Genetic Variants of Glucose-6-Phosphate Dehydrogenase and Their Associated Enzyme Activity: A Systematic Review and Meta-Analysis.

Low glucose-6-phosphate dehydrogenase enzyme (G6PD) activity is a key determinant of drug-induced haemolysis. More than 230 clinically relevant genetic variants have been described. We investigated the variation in G6PD activity within and between different genetic variants. In this systematic review, individual patient data from studies reporting G6PD activity measured by spectrophotometry and corresponding the G6PD genotype were pooled (PROSPERO: CRD42020207448). G6PD activity was converted into percent normal activity applying study-specific definitions of 100%. In total, 4320 individuals from 17 studies across 10 countries were included, where 1738 (40.2%) had one of the 24 confirmed G6PD mutations, and 61 observations (3.5%) were identified as outliers. The median activity of the hemi-/homozygotes with A-(c.202G>A/c.376A>G) was 29.0% (range: 1.7% to 76.6%), 10.2% (range: 0.0% to 32.5%) for Mahidol, 16.9% (range 3.3% to 21.3%) for Mediterranean, 9.0% (range: 2.9% to 23.2%) for Vanua Lava, and 7.5% (range: 0.0% to 18.3%) for Viangchan. The median activity in heterozygotes was 72.1% (range: 16.4% to 127.1%) for A-(c.202G>A/c.376A>G), 54.5% (range: 0.0% to 112.8%) for Mahidol, 37.9% (range: 20.7% to 80.5%) for Mediterranean, 53.8% (range: 10.9% to 82.5%) for Vanua Lava, and 52.3% (range: 4.8% to 78.6%) for Viangchan. A total of 99.5% of hemi/homozygotes with the Mahidol mutation and 100% of those with the Mediterranean, Vanua Lava, and Viangchan mutations had <30% activity. For A-(c.202G>A/c.376A>G), 55% of hemi/homozygotes had <30% activity. The G6PD activity for each variant spanned the current classification thresholds used to define clinically relevant categories of enzymatic deficiency.

Genetic predisposition in type 2 diabetes: A promising approach toward a personalized management of diabetes.

Diabetes mellitus, also known simply as diabetes, has been described as a chronic and complex endocrine metabolic disorder that is a leading cause of death across the globe. It is considered a key public health problem worldwide and one of four important non-communicable diseases prioritized for intervention through world health campaigns by various international foundations. Among its four categories, Type 2 diabetes (T2D) is the commonest form of diabetes accounting for over 90% of worldwide cases. Unlike monogenic inherited disorders that are passed on in a simple pattern, T2D is a multifactorial disease with a complex etiology, where a mixture of genetic and environmental factors are strong candidates for the development of the clinical condition and pathology. The genetic factors are believed to be key predisposing determinants in individual susceptibility to T2D. Therefore, identifying the predisposing genetic variants could be a crucial step in T2D management as it may ameliorate the clinical condition and preclude complications. Through an understanding the unique genetic and environmental factors that influence the development of this chronic disease individuals can benefit from personalized approaches to treatment. We searched the literature published in three electronic databases: PubMed, Scopus and ISI Web of Science for the current status of T2D and its associated genetic risk variants and discus promising approaches toward a personalized management of this chronic, non-communicable disorder.

Molecular Understanding of Severe Cases of ß-Thalassemia in the Nablus Region, West Bank, Palestine.

