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PubMed2002

In vitro production and nuclear transfer affect dosage compensation of the X-linked gene transcripts G6PD, PGK, and Xist in preimplantation bovine embryos.

Equal expression of X-linked genes such as G6PD and PGK in females and males and the initiation of X-chromosome inactivation are critically dependent on the expression of the X-inactive specific transcript (Xist). The objective of the present study was to determine the effects of in vitro production (IVP) and nuclear transfer (NT) on the relative abundance (RA) of the X-linked transcripts G6PD, PGK, and Xist in preimplantation bovine embryos. In experiment 1, sex-determined IVP or in vivo-produced embryos were analyzed for mRNA expression of the 3 genes. The sex ratio was 36% vs. 64% in IVP blastocysts and thus deviated significantly from the expected ratio of 50% in the vivo control group. The RA of G6PD transcripts was significantly higher in female IVP embryos than in male embryos. In contrast, no significant differences were seen between in vivo-derived female embryos and their male counterparts. At the morula stage, female IVP embryos transcribed significantly more PGK mRNA than did male embryos. However, blastocysts did not exhibit significant differences in PGK transcripts. No differences were observed for in vivo-derived embryos with regard to the RA of PGK transcripts. The RA of Xist mRNA was significantly higher in all female embryos than in their male counterparts. In experiment 2, IVP, in vivo-developed, NT-derived, and parthenogenetic embryos carrying two X chromosomes of either maternal and paternal origin or of maternal origin only (parthenogenotes) were analyzed for the RA of the 3 genes. In NT-derived morulae, the RA of G6PD transcripts was significantly increased compared with their IVP and in vivo-generated counterparts. G6PD transcript levels were significantly increased in IVP blastocysts compared with in vivo-generated and parthenogenetic embryos. At the morula stage, PGK transcripts were similar in all groups, but the RA of PGK transcripts was significantly higher in IVP blastocysts than in their in vivo-generated, parthenogenetic, and NT-derived counterparts. The RA of Xist was significantly elevated in NT-derived morulae compared with IVP, in vivo-generated, and parthenogenetic embryos. NT-derived blastocysts showed an increased Xist expression compared with that of IVP, in vivo-generated, and parthenogenetic embryos. Results of the present study show for the first time that differences in X-chromosome-linked gene transcript levels are related to a perturbed dosage compensation in female and male IVP and female NT-derived embryos. This finding warrants further studies to improve IVP systems and NT protocols to ensure the production of embryos with normal gene expression patterns.

Animals↗
PubMed2005

Diagnosis of red cell G6PD deficiency in rural Burkina Faso: comparison of a rapid fluorescent enzyme test on filter paper with polymerase chain reaction based genotyping.

Glucose-6-phosphate dehydrogenase (G6PD) deficient individuals are at increased risk of developing haemolysis following treatment with various antimalarial drugs. Reliable field tests for G6PD deficiency are thus needed in chemotherapy studies and their validity has to be assessed. In two phase II clinical trials on methylene blue (MB) antimalarial therapy in rural Burkina Faso, paediatric and adult participants were tested for G6PD deficiency. The results of a haemoglobin-adjusted nicotinamide adenine dinucleotide phosphate (NADPH) fluorescence test on paper (NFP test) were compared with polymerase chain reaction (PCR)-based G6PD genotyping also using blood samples on filter papers. This is the first study comparing sensitivity and specificity of the two methods. There was good agreement between the NFP test results and the PCR findings. The estimate of the sensitivity of the NFP test was 98.2% (95.8-99.6%) and the specificity was 97.1% (94.2-99.2%). In conclusion, the NFP assay is a reliable and inexpensive method for large-scale G6PD deficiency screening in rural West Africa.

