Recent trends of glucose-6-phosphate dehydrogenase deficiency among saudi population in Riyadh city / Tendências recentes da deficiência de glicose-6-fosfato desidrogenase entre a população saudita na cidade de Riade

G6PD deficiency is associated with erythrocyte deficiency in the X-chromosome enzyme. It causes a hematologic syndrome called hemolytic anemia that connects G6PD deficiency with X-linked condition. In the Middle East, including Saudi Arabia, G6PD deficiency is the most dominant genetic blood disorders. It results in higher rates of mortality and morbidity due to its incurable long-lasting nature and prevalence of physical and psychological incapacities. In this study, an attempt was made to evaluate the prevalence of G6PD deficiency among the Saudi population in Riyadh city. A cross-sectional retrospective study was conducted at King Saud University Medical City in Riyadh, Saudi Arabia. The population of the study comprised randomly chosen males and females who visited the hospital from January 2017 to January 2018. Statistical analyses were performed using SPSS, and descriptive analysis was used to find the frequency of G6PD-deficient patients. Out of the 209 patients, 62.2% were males (n=130) and 37.8% were females (n=79). Twenty males and 6 females were found to have G6PD deficiency, with the male to female ratio being 1:3. Out of the total 130 male participants, 20 patients were found to be enzyme deficient and 6 patients of 79 female patients were found to be G6PD deficient. There were 38.4% (n=10) patients with G6PD level <4 units/gram hemoglobin, 26.9% (n=7) patients had G6PD levels of 4.1­7.0 units/gram hemoglobin, and 34.6% (n=9) patients had >7 units/gram hemoglobin. Among the G6PD patients, 23.07% patients were severely anemic, and 5 (19.2%) patients were reported to have high bilirubin. The present study revealed the G6PD prevalence to be 12.4% among the Saudi population; this value is significantly higher than that found in France, Spain, India, and Singapore. In the Saudi population, males are more vulnerable to G6PD-deficient than females. Hence, attention should be paid to G6PD-deficient patients while prescribing antimalarial medication. Such patients may be advised to avoid certain foods to minimize the risk of having hemolytic episodes.

A deficiência de G6PD está associada à deficiência de eritrócitos na enzima do cromossomo X. Causa uma síndrome hematológica chamada anemia hemolítica que conecta a deficiência de G6PD à condição ligada ao X. No Oriente Médio, incluindo a Arábia Saudita, a deficiência de G6PD é o distúrbio genético do sangue mais dominante. Isso resulta em maiores taxas de mortalidade e morbidade devido à sua natureza incurável e duradoura e à prevalência de incapacidades físicas e psicológicas. Neste estudo, foi feita uma tentativa de avaliar a prevalência de deficiência de G6PD entre a população saudita na cidade de Riade. Um estudo retrospectivo transversal foi realizado na cidade médica da Universidade King Saud, em Riade, na Arábia Saudita. A população do estudo compreendeu homens e mulheres escolhidos aleatoriamente que visitaram o hospital entre janeiro de 2017 e janeiro de 2018. As análises estatísticas foram realizadas com o SPSS e a análise descritiva foi utilizada para determinar a frequência de pacientes com deficiência de G6PD. Dos 209 pacientes, 62,2% eram do sexo masculino (n = 130) e 37,8% eram do sexo feminino (n = 79). Verificou-se que 20 homens e 6 mulheres apresentavam deficiência de G6PD, sendo a proporção homem/mulher de 1:3. Do total de 130 participantes do sexo masculino, 20 pacientes apresentaram deficiência de enzima e 6 de 79 pacientes do sexo feminino apresentaram deficiência de G6PD. Havia 38,4% (n = 10) pacientes com nível de G6PD < 4 unidades/grama de hemoglobina, 26,9% (n = 7) pacientes tinham níveis de G6PD de 4,1-7,0 unidades/grama de hemoglobina e 34,6% (n = 9) pacientes tinham > 7 unidades/grama de hemoglobina. Entre os pacientes com G6PD, 23,07% eram severamente anêmicos e cinco (19,2%) pacientes relataram ter alta bilirrubina. O presente estudo revelou que a prevalência de G6PD é de 12,4% na população saudita; esse valor é significativamente maior que o encontrado na França, Espanha, Índia e Cingapura. Na população saudita, os homens são mais vulneráveis à deficiência de G6PD do que as mulheres. Portanto, deve-se prestar atenção aos pacientes com deficiência de G6PD durante a prescrição de medicamentos antimaláricos. Esses pacientes podem ser aconselhados a evitar certos alimentos para minimizar o risco de episódios hemolíticos.

Molecular Cloning and Exploration of the Biochemical and Functional Analysis of Recombinant Glucose-6-Phosphate Dehydrogenase from Gluconoacetobacter diazotrophicus PAL5.