Hemoglobinopathies are common inherited monogenic diseases that are likely to remain a serious regional health problem where thalassemias and sickle cell disease are prevalent. In regions where recessive alleles for hemoglobinopathy disorders are present with high consanguinity rates, such as in Palestine, coinheritance of two different genetic defects becomes anticipated and prevalent. In this report, we characterize the molecular variants of the HBB gene for 16 patients with transfusion-dependent anemia registered at the Thalassemia Patient Friends Society in Nablus governorate, West Bank, Palestine. Analysis revealed that 63.0% (10/16) of the patients were homozygous for ß-thalassemia (ß-thal), IVS-I-6 (T>C) (HBB: c.92+6T>C) or IVS-I-110 (G>A) (HBB: c.93-21G>A); 19.0% (3/16) homozygous for sickle cell disease or Hb S (HBB: c.20A>T, p.Glu6Val); 13.0% (2/16) were double heterozygotes for Hb S/ß-thal, (HBB: c.20A>T/HBB: c.92G>C) and HBB: c.20A>T/HBB: c.321_322insG; and one case was a compound heterozygote for ß-thal, codon 39 (C>T) (HBB: c.118C>T) and IVS-I-110. The most common mutation reported in the 16 patients was IVS-I-6 (0.38), followed by IVS-I-110 (0.28) Hb S (0.25) and 0.03 each for codon 39, codons 106/107 (HBB: c.321_322insG) and Hb Monroe (HBB: c.92G>C). In conclusion, in Palestine, a variety of intricate inheritance patterns are encountered in clinical practice.

The effect of vitamin C and/or E supplementations on type 2 diabetic adult males under metformin treatment: A single-blinded randomized controlled clinical trial.

BACKGROUND AND AIM: Recently, there has been an increasing interest in the influence of antioxidant vitamins on the efficacy of oral hypoglycemic therapy in type 2 diabetic patients (T2DM). This single-blinded randomized controlled clinical trial aimed to investigate the effect of vitamin C and/or E supplementation on the efficacy of oral hypoglycemic therapy in T2DM Palestinian male patients from the Gaza Strip. METHODS: Forty T2DM male patients aged 40-60 years on metformin treatment were randomly divided into four groups, each group received an additional one of the following daily oral supplements for 90 days: placebo; vitamin C; vitamin E and vitamin C plus vitamin E. After overnight fasting, venous blood specimens were collected from all individuals into K3-EDTA tubes and serum tubes for measuring the biochemical and hematological parameters of the study at baseline and after 90 days of vitamins supplementation. RESULTS: The results revealed that vitamin C and/or E improve fasting blood sugar (FBS), HbA1c, lipid profile, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), reduced glutathione (GSH); and Quantitative Insulin Sensitivity Check Index (QISCI) compared with diabetic patients group that received placebo. CONCLUSION: This study provided additional evidence on the beneficial effects of supplementing antioxidant vitamins in T2DM which could improve the clinical condition and attenuate or prevent diabetic pathogenesis and complications that, secondly to poor glycemic control, could attribute to the imbalance between the decline in the endogenous antioxidants and increasing production of the reactive oxygen species leading to the oxidant-mediated damage present in the diabetic context.

Possible association of 3' UTR +357 A>G, IVS11-nt 93 T>C, c.1311 C>T polymorphism with G6PD deficiency.

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked inherited enzymopathic disorder affecting more than 500 million people worldwide. It has so far been linked to 217 distinct genetic variants in the exons and exon-intron boundaries of the G6PD gene, giving rise to a wide range of biochemical heterogeneity and clinical manifestations. OBJECTIVES: Reports from different settings suggested the association of intronic and other mutations outside the reading frame of the G6PD gene with reduced enzyme activity and presenting clinical symptoms. The present study aimed to investigate any association of other variations apart of the exonic or exonic intronic boundaries in the development of G6PD deficiency. METHODS: Sixty-seven unrelated Palestinian children admitted to the pediatric hospital with hemolytic crises due to G6PD deficiency were studied. RESULTS: In our Palestinian cohort of 67 [59 males (M) and 8 females (F)] G6PD-deficient children, previously hospitalized for acute hemolytic anemia due to favism, molecular sequencing of the G6PD gene revealed four cases (3M and 1F) that did not have any of the variants known to cause G6PD deficiency, but the 3' UTR c.*+357A>G (rs1050757) polymorphism in association with IVS 11 (c.1365-13T>C; rs2071429), and c.1311C>T (rs2230037). CONCLUSION: We now provide an additional evidence form Palestinian G6PD-deficient subjects for a possible role of 3' UTR c.*+357 A>G, c.1365-13T>C, and/or c.1311C>T polymorphism for G6PD deficiency, suggesting that not only a single variation in the exonic or exonic intronic boundaries, but also a haplotype of G6PD should considered as a cause for G6PD deficiency.

