Molecular characterization of G6PD mutations reveals the high frequency of G6PD Aures in the Lao Theung population.

BACKGROUND: The prevalence and genotypes of G6PD deficiency vary worldwide, with higher prevalence in malaria endemic areas. The first-time assessment of G6PD deficiency prevalence and molecular characterization of G6PD mutations in the Lao Theung population were performed in this study. METHODS: A total of 252 unrelated Lao Theung participants residing in the Lao People's Democratic Republic (PDR) were recruited. All participant samples were tested for G6PD enzyme activity and G6PD gene mutations. The amplification refractory mutation system (ARMS)-PCR for detecting G6PD Aures was developed. RESULTS: The G6PD mutations were detected in 11.51% (29/252) of the participants. Eight G6PD mutations were detected. The G6PD Aures was the most common mutation identified in this cohort, which represented 58.62% (17/29) of all mutation. The mutation pattern was homogenous, predominantly involving the G6PD Aures mutation (6.75%), followed by 1.19% G6PD Union and 0.79% each G6PD Jammu, G6PD Mahidol and G6PD Kaiping. One subject (0.4%) each carried G6PD Viangchan and G6PD Canton. Interestingly, one case of coinheritance of G6PD Aures and Quing Yan was detected in this cohort. Based on levels of G6PD enzyme activity, the prevalence of G6PD deficiency in the Lao Theung population was 9.13% (23/252). The prevalence of G6PD deficient males and females (activity < 30%) in the Lao Theung population was 6.41% (5/78) and 1.72% (3/174), respectively, and the prevalence of G6PD intermediate (activity 30-70%) was 5.95% (15/252). CONCLUSIONS: The G6PD Aures mutation is highly prevalent in the Lao Theung ethnic group. The common G6PD variants in continental Southeast Asian populations, G6PD Viangchan, Canton, Kaiping, Union and Mahidol, were not prevalent in this ethnic group. The technical simplicity of the developed ARMS-PCR will facilitate the final diagnosis of the G6PD Aures.

Impact of glucose-6-phosphate dehydrogenase deficiency on sickle cell anaemia expression in infancy and early childhood: a prospective study.

In patients with sickle cell anaemia (SCA), concomitant glucose-6-phosphate dehydrogenase (G6PD) deficiency is usually described as having no effect and only occasionally as increasing severity. We analysed sequential clinical and biological data for the first 42 months of life in SCA patients diagnosed by neonatal screening, including 27 G6PD-deficient patients, who were matched on sex, age and parents' geographic origin to 81 randomly selected patients with normal G6PD activity. In the G6PD-deficient group, steady-state haemoglobin was lower (-6·2 g/l, 95% confidence interval (CI), [-10·1; -2·3]) and reticulocyte count higher (247 × 10(9) /l, 95%CI, [97; 397]). The acute anaemic event rate was 3 times higher in the G6PD-deficient group (P < 10(-3) ). A higher proportion of G6PD-deficient patients required blood transfusion (20/27 [74%] vs. 37/81 [46%], P < 10(-3) ), for acute anaemic events, and also vaso-occlusive and infectious events. No significant between-group differences were found regarding the rates of vaso-occlusive, infectious, or cerebrovascular events. G6PD deficiency in babies with SCA worsens anaemia and increases blood transfusion requirements in the first years of life. These effects decrease after 2 years of age, presumably as the decline in fetal haemoglobin levels leads to increased sickle cell haemolysis and younger red blood cells with higher G6PD activity.

Hypercalcemia in glycogen storage disease type I patients of Turkish origin.

Glycogen storage disease type I (GSD I) is an autosomal recessive disorder caused by defects in the glucose-6-phosphatase complex. Deficient activity in the glucose-6-phosphatase-a (G6Pase) catalytic unit characterizes GSD IA and defects in the glucose-6-phosphate transporter protein (G6PC) characterize GSD IB. The main clinical characteristics involve fasting hypoglycemia, hyperuricemia, hyperlactatemia, and hyperlipidemia. Hypercalcemia arose as an unknown problem in GSD I patients, especially in those with insufficient metabolic control. The aim of the present study was to obtain the prevalence of hypercalcemia and to draw attention to the metabolic complications of GSD I patients, including hypercalcemia in poor metabolic control. Hypercalcemia frequency and the affecting factors were studied cross-sectionally in 23 GSD I pediatric subjects. Clinical diagnosis of GSD I was confirmed in all patients either through documentation of deficient G6Pase enzyme activity levels on liver biopsy samples or through G6PC gene sequencing of DNA. Hypercalcemia was detected in 78.3% of patients with GSD I. Different from the previous report about hypercalcemia in a GSD IA patient who had R83H and 341delG mutations, we could not identify any genotype-phenotype correlation in our GSD I patients. Hyperlactatemia and hypertriglyceridemia correlated significantly with hypercalcemia. Furthermore, no differences in serum calcium concentrations could be demonstrated between patients with optimal metabolic control. We observed hypercalcemia in our series of GSD I patients during acute metabolic decompensation. Therefore, we speculate that hypercalcemia should be considered as one of the problems of GSD I patients during acute attacks. It may be related with prolonged lactic acidosis or may be a pseudohypercalcemia due to hyperlipidemia that can be seen in GSD I patients with poor metabolic control.