Adolescent↗
PubMed1989

Different polymorphic variants of glucose-6-phosphate dehydrogenase (G6PD) in Italy.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is common in Italy and recent biochemical and kinetic studies have demonstrated the presence of polymorphic variants associated with severe or mild enzyme deficiency. We performed a biochemical characterization of G6PD in a large number of Italian G6PD deficient men in an attempt to identify the most reliable biochemical indices for discriminating polymorphic G6PD variants and to define their distribution throughout the country. Three polymorphic G6PD variants, respectively named Mediterranean, Cagliari and Sassari, were identified. The elution profile on DEAE-Sephadex column chromatography, substrate analogue utilization and the Michaelis constant for G6P were the most significant parameters to discriminate polymorphic variants among the variants with activity levels lower than 0.8 IU/g Hb. The distribution of the polymorphic variants, in relation to the origin of the subjects studied, differs throughout the country.

Chromatography, Ion Exchange↗
PubMed2002

Glucose-6-phosphate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima: expression of the g6pd gene and characterization of an extremely thermophilic enzyme.

The gene (open reading frame Tm1155, g6pd) encoding glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) of the hyperthermophilic bacterium Thermotoga maritima was cloned and functionally expressed in Escherichia coli. The purified recombinant enzyme is a homodimer with an apparent molecular mass of 95 kDa composed of 60-kDa subunits. Rate dependence (at 80 degrees C) on glucose-6-phosphate and NADP(+) followed Michaelis-Menten kinetics with apparent K(m) values of 0.15 mM and 0.03 mM, respectively; apparent V(max) values were about 20 U mg(-1). The enzyme also reduced NAD(+) (apparent K(m) 12 mM, V(max) 12 U mg(-1)). The 1000-fold higher catalytic activity (k(cat)/K(m)) with NADP(+) over NAD(+) defines the G6PD as NADP(+) specific in vivo. G6PD activity was competitively inhibited by NADPH with a K(i) value of 0.11 mM. With a temperature optimum of 92 degrees C the enzyme is the most thermoactive G6PD described.

Cloning, Molecular↗
PubMed1987

Does G6PD deficiency protect against cancer? A critical review.

Previous observations on the lower mortality for cancer experienced in populations with a higher frequency of G6PD deficiency support biochemical studies on the role of G6PD during cell proliferation. The general agreement among experimental studies prevented a deeper analysis of the sources of what has been called "epidemiological evidence of the protective role of G6PD deficiency against cancer". This review analyses the methods and findings in those papers, stressing their limitations and emphasising that no final conclusions can be drawn from them. Preliminary results of ongoing epidemiological studies of G6PD deficiency and cancer are presented, although they do not prove or disprove the hypothesis that G6PD deficiency protects against cancer.

Anthropometry↗
PubMed1999

Detection of the most common G6PD gene mutations in Chinese using amplification refractory mutation system.

Glucose-6-phosphate dehydrogenase (G6PD) is the most common human enzymopathy. To date more than 122 mutations in the G6PD gene have been discovered, among which 12 point mutations are found in the Chinese. The 2 most common mutations, G1388A and G1376T, account for more than 50% of mutations representing various regions and ethnic groups in China. Setting up a simple and accurate method for detecting these mutations is not only useful for studying the frequency of the G6PD genotypes, but also for finding new mutations. The purpose of this study was to find a simple, inexpensive and accurate method for detecting these common mutations. The amplification refractory mutation system (ARMS) method was used in this study. Samples from 28 G6PD-deficient males were investigated. The natural and mismatched amplification and restriction enzyme digestion method was used as a standard method to evaluate the nature of the point mutations. Sixteen cases were found carrying the G1388A mutation and 12 the G1376T mutation. Fourteen cases of G1388A and 10 cases of G1376T were confirmed by ARMS. Four cases were not in concordance with the results obtained by the mismatched amplification-restriction enzyme digestion. These 4 cases were then judged by direct PCR sequencing at exon 12. The DNA sequencing data supported the results obtained by ARMS. Thus we concluded that the ARMS is a rapid, simple, inexpensive and accurate method for detecting the most common G6PD gene mutations among the Chinese.