Favism, the commonest form of severe hemolytic anemia in Palestinian children, varies in severity with three different variants of G6PD deficiency within the same community.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common genetic abnormality known to predispose to acute hemolytic anemia (AHA), which can be triggered by certain drugs or infection. However, the commonest trigger is fava beans (Vicia faba) ingestion, causing AHA (favism), which may be life-threatening especially in children. G6PD deficiency is genetically highly heterogeneous, as nearly 200 different mutations have been observed. We have investigated the hematological features of acute favism in the Palestinian Gaza community that is characterized by the polymorphic coexistence of three different G6PD deficiency genes (G6PD A-, G6PD Cairo, G6PD Med). We have found by comparison to the general population (485 adults and 466 newborns) that children with favism, in terms of relative frequency, G6PD A- was under-represented, whereas G6PD Med was over-represented. We also found that the severity of anemia was significantly greater with G6PD Med and G6PD Cairo than with G6PD A-; and with G6PD Cairo, compared to the other two variants, there was greater hyperbilirubinemia, as well as persistence of mild anemia and reticulocytosis for as long as 4months after recovery from favism. This is the first report determining a differential impact of different G6PD mutations on the clinical features of favism in the same population and the same environment.

Protective and therapeutic effectiveness of taurine in diabetes mellitus: a rationale for antioxidant supplementation.

Taurine, 2-amino ethanesulfonic acid, is a conditionally essential ß amino acid which is not utilized in protein synthesis. Taurine is one of the most abundant free amino acids in mammals tissues and is one of the three well-known sulfur-containing amino acids; the others are methionine and cysteine which are considered as the precursors for taurine synthesis. Different scientific studies emphasize on the cytoprotective properties of taurine which included antioxidation, antiapoptosis, membrane stabilization, osmoregulation, and neurotransmission. Protective and therapeutic ameliorations of oxidative stress-induced pathologies were also attributed to taurine both in experimental and human models. Data demonstrating the beneficial effectiveness of taurine against type 1 and type 2 diabetes mellitus and their complications are growing and providing a better understanding of the underlying molecular mechanisms. Although the clinical studies are limited compared to the experimental ones, the present updated systematic review of the literature is set up to provide experimental and clinical evidences regarding the effectiveness of taurine in the context of diabetes mellitus and its complications. Gathering these scientific effects of taurine on diabetes mellitus could provide the physicians and specially the endocrinologists with a comprehensive overview on possible trends in the prevention and management of the disease and its complications through antioxidant supplementation.

Consanguinity profile in the Gaza Strip of Palestine: large-scale community-based study.

Consanguineous marriages which have been practiced throughout history continue to be practiced within different ethnic, religious and social groups to varying degrees with highest prevalences in North Africa, Middle East and central and south Asia. In the Gaza Strip of Palestine, little is known about the consanguinity profile, so the present large-scale study aims to explore the consanguinity profile of two generations using data from the ß-thalassemia premarital screening program. Sociodemographic data analysis included 156,635 (141,200 males and 15,435 females) persons and their parents, representing 141,200 couples who were referred to the Thalassemia and Hemophilia Center for premarital testing. In addition, the consanguinity characteristics of parents of 217 transfusion-dependent ß-thalassemic non-sibling patients were analyzed. Results revealed a significant decrease in the overall prevalence of consanguineous (first- and second-cousin) marriages between the previous (fathers') generation (45.2%) and the current (groom/bride) generation (39.9%). Among the five governorates of the Gaza Strip, records of Gaza Governorate revealed the lowest occurrence (36.9% current generation and 42.1% previous generation) of consanguineous marriages, as compared to all others. Consanguineous marriages are significantly higher in semi-urban areas (41.6%) than in urban areas (39.1%) in the current generation (previous generation, 46.4% vs 44.7%, respectively). Compound consanguinity (two generation) and a single level of consanguinity were seen in 20.7% and 43.7%, respectively, of the cases. The average age of those with first-cousin marriages is significantly lower (22.4±4.4 years) than those with second-cousin marriages (24.3±6.1 years) and the non-consanguineous (26.5±8.2 years). The rate of consanguineous marriages among never married people (42.2%) is significantly much higher than the rate of people with multiple marriages (18.1%). About 74.7% of the non-sibling thalassemic patients of the Gaza Strip are associated with consanguineous parents, of them 54.4% first-cousins and 20.3% second-cousins. In conclusion, although there is a decline in the consanguinity profile in the present compared to previous generation, consanguineous marriages are still a common practice in the Gaza Strip, which rationalizes the necessity for more awareness and counseling efforts about the potential health-related risks of consanguinity on individual lives and the population overall.