Large scale screening for haemoglobin disorders in southern Vietnam: implications for avoidance and management.

In order to obtain an approximate assessment of the public health burden that will be posed by the inherited disorders of haemoglobin in southern Vietnam, several thousand individuals were screened for these conditions. A smaller sample was screened for glucose-6-phosphate dehydrogenase (G6PD) deficiency. The important haemoglobin disorders identified were beta thalassaemia, haemoglobin E and a variety of different forms of alpha thalassaemia. There were sufficient G6PD-deficient individuals to materially affect malaria control programme design. The most remarkable finding was wide variation in the gene frequencies of these conditions among the ethnic groups sampled. The approximate number of babies expected to be born with clinically significant haemoglobin disorders in Vietnam was estimated from the gene-frequency data. This study emphasizes the importance of wide-scale population screening, including ethnic subgroups, to establish the requirements for inherited haemoglobin disorder programmes in resource-limited settings.

Screening for glucose-6-phosphate dehydrogenase deficiency in blood donors.

AIM: Our purpose was to determine the frequency of glucose-6-phosphate dehydrogenase (G6PD) deficiency in blood donors of Jahrom, Iran. METHODS: Blood samples were obtained from the 706 blood donors who referred to Jahrom Blood Transfusion Organization between June and September 2008. Enzyme assays were performed three times, on day 1 (day of blood sampling), 7 and 45 days after blood storage. G6PD activity was measured using a quantitative assay. RESULTS: A total of 706 samples were examined. 97.7% males and 2.3% females, mean age 32.6 years (18-64 years). Based on enzyme activity less than 1.62 IU/g hemoglobin (Hb), prevalence of G6PD deficiency in three separate measurements was 16.3, 19.1 and 33.3% respectively. Four percent of donor had an enzyme level of zero on day 1 which increased to 7.4 and 10.7% on the seventh and the forty-fifth days. CONCLUSION: The results of this study support the screening for G6PD as part of the routine workup of blood donors in areas with a high prevalence of G6PD deficiency.

The first case of a class I glucose-6-phosphate dehydrogenase deficiency, G6PD Santiago de Cuba (1339 G > A), in a Chinese population as found in a survey for G6PD deficiency in northeastern and central China.

In Liaoning Province in northeastern China, we found a G6PD-deficient patient at the age of 3. By the classification of the World Health Organization, this patient was categorized as class I (very severe G6PD deficiency). When we investigated the G6PD gene of the patient, we found that he had a replacement of G to A at nucleotide 1339. As a result, the amino acid at position 447 should change from Gly to Arg. This replacement is known as G6PD Santiago de Cuba, because it was first discovered in a Cuban boy who showed heavy chronic anemia. Today, 28 G6PD variants have been reported in the Chinese population, and all are categorized as class II (severe deficiency) or class III (mild deficiency); in class II or III deficiency, anemia is not present in daily life, but hemolytic attack can occur when the carrier ingests certain oxidative medicines or foods. This is the first report of a G6PD-deficient Chinese patient in the category of class I. We intended to find other G6PD-deficient cases in northeastern China and tested several hundred blood samples, but no cases of G6PD deficiency were found (0/414). In central China, where falciparum malaria was endemic from the 1950s to 1970s, we found two G6PD-deficient cases (2/27) and the other members from their families whose variant type was G6PD Kaiping (1388G > T), which is a common variant in the Chinese population.

Hematological profile of twenty-nine tribal compound cases of hemoglobinopathies and G-6-PD deficiency in rural Orissa.

BACKGROUND: Hematogenetic disorders are commonly encountered in Orissa state in Central-Eastern India. Hemoglobinopathies and G-6-PD deficiency are the most frequently occurring hereditary hemolytic disorders causing high morbidity and mortality in vulnerable people. AIMS: There is no study available reporting combined condition of hemoglobinopathies and G-6-PD deficiency in a single individual from India. This study aims to assess the coincidence of G-6-PD enzyme deficiency with different hemoglobinopathies and beta-thalassemia and to evaluate the influence of combined conditions on the hematological expression. SETTINGS AND DESIGN: The study was carried out in rural Orissa with a random sampling procedure. MATERIALS AND METHODS: Following the standard methodology and techniques, this study highlights 29 tribal cases of compound occurrence of hemoglobinopathy with G-6-PD deficiency in a randomly conducted study in Sundargarh district of Orissa. STATISTICAL ANALYSIS: Results were subjected to statistical analysis. RESULTS: Both female heterozygotes and homozygotes of G-6-PD deficiency in association with different hemoglobinopathies showed reduced values of hematological indices: hemoglobin level, MCV, MCH, MCHC and RBC in comparison to normals. Red cell indices were found further reduced in male G-6-PD deficiency concurrence with hemoglobinopathies in homozygous condition, i.e. sickle cell disease (HbSS) or hemoglobin E disease (HbEE). Hematological indices were significantly lower except WBC counts and fetal hemoglobin in male G-6-PD deficiency with co-existing homozygous sickle cell disease in comparison with counterpart sickle cell trait and normal controls. CONCLUSIONS: Hemoglobin polymorphism with G-6-PD deficiency is advantageous to the community against lethal effects of malaria especially against Plasmodium falciparum at population level, but their combination is harmful at the individual level because of low levels of red cell indices to cope with the routine human physiology.

