Prevalence of glucose-6-phosphate dehydrogenase deficiency in Cameroonian blood donors

First Insight into Drug Resistance Genetic Markers, Glucose-6-Phosphate Dehydrogenase and Phylogenetic Patterns of Misdiagnosed Plasmodium vivax Malaria in Far North Region, Cameroon

Plasmodium falciparum (Pf) is the predominant malaria species in Africa, but growing rates of non-falciparum species such as P. vivax (Pv) have been reported recently. This study aimed at characterizing drug resistance genes, glucose-6-phosphate dehydrogenase gene (G6PD), and phylogenetic patterns of a Pv + Pf co-infection misdiagnosed as a Pf mono-infection in the Far North region of Cameroon. Only one non-synonymous mutation in the pvdhps gene A383G was found. Pv drug resistance gene sequences were phylogenetically closer to the reference SAL-I strain and isolates from Southeast Asia and Western Pacific countries. Analyzing co-infecting Pf revealed no resistance mutations in Pfmdr1 and Pfk13 genes, but mutations in Pfcrt (C72V73I74E75T76) and Pfdhfr-Pfdhps genes (A16C50I51R59N108L164 - A436A437K540G581S613) were observed. No G6PD deficiency-related mutations were found. This is first study from Cameroon reporting presence of putative drug resistance mutations in Pv infections, especially in the pvdhps gene, and also outlined the absence of a G6PD-deficiency trait in patients.

Prevalence of Glucose-6-Phosphate Dehydrogenase Deficiency in Male Newborn Infants and Its Relationship with Neonatal Jaundice in Thailand

OBJECTIVE

 The study aimed to explore the prevalence of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency among male newborn infants in northeastern Thailand and its relationship with neonatal jaundice (NJ).

STUDY DESIGN

 This prospective cohort study included male newborn infants with gestational age (GA) ≥35 weeks born between July 1, 2019, and March 1, 2021. Cord blood was sent for G-6-PD fluorescent spot test (FST) and results were reported as normal, partial, or complete deficiency. Infants with NJ would have blood tested for total serum bilirubin (TSB) level and other possible causes of NJ. Duration of phototherapy, length of hospital stays, and complications were documented.

RESULTS

 There were 922 male infants included in this study with 854 (93.1%) term and 63 (6.9%) preterm infants. FST showed 132 infants (14.4%) had G-6-PD deficiency. Incidence of NJ was significantly higher among infants with G-6-PD deficiency compared with infants with normal G-6-PD level (47.7 vs. 25.8%; relative risk [RR]: 2.62, 95% confidence interval [CI]: 1.79-3.82; p < 0.001). Regardless of G-6-PD level, preterm infants had significantly higher incidence of NJ than term infants (52.4 vs. 27.3%; RR: 2.93, 95% CI: 1.75-4.92; p < 0.001). Duration of phototherapy was significantly longer in infants with G-6-PD deficiency with NJ but hospital stays were similar. Infants with combined G-6-PD deficiency and other causes of hemolysis did not have higher TSB level than infants with isolated G-6-PD deficiency. Risk factors associated with NJ were G-6-PD deficiency and preterm infants, whereas more advance GA was associated with reduced risk for NJ.

CONCLUSION

 G-6-PD deficiency and preterm infants were important risk factors for NJ. Routine G-6-PD screening, close monitoring for signs of NJ in infant with risks, and appropriate parental counseling should be implemented.

KEY POINTS

· G-6-PD deficiency increases risk of neonatal jaundice.. · Preterm infants have higher risk for neonatal jaundice.. · G-6-PD deficiency does not link with severe jaundice..

Low Density Plasmodium Infections and G6PD Deficiency Among Malaria Suspected Febrile Individuals in Ethiopia

The identification and management of low parasitemia infections have become increasingly challenging for malaria control and elimination. Submicroscopic Plasmodium infections and G6PD deficiency among febrile patients require more sensitive diagnostic methods to improve detection and careful treatment regime of these infections. In Ethiopia, information on the low density submicroscopic malarial infections and frequency of G6PD deficiency (G6PDd) is scarce. In this study, 297 malaria suspected febrile patient samples were collected from health facilities of Bonga town in southwestern Ethiopia. The positivity rates of Plasmodium infection were determined by microscopy and quantitative PCR. G6PD activity level was determined by careSTART^™ G6PD biosensor and the frequency of three common variants: G6PD*A (A376G), G6PD*A- (G202A) and Mediterranean (C563T) were investigated. G6PD gene sequencing was performed to detect mutations in exons 2-11 for both G6PD normal and deficient samples based on the phenotypic assay. More than twice Plasmodium infected samples was detected by qPCR (52/297; 17.4%) than microscopy (21/297; 7.0%). About 31 (10%) of the infections were submicroscopic. Bednet usage and age had a significant association with Plasmodium infection. Of the 271 participants who were tested for G6PD phenotype, 19 (7.0%) had low G6PD level. No mutations were observed in A376G, G202A, and C563T in the G6PDd samples, but three novel non-synonymous mutations in exon 2 including a C to T transition at position ChrX:6504 (Arg to Thr), G to T at ChrX:6369 (Ser to IIe), and G to C at ChrX:6664 (Gln to His) were detected. A high number of submicroscopic Plasmodium infections observed in this study pose a challenge for accurate and timely diagnosis, which could hinder malaria control efforts. G6PD deficiency in malaria patients pose danger when treating patients with primaquine. The three novel mutations detected in exon 2 of the G6PD gene merit further investigation on the hemolytic risk when exposed to oxidative antimalarials, their prevalence, and clinical significance.

