences to sequences in the NCBI nucleotide database for species identification. To further analyze the relationship between the specimen we collected in Kebri Dehar and other Anopheles samples available in Genbank, phylogenetic analysis was performed using a maximum likelihood approach. Molecular and morphological results confirm specimens were An. stephensi. The closest high scoring hit was for all specimens was for the An. stephensi sequence. Independent phylogenetic analyses of COI and ITS2 sequences revealed in both cases strong bootstrap (100) support for our sequence forming a clade with other An. stephensi sequences to the exclusion of any other species of Anopheles. In conclusion, Anopheles stephensi is present in Kebri Dehar town in Ethiopia. These findings highlight the need for additional research to examine the role of An. stephensi in malaria transmission in Ethiopia.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency in Ethiopia: absence of common African and Mediterranean allelic variants in a nationwide study

BACKGROUND

Building on the declining trend of malaria in Ethiopia, the Federal Ministry of Health aims to eliminate malaria by 2030. As Plasmodium falciparum and Plasmodium vivax are co-endemic in Ethiopia, the use of primaquine is indicated for both transmission interruption and radical cure, respectively. However, the limited knowledge of the local prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency and its associated variants has hindered the use of primaquine.

METHODS

Some 11,138 dried blood spot (DBS) samples were collected in 2011 as part of a national, household Malaria Indicator Survey, a multi-stage nationally representative survey of all malaria-endemic areas of Ethiopia. A randomly selected sub-set of 1414 DBS samples was successfully genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Considering the geographical position and ethnic mix of the country, three common variants: G6PD*A (A376G), G6PD*A- (G202A) and Mediterranean (C563T) were investigated.

RESULTS

Of the 1998 randomly selected individuals, 1429 (71.5%) DBS samples were genotyped and merged to the database, of which 53.5% were from females. G6PD*A (A376G) was the only genotype detected. No sample was positive for either G6PD*A- (G202A) or Mediterranean (C563T) variants. The prevalence of G6PD*A (A376G) was 8.9% [95% confidence interval (CI) 6.7-11.2] ranging from 12.2% in the Southern Nations, Nationalities and Peoples' (95% CI 5.7-18.7) to none in Dire Dawa/Harari Region.

CONCLUSION

The common G6PD*A- (G202A) or Mediterranean (C563T) variants were not observed in this nationwide study. The observed G6PD*A (A376G) mutation has little or no clinical significance. These findings supported the adoption of primaquine for P. falciparum transmission interruption and radical cure of P. vivax in Ethiopia. As the presence of other clinically important, less common variants cannot be ruled out, the implementation of radical cure will be accompanied by active haematological and adverse events monitoring in Ethiopia.

Glucose-6-phosphate dehydrogenase activity measured by spectrophotometry and associated genetic variants from the Oromiya zone, Ethiopia

BACKGROUND

The study aimed to gain first data on the prevalence of G6PD enzyme deficiency measured by spectrophotometry and associated genetic variants in Jimma and surroundings, Ethiopia. The area is a Plasmodium vivax endemic region, but 8-aminoquinolines such as primaquine are not recommended as G6PD testing is not available.

METHODS

Healthy volunteers were recruited at Jimma University, Ethiopia. Enzyme activity was tested by spectrophotometry at the University of Ulm, Germany. A G6PD RDT (Binax NOW^® G6PD, Alere, USA) was additionally performed. The G6PD gene was analysed for polymorphisms in a sub-population. Tests for haemoglobinopathies and the presence of malaria parasites were conducted.

RESULTS

No severe or moderate (cut-off 60%) G6PD deficiency was found in 206 volunteers. Median male activity was 6.1 U/g Hb. Eleven participants (5.4%) showed activities between 70 and 80%. No haemoglobinopathy was detected. None of the subjects showed asymptomatic parasitaemia. One G6PD-A+ variant (A376G) and one new non-synonymous mutation (G445A) were found.

CONCLUSIONS

As the prevalence of G6PD deficiency seems low in this area, the use of 8-aminoquinolines should be encouraged. However, reliable G6PD testing methods have to be implemented and safe cut-off levels need to be defined.

Glucose-6-phosphate dehydrogenase deficiency allelic variants and their prevalence in malaria patients in Eritrea

Introduction

Glucose 6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy with a relatively high frequency in malaria-endemic regions. In Eritrea, there is scanty knowledge of G6PD deficiency. The aim of the study was to characterize and determine the prevalence of four common G6PD allelic variants.

Methods

Three hundred and fourteen dried blood spot samples from unrelated microscopically diagnosed malaria patient Eritrean ethnic groups living in five zobas (regions) of Eritrea were analysed by PCR-RFLP method to identify the G6PD B, G6PD A (A376G), G6PD A-(G202A), and G6PD Mediterranean (C563T) variants. To confirm the RFLP results, samples positive for A376G but negative for G202A variants were subjected to Sanger sequencing and a subset of PCR products (exon 5) directly sequenced to identify A376G and other mutations.

Results

For G6PD genotyping, G6PD B was detected in 87.5% and A376G detected in 12.5% of malaria patients, whereas G202A and C563T were absent. Bivariate Statistical analysis showed a statistically significant association between G6PD genotypes and zoba (P < 0.004 < 0.05). Sequencing revealed the expected A376G variant. In exon 5, four common (A376G) mutations, three uncommon mutations rs782669677 (535G→A) and one potentially new mutation (451G→C), relative to the reference, mRNA NM_001042351 were detected. Bioinformatic analysis of these mutations' potential functional impact suggests minimal effect on protein function.

Conclusion

This is the first report indicating that G6PD B and G6PD A genotypes are prevalent in Eritrea. Similar findings were reported in neighboring countries. Further studies including phenotype analysis are needed to corroborate the observed results.

Low and heterogeneous prevalence of glucose-6-phosphate dehydrogenase deficiency in different settings in Ethiopia using phenotyping and genotyping approaches

BACKGROUND

8-Aminoquinolines such as primaquine clear mature Plasmodium falciparum gametocytes that are responsible for transmission from human to mosquitoes and bring radical cure in Plasmodium vivax by clearing dormant liver stages. Deployment of primaquine is thus of relevance for malaria elimination efforts but challenged by the widespread prevalence of glucose-6-phosphate dehydrogenase deficiency (G6PDd) in endemic countries since primaquine in G6PDd individuals may lead to acute haemolysis. In this study, the prevalence of G6PDd was investigated in different settings in Ethiopia using phenotyping and genotyping approaches.

METHODS

Community and school based cross-sectional surveys were conducted from October to December 2016 in four administrative regions (Gambela, Benishangul Gumuz, Oromia, and Amhara) in Ethiopia. Finger prick blood samples were collected for G6PD enzyme activity using the CareStart™ G6PD screening test and genotyping of 36 selected single nucleotide polymorphisms (SNPs) located in the G6PD gene and its flanking regions.

RESULTS

Overall, the prevalence of phenotypic G6PDd was 1.4% (22/1609). For the first time in the Ethiopian population, the African variant (A-) was detected in 3.5% (7/199) of the limited set of genotyped samples, which were all phenotypically normal. Interestingly, all of these individuals had a variation at the rs2515904 locus. Strong geographical variation was observed for both phenotypic and genotypic G6PDd; three-quarters of the phenotypically G6PDd individuals were detected in Gambela.

CONCLUSION

A very low prevalence of G6PDd was detected in the present study populations. The presence of the A- variant alongside other G6PD mutants and the patchy distribution of G6PDd indicate that larger studies specifically designed to unravel the distribution of G6PDd at small geographical scale may be needed to tailor malaria elimination efforts in Ethiopia to the local context.