Asian People↗
PubMed1988

Subchromosomal localization and order of GLA, PGK1, HPRT, and G6PD loci on the X chromosome of the American mink (Mustela vison).

Segregation of the X-linked mink markers alpha-galactosidase (GLA), phosphoglycerate kinase-1 (PGK1), hypoxanthine phosphoribosyltransferase (HPRT), and glucose-6-phosphate dehydrogenase (G6PD) was analyzed in hybrids of gamma-irradiated mink fibroblasts and Chinese hamster cells and in hybrids of nonirradiated mink fibroblasts and mouse hepatoma cells. Based on this analysis, the order of the four genes is GLA-PGK1-HPRT-G6PD on the mink X chromosome. Cytogenetic analysis of five mink x Chinese hamster hybrid clones containing mink GLA, PGK1, and HPRT, but lacking G6PD, tentatively localized mink G6PD to Xq15.22----qter and also confirmed the gene order as GLA-PGK1-HPRT-G6PD-qter. Comparison of this order with its counterpart in man and the mouse, as well as an analysis of the G-band patterns of their X chromosomes, demonstrated putative similarities between mink and man and differences in the mouse. These differences may be due to a different rate of X-chromosomal rearrangement in mammalian evolution.

Animals↗
PubMed1982

G6PD in immature and mature human brain. Electrophoretic and enzyme kinetic studies.

The isoenzyme polymorphism and kinetics of glucose-6-phosphate dehydrogenase (G6PD) in embryonal and mature brain were studied. Two types of electropherograms were found in embryonal brains: type I is characterized by two G6PD fractions: slow and fast, and in the type II a single, fast-moving G6PD fraction was seen in a single embryo. The additional studies carried out, namely reelectrophoresis following 2-mercaptoethanol and NADP treatment and the specific enzyme kinetics, i.e. altered Michaelis constant and enhanced utilization of the desamino-NADP analogue which are typical of the fast-moving fraction in embryonal brain, speak unequivocally in favor of the presence of a new, unknown, phase-specific isoenzyme of G6PD. Its synthesis takes place only during embryonal brain development. A probable autosomal localization for the gene of brain G6PD is suggested.

Brain↗
PubMed1985

G6PD encapsulation and metabolic properties of loaded erythrocytes.

Two different dialysis methods were used to G6PD load the erythrocytes of G6PD deficient subjects. With both methods the yield of entrapment was about 30-40% of the added G6PD. The functional behaviour of these G6PD loaded erythrocytes was evaluated by HMS either in resting conditions or under oxidative stimulation. An increase of the metabolic activity of the G6PD loaded erythrocytes was found. This model provides an useful approach in studying the hemolytic activity of a variety of agents.

Erythrocytes↗
PubMed1999

Hemolytic crisis after excessive ingestion of fava beans in a male infant with G6PD Canton.

After ingesting fava beans, a 26-month-old Chinese-Japanese male infant showed a sickly complexion and yellowish-brownish skin and was hospitalized. Severe hemolytic anemia was observed on admission, and transfusion of 200 ml of packed red cells was required. Red cell enzyme assay revealed that the patient and the mother were deficient in glucose-6-phosphate dehydrogenase (G6PD). Subsequent molecular analysis showed that the patient had a missense mutation 1376 G to T (G6PD Canton) and his mother was a homozygote for the mutation. The patient was a son of a Chinese (Taiwanese) mother and a Japanese father. Although G6PD deficiency is rare in the original Japanese population, the number of "imported" cases could be rising rapidly. This is the first reported Japanese case of G6PD deficiency with G6PD Canton.

Amino Acid Sequence↗
PubMed2000

1376G-->T mutation of G6PD gene in Han and Li nationalities in Hainan, China.