The ethnogeographic variability of genetic factors underlying G6PD deficiency

Glucose-6-phosphate dehydrogenase (G6PD) deficiency caused by genetic variants in the G6PD gene, constitutes the most common enzymopathy worldwide, affecting approximately 5% of the global population. While carriers are mostly asymptomatic, they are at substantial risk of acute hemolytic anemia upon certain infections or exposure to various medications. As such, information about G6PD activity status in a given patient can constitute an important parameter to guide clinical decision-making. Here, we leveraged whole genome sequencing data from 142,069 unrelated individuals across seven human populations to provide a global comprehensive map of G6PD variability. By integrating established functional classifications with stringent computational predictions using 13 partly orthogonal algorithms for uncharacterized and novel variants, we reveal the large extent of ethnogeographic variability in G6PD deficiency and highlight its population-specific genetic composition. Overall, estimated disease prevalence in males ranged between 12.2% in Africans, 2.7-3.5% across Asia and 2.1% in Middle Easterners to < 0.3% in Europeans, Finnish and Amish. In Africans, the major deficient alleles were A-^202A/376 G (minor allele frequency 11.6%) and A-^{968 C/376 G} (0.5%). In contrast, G6PD deficiency in Middle Easterners was primarily due to the Mediterranean allele (1.3%) and the population-specific Cairo variant (0.4%). In South Asia, the most prevalent deficient alleles were Mediterranean (1.7%), Kerala (1.1%), Gond (0.9%) and Orissa (0.2%), whereas in East Asian populations the Canton (1.1%), Kaiping (0.7%) and Viangchan (0.3%) variants were predominant. Combined, our analyses provide a large dataset of G6PD variability across major ethnogeographic groups and can instruct population-specific genotyping strategies to optimize genetically guided therapeutic interventions.

Dosage Compensation in Females with X-Linked Metabolic Disorders

Through the use of new genomic and metabolomic technologies, our comprehension of the molecular and biochemical etiologies of genetic disorders is rapidly expanding, and so are insights into their varying phenotypes. Dosage compensation (lyonization) is an epigenetic mechanism that balances the expression of genes on heteromorphic sex chromosomes. Many studies in the literature have suggested a profound influence of this phenomenon on the manifestation of X-linked disorders in females. In this review, we summarize the clinical and genetic findings in female heterozygotic carriers of a pathogenic variant in one of ten selected X-linked genes whose defects result in metabolic disorders.

Glucose-6-Phosphate Acts as an Extracellular Signal of SagS To Modulate Pseudomonas aeruginosa c-di-GMP Levels, Attachment, and Biofilm Formation

In Pseudomonas aeruginosa, the orphan two-component sensor SagS contributes both to transition to biofilm formation and to biofilm cells gaining their heightened tolerance to antimicrobials. However, little is known about the identity of the signals or conditions sensed by SagS to induce the switch to the sessile, drug-tolerant mode of growth. Using a modified Biolog phenotype assay to screen for compounds that modulate attachment in a SagS-dependent manner, we identified glucose-6-phosphate to enhance attachment in a manner dependent on the glucose-6-phosphate concentration and SagS. The stimulatory effect was not limited to the attachment since glucose-6-phosphate likewise enhanced biofilm formation and also enhanced the expression of select biofilm marker genes. Moreover, exposure to glucose-6-phosphate coincided with decreased swarming motility but increased cellular cyclic-di-GMP (c-di-GMP) levels in biofilms. No such response was noted for compounds modulating attachment and biofilm formation in a manner independent of SagS. Modulation of c-di-GMP in response to glucose-6-phosphate was due to the diguanylate cyclase NicD, with NicD also being required for enhanced biofilm formation. The latter was independent of the sensory domain of NicD but dependent on NicD activity, SagS, and the interaction between NicD and SagS. Our findings indicate that glucose-6-phosphate likely mimics a signal or conditions sensed by SagS to activate its motile-sessile switch function. In addition, our findings provide new insight into the interfaces between the ligand-mediated two-component system signaling pathway and c-di-GMP levels.IMPORTANCE Pathogens sense and respond to signals and cues present in their environment, including host-derived small molecules to modulate the expression of their virulence repertoire. Here, we demonstrate that the opportunistic pathogen Pseudomonas aeruginosa responds to glucose-6-phosphate. Since glucose-6-phosphate is primarily made available due to cell lysis, it is likely that glucose-6-phosphate represents a cross-kingdom cell-to-cell signal that enables P. aeruginosa to adapt to the (nutrient-poor) host environment by enhancing biofilm formation, cyclic-di-GMP, and the expression of genes linked to biofilm formation in a concentration- and SagS-dependent manner.

Traditional African remedies induce hemolysis in a glucose-6-phopshate dehydrogenase deficient zebrafish model

Traditional remedies are widely used throughout Africa in routine care for infants. However, such remedies could have detrimental effects. Acute bilirubin encephalopathy (ABE) and kernicterus spectrum disorder (KSD) are common newborn health conditions in the developing world, contributing to substantial neonatal mortality and morbidity. They frequently occur in children with glucose-6-phopshate dehydrogenase (G6PD) deficiency. Using our established zebrafish model of G6PD deficiency, we tested the effects of three traditional compounds used in the care of the newborn umbilical cord: eucalyptus oil, methylated spirits, and Yoruba herbal tea. We found that eucalyptus oil induced a 13.4% increase in a hemolytic phenotype versus control, while methylated spirits showed a 39.7% increase in affected phenotype. Yoruba herbal tea exposure showed no effect. While methylated spirits are already a known pro-oxidant, these data indicate that eucalyptus oil may also be a hemolytic trigger in those with G6PD deficiency. Discovering which agents may contribute to the pathophysiology of G6PD deficiency is critical to eliminate ABE and KSD, especially in countries with a high prevalence of G6PD deficiency. The next step in elucidating the role of these agents is to determine the clinical correlation between the use of these agents and ABE/KSD.