Detection of nine Mediterranean ß-thalassemia mutations in Palestinians using three restriction enzyme digest panels: a reliable method for developing countries.

ß-Thalassemia (ß-thal) is a public health problem in the Gaza Strip, Palestine, where about 320 patients are currently managed through blood transfusions and iron chelation. Within the restrictive environment of the Gaza Strip, no advanced molecular analysis [sequencing, real-time polymerase chain reaction (real-time PCR)] technology is currently available for developing a premarital screening protocol and providing couples at risk with prenatal diagnosis. Therefore, genetic identification of samples with indicators of ß-thal is delayed for weeks before the samples can be sequenced outside the country. As nine causative mutations have been identified in the majority of ß-thal cases in the Gaza Strip, a basic genetic screening strategy was designed to improve timeliness in mutation identification and reduce costs to the Palestinian health system. In the present study, we developed a reliable method for the detection of nine Mediterranean ß-thal mutations common to the Palestinian population using a panel of restriction enzyme digests. This strategy utilizes standard instrumentation (thermocycler and agarose gel electrophoresis) that would be available in any basic molecular genetics or biochemical laboratory and provides a reliable method of genetic screening and counseling for patients at risk for ß-thal.

The spectrum of ß-thalassemia mutations in Gaza Strip, Palestine.

BACKGROUND: ß-Thalassemia is a disorder caused by mutations at the hemoglobin ß-gene (HBB) locus. Its most important manifestation, the major form, is characterized by severe hypochromic and hemolytic anemia and is inherited in an autosomal recessive mode. In Gaza Strip, Palestine 0.02% of the population has been identified as ß-thalassemia major. DESIGN AND METHODS: An assessment of mutations was performed in 49 transfusion dependent patients with ß-thalassemia major and in 176 ß-thalassemia carriers diagnosed with a mean erythrocyte cell volume (MCV) <80fl and a proportion of HbA2>3.5%. In addition 39 individuals suspicious for ß-thalassemia carrier status due to a reduced MCV (<80fl) but a normal HBA2 were screened. RESULTS: By screening with three hybridization assays a proportion of 80% of the thalassemic chromosomes from patients and carriers was identified to carry five different mutations of the hemoglobin (Hb) ß-gene. Subsequent DNA sequencing confirmed these and revealed further 9% of the chromosomes to be affected by other mutations. In addition six chromosomes from suspicious carriers were detected to carry ß-thalassemia mutations. Of the 15 different HBB mutations identified the variant IVS-I-110 G>A was the most frequent mutation identified in 34% of the thalassemic chromosomes, followed by IVS-I-1 G>A, IVS-I-6 T>C, Codon 39 C>T, and Codon 37 G>A. Three novel HBB variants were discovered by direct sequencing of the gene: 5' UTR-50 (-/G), 5' UTR-43 C>T, and IVS-II-26 T>G. CONCLUSIONS: The spectrum of HBB mutations described is of the Mediterranean type whereby the allele frequencies of the most common mutations differ from those, which were previously described for the population of the Gaza Strip and other Palestinian populations. The data presented may promote the introduction of molecular testing to the Palestinian premarital screening program for ß-thalassemia in Gaza Strip, which will improve the screening protocol and genetic counseling in the future.