OBJECTIVE: To investigate the 1376G-->T mutation of G6PD gene in the cases of G6PD deficiency in the Han nationality and the Li nationality of Hainan, China. METHODS: DNAs were extracted from the white blood cells of G6PD deficient cases by salt-out method. Allelic specific polymerase chain reaction was used to detect the 1376G-->T mutation. RESULTS: Fifty-nine Han nationality cases and 32 Li nationality cases were analysed; the 1376G-->T mutation was found in 19 Han cases(32.2%) and 18 Li cases(56.2%). CONCLUSION: 1376G-->T is a common mutation which causes G6PD deficiency in the Han nationality and the Li nationality in Hainan, China. Based on the phylogenetic tree of populations in China, these results indicate that the mutation might occur prior to the divergence of the Han and Li nationalities. It is of significance to study the mutations of G6PD gene in different nationalities in China for elucidating the origin, migration and evolution of the nationalities.

Biological Evolution↗
PubMed2000

[Comparative study of three common G6PD gene mutations in Yao and Han People in Guangxi].

OBJECTIVE: To study G6PD gene mutation diversity in Yao and Han people in Guangxi and compare the genotypic frequencies. METHODS: The three common G6PD gene mutations in Chinese were investigated in 34 G6PD deficient individuals from Yao and 37 from Han people by using an amplification refractory mutation system (ARMS). RESULTS: Among 34 cases of G6PD deficiency of Yao people, the genotypic frequencies of G1376T, G1388A and A95G were 41.2%, 26.5% and 14.7%, respectively. A case of C1311T was detected. As compared with that in Han people, the respective frequencies were 16.2%, 40.6% and 5.4%. CONCLUSION: The main G6PD mutations in Yao people were the same with Han people in Guangxi, but G1376T mutation was higher than that in Han people. The C1311T mutation in Yao people in Guangxi was reported for the first time.

Adolescent↗
PubMed1997

[Identification of G6PD gene mutations in several nationalities from Yunnan province].

OBJECTIVE: To analyze the G6PD gene mutations in several nationalities from Yunnan province. METHODS: G6PD gene mutation of 29 samples from G6PD deficient patients were analyzed by using common and mis-matched primering PCR followed by restriction enzyme digestion. The samples were collected from Yunnan province among several nationalities. RESULTS: In these 29 cases, 20 were of two known mutations, including 19 of 1388 (G-->A) and 1 of 1376 (G-->T) mutation. The 7 cases of national minorities, including 3 of Yi ([symbol: see text]), 2 of Bai ([symbol: see text]), 1 of Dai ([symbol: see text]), and 1 of Naxi ([symbol: see text]), were all 1388 mutations. No report of the G6PD gene 1388 mutation in these ethnic groups was published excepting for Dai. CONCLUSION: The mutation probably had been prevalent before the emergence of these national minorities. The approximate rate of G6PD gene mutations provided in Yunnan province may, in some respects, help to interpret the molecular evolution.

Asian People↗
PubMed2003

[Glucose-6-phosphate dehydrogenase (G6PD) deficiency--a cause of anaemia in pregnant women].

Glucose-6-phosphate dehydrogenase (G6PD) is one of the most important cytoprotective enzymes for oxidative stress. The WHO classification of G6PD deficiency, based on enzyme activity and clinical significance, distinguishes five variants. Chronic haemolytic process is rare and the main factors causing haemolysis are: infections, substances derived from plants, drugs with high oxidation-reduction potential, stress, ketoacidosis in diabetes and surgery operations. We report two cases of women belonging to the class 3 of the WHO classification in whom haemolysis occured during pregnancy. One of the patients developed two incidents of haemolytic anaemia. The cause of the first episode, nine months before pregnancy, was probably infection of the urinary tract caused by Escherichia coli, but the influence of the drugs also cannot be excluded. Because of the genetic background of this enzymopathy we also examined members of the patients, families but did not find any evidence of G6PD deficiency among them. The reported cases indicate that haemolytic anaemia caused by G6PD deficiency may occur during pregnancy what can lead to many not only haematological but also serious obstetrical complications such as infertility, fetus malformations and even its death. We also draw attention to several difficulties in diagnosing G6PD deficiency especially during haemolysis.