Gluconacetobacter diazotrophicus PAL5 (GDI) is an endophytic bacterium with potential biotechnological applications in industry and agronomy. The recent description of its complete genome and its principal metabolic enzymes suggests that glucose metabolism is accomplished through the pentose phosphate pathway (PPP); however, the enzymes participating in this pathway have not yet been characterized in detail. The objective of the present work was to clone, purify, and biochemically and physicochemically characterize glucose-6-phosphate dehydrogenase (G6PD) from GDI. The gene was cloned and expressed as a tagged protein in E. coli to be purified by affinity chromatography. The native state of the G6PD protein in the solution was found to be a tetramer with optimal activity at pH 8.8 and a temperature between 37 and 50 °C. The apparent Km values for G6P and nicotinamide adenine dinucleotide phosphate (NADP+) were 63 and 7.2 µM, respectively. Finally, from the amino acid sequence a three-dimensional (3D) model was obtained, which allowed the arrangement of the amino acids involved in the catalytic activity, which are conserved (RIDHYLGKE, GxGGDLT, and EKPxG) with those of other species, to be identified. This characterization of the enzyme could help to identify new environmental conditions for the knowledge of the plant-microorganism interactions and a better use of GDI in new technological applications.

Human red blood cell polymorphisms prevalent in Colombian population and its protective role against malaria.

The populations infected with malaria have developed genetic defense mechanisms in order to protect themselves against the most serious complications of this disease. Those mechanisms have been associated from the perspective of co-adaptive process with some genetic diseases widely present in humans as sickle-cell disease, sickle cell trait and glucose-6-phosphate dehydrogenase deficiency (G6PD). Biochemically, polymorphic mutations at the erythrocyte level have been widely studied, however there is no clear statement of the mechanisms used for resistance against the causative agent of malaria. The purpose of this review is to introduce the molecular and biochemical basis of defense mechanisms associated with two of those adaptations: sickle-cell trait and Glucose-6-phosphate Dehydrogenase Deficiency (G6PD). The first one is a hemoglobinopathy while the second one is the most frequent enzymopathy present in humans.

Cloning and biochemical characterization of three glucose­6­phosphate dehydrogenase mutants presents in the Mexican population.

The deficiency of glucose­6­phosphate dehydrogenase (G6PD) is one of the most common inborn errors of metabolism worldwide. This congenital disorder generally results from mutations that are spread throughout the entire gene of G6PD. Three single-point mutations for G6PD have been reported in the Mexican population and named Veracruz (Arg365His), G6PD Seattle (Asp282His), and G6PD Mexico DF (Thr65Ala), whose biochemical characterization have not yet been studied. For this reason, in this work we analyzed the putative role of the three mutations to uncover the functional consequences on G6PD activity. To this end, was developed a method to clone, overexpress, and purify recombinant human G6PD. The results obtained from all variants showed a loss of catalysis by 80 to 97% and had a decrease in affinity for both physiological substrates with respect to the wild type (WT) G6PD. Our results also showed that the three mutations affected three-dimensional structure and protein stability, suggesting an unstable structure with low conformational stability that affected its G6PD functionality. Finally, based on the biochemical characterization of the unclassified G6PD Mexico DF, we suggest that this variant could be grouped as a Class I variant, because biochemical data are similar with other Class I G6PDs.

Glucose-6-Phosphate Dehydrogenase: Update and Analysis of New Mutations around the World.

Glucose-6-phosphate dehydrogenase (G6PD) is a key regulatory enzyme in the pentose phosphate pathway which produces nicotinamide adenine dinucleotide phosphate (NADPH) to maintain an adequate reducing environment in the cells and is especially important in red blood cells (RBC). Given its central role in the regulation of redox state, it is understandable that mutations in the gene encoding G6PD can cause deficiency of the protein activity leading to clinical manifestations such as neonatal jaundice and acute hemolytic anemia. Recently, an extensive review has been published about variants in the g6pd gene; recognizing 186 mutations. In this work, we review the state of the art in G6PD deficiency, describing 217 mutations in the g6pd gene; we also compile information about 31 new mutations, 16 that were not recognized and 15 more that have recently been reported. In order to get a better picture of the effects of new described mutations in g6pd gene, we locate the point mutations in the solved three-dimensional structure of the human G6PD protein. We found that class I mutations have the most deleterious effects on the structure and stability of the protein.

Functional and Biochemical Characterization of Three Recombinant Human Glucose-6-Phosphate Dehydrogenase Mutants: Zacatecas, Vanua-Lava and Viangchan.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency in humans causes severe disease, varying from mostly asymptomatic individuals to patients showing neonatal jaundice, acute hemolysis episodes or chronic nonspherocytic hemolytic anemia. In order to understand the effect of the mutations in G6PD gene function and its relation with G6PD deficiency severity, we report the construction, cloning and expression as well as the detailed kinetic and stability characterization of three purified clinical variants of G6PD that present in the Mexican population: G6PD Zacatecas (Class I), Vanua-Lava (Class II) and Viangchan (Class II). For all the G6PD mutants, we obtained low purification yield and altered kinetic parameters compared with Wild Type (WT). Our results show that the mutations, regardless of the distance from the active site where they are located, affect the catalytic properties and structural parameters and that these changes could be associated with the clinical presentation of the deficiency. Specifically, the structural characterization of the G6PD Zacatecas mutant suggests that the R257L mutation have a strong effect on the global stability of G6PD favoring an unstable active site. Using computational analysis, we offer a molecular explanation of the effects of these mutations on the active site.