The reliability of the National Cholesterol Education Program's Adult Treatment Panel III (NCEP/ATP III) and the International Diabetes Federation (IDF) definitions in diagnosing metabolic syndrome (MetS) among Gaza Strip Palestinians.

OBJECTIVES: Metabolic syndrome (MetS) which is a multifaceted syndrome, has been demonstrated as a common precursor for developing cardiovascular diseases and/or type 2 diabetes mellitus. Different diagnostic definitions for MetS have been proposed and recommended. We set up to evaluate the reliabilities of the National Cholesterol Education Program's Adult Treatment Panel III (NCEP/ATP III) and the International Diabetes Federation (IDF) definitions in diagnosing MetS among Gaza Strip Palestinians. MATERIALS AND METHODS: This cross sectional study involved a randomly selected two hundred and thirty apparently healthy adults from the Gaza Strip. Anthropometric measurements, blood pressure, fasting plasma glucose, lipid profile, and questionnaire interviews were performed. RESULTS: The overall prevalence of MetS in our Gaza Strip cohort was 23.0% and 39.5% according to NCEP/ATP III and IDF definitions respectively (p<0.001). No significant differences were seen in the number of MetS components in individuals having MetS by either definition (mean 3.42 ± 0.63 vs 3.52 ± 0.69 respectively, p=0.865). Both IDF and NCEP/ATP III showed an increased prevalence of MetS with age, and body mass index (BMI), however they revealed different prevalence trends with sex. Except for BMI, there were no significant differences in the general and metabolic related characteristics between subjects with MetS of IDF and NCEP/ATP III definitions. CONCLUSIONS: Independently of the definition used, MetS is highly prevalent in Gaza Strip population, with a steady increase in MetS prevalence through age and BMI. The IDF definition tends to give higher values for MetS prevalence, and therefore could be more appropriate for diagnosing MetS in Gaza Strip cohort.

Prevalence of metabolic syndrome and associated socioeconomic and demographic factors among Palestinian adults (20-65 years) at the Gaza Strip.

OBJECTIVES: Metabolic syndrome (MetS) is a multifaceted syndrome and has been described as a clustering of several risk factors for cardiovascular disease. This study was conducted to estimate the prevalence of MetS and its individual components among Palestinian adults, 20-65 years old in Gaza Strip. In addition to find any possible associations with socioeconomic and demographic factors. MATERIAL AND METHODS: The study sample included 230 adults aged 20-65 years. Data were collected by questionnaire interviews, anthropometrics, and biochemical analysis that included: serum glucose, total cholesterol, triglyceride, HDL, and LDL. MetS was defined according to the NCEP/ATP III diagnostic criteria. RESULTS: Overall prevalence of MetS was 23.0% among the study subjects, with no significant differences between males (18.1%) and females (28.1%). The prevalence of MetS increased significantly with age and was associated significantly with physical activity and martial status, while no significant associations were found with household income; geographical locality; smoking; watching TV; or family history. CONCLUSIONS: Age, sex, physical activity and marital status are risk factors independently associated with MetS in the Palestinian population at the Gaza Strip. National health awareness and preventive programs should be established aiming at decreasing of MetS trends in the Palestinian population at Gaza Strip.

Normal blood cells reference intervals of healthy adults at the Gaza Strip-Palestine.