Adult↗
PubMed1991

Glucose-6-phosphate dehydrogenase (G6PD) deficiency in southern Italy: a study on the population of the Cosenza province.

35,660 healthy children attending secondary school in the Cosenza province, in the North of Calabria (Southern Italy), were screened for G6PD deficiency. Of 16,787 schoolboys, 209 were found to be G6PD deficient (1.24%). Of these, 99 (47.37%) had red cell G6PD activity below 5%, and they were classified as having the G6PD Mediterranean phenotype. The remaining 110 (52.63%), had a mild to moderate degree of deficiency, with an enzyme activity between 5 and 60%. Of these, 82 (74.55%) were electrophoretically normal, while 17 (15.45%) were electrophoretically fast and 11 (10.0%) were electrophoretically slow. The highest incidence of G6PD deficiency is on the Ionian Coast and along the Crati and Esaro river valleys, in good agreement with the distribution of the past malarial endemicity.

Adolescent↗
PubMed1991

Characterization of erythrocytic glucose-6-phosphate dehydrogenase in a mouse strain with reduced G6PD activity.

Erythrocytic glucose-6-phosphate dehydrogenase (G6PD) of a mutant mouse strain with X-linked G6PD-deficiency was purified and compared with the wildtype G6PD by biochemical and physiological characteristics. The red cell G6PD activity of the mutant was 20% of the wildtype. The Michaelis constant (Km) of the substrate glucose-6-phosphate (G6P) was higher (90 microM) for the mutant than for the wildtype (56 microM). The isoelectric focusing with a pH range from 3 to 10 showed one more enzymatically active band for the wildtype G6PD compared to the mutant enzyme. Other enzyme characteristics, however, such as Km for nicotinamide adenine dinucleotide phosphate (NADP), utilisation of 2-deoxy-glucose-6-phosphate (2dG6P) and deamino-NADP, heat stability, pH optimum, molecular weight, and glucose metabolisation via the pentosephosphate pathway were similar in mutant and wildtype enzyme.

Animals↗
PubMed1983

Structural variants of human glucose 6-phosphate dehydrogenase (G6PD): role of intracellular decay in the expression of deficiency.

The biochemical mechanisms of enzyme deficiency were investigated for two low activity G6PD variants, i.e. G6PD Mediterranean and G6PD Cagliari (a new variant). This study required the complete removal of leukocytes and platelets from blood samples and the use of sensitized procedures for assays of activity. G6PD Cagliari has a highly accelerated decay within circulating RBC and a near normal catalytic efficiency. The deficiency typical of G6PD Mediterranean (approx. 0.1% of the normal levels) is mediated by moderately reduced specific activity, while no clear decay was seen in mature RBC: however, the minute levels of activity that are observed in reticulocytes suggest that a strongly enhanced breakdown takes place during maturation of erythroid cells.

Erythrocyte Aging↗
PubMed1994

The use of primaquine in malaria infected patients with red cell glucose-6-phosphate dehydrogenase (G6PD) deficiency in Myanmar.

32 subjects with Plasmodium falciparum gametocytes, and 31 cases with Plasmodium vivax infection from two military hospitals (Lashio, Mandalay) were treated with quinine 600 mg three times a day for 7 days followed by primaquine 45 mg single dose for gametocytes and 45 mg weekly x 8 weeks for vivax malaria. Although screening of red cell glucose-6-phosphate dehydrogenase (G6PD) was done prior to primaquine treatment, G6PD deficient subjects were not excluded from the trial. 20 patients hemizygous for mild G6PD deficiency (GdB- variant), 2 patients hemizygous for severe deficiency (Gd-Myanmar variant) completed the trial. No case of acute hemolysis was observed in all 22 patients with two genotypes of red cell G6PD deficiency status. Therefore, a single dose of primaquine 45 mg and/or weekly for 8 weeks is adequate for the treatment of patients with P. falciparum gametocytes and/or P. vivax malaria ignoring these red cell G6PD enzyme deficient variants in Myanmar.

Developing Countries↗