Hematological parameters are affected by different factors that include age, sex, smoking, ethnicity, and environmental altitude. It has been justified that each population must establish its own normal reference intervals to be used in clinical assessments and interpretations. Hematological reference intervals for adults from the Gaza Strip-Palestine have never been addressed. Therefore, this study was designed and aimed at the establishment of normal blood cells reference intervals for healthy adults at the Gaza Strip-Palestine. This study involved 89,491 apparently healthy individuals (from both sexes and from the different governorates of the Gaza Strip) who were referred to the Thalassemia Central Laboratory during the period from September 2000 until February 2008. Complete blood counts were performed. Subjects were categorized into subgroups according to gender, smoking habit, and age (15-18, 19-45, and >45 years old). For each subgroup, descriptive and comparative statistical analysis was performed for hematological parameters. The results showed substantial differences between males and females, between smokers and nonsmokers, and between the different age groups. Moreover, reference intervals derived from our population are markedly shifted downward as compared with Western European and American populations. It was concluded that separate and region-specific reference intervals based on gender, smoking, and age for the Palestinian population at the Gaza Strip should be generalized for clinical laboratories and clinical practitioners, which could help in interpreting laboratory hematological tests more specifically, and potentially develop the quality of medical care provided to patients.

Does cigarette smoking affect the diagnostic reliability of hemoglobin alpha 2 delta 2 (HbA2)?

Quantitation of hemoglobin alpha 2 delta 2 (HbA2) is a basic and confirmatory test in diagnosing the carrier state of beta-thalassemia. The present study was designed to investigate the effect of cigarette smoking on the diagnostic reliability of HbA2. A total of 2,867 (654 smokers and 2,213 never smokers) male subjects were involved in the present study. The subjects were categorized into three groups according to their laboratory findings: beta-thalassemia minor, iron deficient, and normal groups. Complete blood count (CBC) parameters and HbA2 levels were compared between smokers and never smokers of each group according to the independent-samples t-test using the SPSS program, significance results were reported at P<0.05. The results showed a significant increase in red blood cell (RBC) mass (RBC count and hematocrit [Hct]) and Hb concentration in smokers of all groups; however, no significant differences were reported in the HbA2 level between smokers and never smokers in all groups. It was concluded that cigarette smoking does not affect the diagnostic reliability of the HbA2 test.

Possible ameliorative effect of taurine in the treatment of iron-deficiency anaemia in female university students of Gaza, Palestine.

The aim of the study was to evaluate the haematological effects of adding the antioxidant taurine to iron sulfate in the treatment of iron-deficiency anaemia (IDA). A sample of 730 students from Al-Azhar University, Gaza, in Palestine underwent screening with complete blood counts and serum samples. In subjects with microcytosis/hypochromasia, Alpha2 delta2 (HbA2) and serum concentrations of iron, total iron binding capacity (TIBC), ferritin and taurine were determined. Samples from 17 normocytic, normochromic, and non-anaemic subjects were used as baseline controls. At base-line, 81 of the 730 subjects (11.1%) had microcytosis/hypochromasia, 26 (3.6%) were diagnosed as beta-thalassemia carriers, none of which was iron deficient. Four subjects had microcytosis of unknown cause. Fifty-one subjects (all females) had iron-deficiency anaemia and were included in the therapeutic study, which lasted for 20 wk. They were matched for Hb into pairs and were treated with oral iron (325 mg of slow-release iron sulfate). In addition, they were, in a double-blind procedure, randomised to additional oral taurine (1000 mg d(-1) at a cost comparable to that of adding ascorbic acid) or placebo. Mean S-taurine was significantly lower in the IDA subjects than in the controls. After 20 wk of iron supplementation, both the taurine and placebo group significantly improved their Hb concentrations and normalised the markers of iron deficiency. Apart from the expected, albeit in this study mild side-effects of oral iron, no significant side-effects were noted. In the taurine group, there was a statistically significant additive positive change from the baseline values on Hb (2.67 +/- 1.24 g dL(-1)), red blood cell (RBC) count [(0.57 +/- 0.25) x 1012 L(-1)] and serum ferritin (30.33 +/- 17.99 microg L(-1)) as compared to placebo group values, which were 1.80 +/- 1.10 g dL-1, (0.39 +/- 0.36) x 1012 L(-1), and 20.11 +/- 7.34 microg L(-1), respectively. Oral taurine appears to increase the effectiveness of oral iron in the treatment of IDA, and has no significant side-effects. This merits further cost-benefit and clinical analyses.