Prevalence and significance of G6PD deficiency in patients of an urban HIV clinic.

The rationale to screen for glucose-6-phosphate dehydrogenase (G6PD) deficiency in HIV-infected individuals is their increased likelihood to receive oxidant drugs and subsequent potential of hemolytic events. However, current guidelines regarding who should be screened are conflicting. The authors examined the prevalence of G6PD deficiency and the frequency of hemolytic events in an urban HIV clinic. They used data from a military database as a comparison. In both cohorts, a relatively high number of black females were found to be G6PD deficient (10% and 13%), which was similar to the rate in men (15% and 12%). No white females were G6PD deficient. The authors identified 8 drug-related hemolytic events in HIV clinic patients. Two patients necessitated blood transfusions; both were triggered by trimethoprim/sulfamethoxazole (TMP/SMX). Although G6PD screening prior to the use of TMP/SMX is not often considered by clinicians, the authors' finding of 2 hemolytic events requiring transfusion suggests this would be beneficial.

[A young man with acute generalised jaundice and intermittent epigastric pain]. / Plötzlicher Ikterus mit Oberbauchschmerzen bei einem jungen Mann.

HISTORY: A 24-year-old Iraqi was admitted to our hospital with acute generalised jaundice and intermittent epigastric pain. His family doctor suspected a viral hepatitis. Two days prior admission the patient had consumed large quantities of alcohol and had subsequently taken analgetic dosages of paracetamol and acetylsalicylic acid. INVESTIGATIONS: Besides an otherwise inconspicuous physical examination the laboratory results revealed a distinct hemolysis with macrocytic, hyperchromic anaemia and negative Coombs-test. Indirect bilirubin was initially 25.2 mg/dl, LDH 2367 U/l and reticulocytes 4.4 %; haptoglobin and transferrine levels were correspondingly low. A hemoglobinopathies was excluded by hemoglobin-electrophoresis and a blood-smear. DIAGNOSIS, TREATMENT AND FURTHER COURSE: A glucose-6-phosphate dehydrogenase deficiency (G6PDD) was suspected and subsequently confirmed within three days. Acetylsalicylic acid, the most probable trigger, and other possible triggers like ciprofloxacin, metamizole, and cotrimoxazole were avoided; the jaundice faded rapidly, and the laboratory-parameters almost normalized. CONCLUSION: In patients with acute jaundice, abdominal pain, and signs of hemolysis collection of accurate anamnestic information is essential. In case of a young male with positive family-history, applicable ethnical origin, and intake of potential oxidative stressors a G6PDD should be suspected and result in requesting specific tests. Analgetic therapy with metamizole must be strictly avoided.

Mutation frequencies for glycogen storage disease Ia in the Ashkenazi Jewish population.

Glycogen storage disease type Ia (GSDIa) is a severe autosomal recessive disorder caused by deficiency of the enzyme D-glucose-6-phosphatase (G6Pase). While numerous mutations have been found in cosmopolitan European populations, Ashkenazi Jewish (AJ) patients appear to primarily carry the R83C mutation, but possibly also the Q347X mutation found generally in Caucasians. To determine the frequency for both these mutations in the AJ population, we tested 20,719 AJ subjects for the R83C mutation and 4,290 subjects for the Q347X mutation. We also evaluated the mutation status of 30 AJ GSDIa affected subjects. From the carrier screening, we found 290 subjects with R83C, for a carrier frequency for this mutation of 1.4%. This carrier frequency translates into a predicted disease prevalence of 1 in 20,000, five times higher than for the general Caucasian population, confirming a founder effect and elevated frequency of GSDIa in the AJ population. We observed no carriers of the Q347X mutation. Among the 30 GSDIa affected AJ subjects, all were homozygous for R83C. These results indicate that R83C is the only prevalent mutation for GSDIa in the Ashkenazi population.

Molecular genetics of glycogen-storage disease type 1a in Chinese patients of Taiwan.

The mutation spectrum of the glucose 6-phosphatase (G6Pase) gene in Chinese patients with type 1a glycogen-storage disease of Taiwan was studied by PCR/RFLP, temporal temperature gradient gel electrophoresis, and direct DNA sequencing methods. In addition to the two most prevalent mutations, 727G --> T (44.4%) and R83H (36.1%), that were detected by RFLP analysis, five other mutations, 341delG, 933insAA, Q104X, I341N, and H119L were identified. The frameshift mutations (341delG and 933insAA) and the nonsense mutation (Q104X) that produce truncated proteins are predicted to be disease-causing. The missense mutation, I341N, occurring in the last transmembrane domain of the ER-bound enzyme, retains a small amount of residual activity of approximately 10%. Except for R83H, the mutations have been described only in Asians. H119L, however, is of particular interest because of the essential role of the catalytic histidine of phosphohydrolase. This amino acid is believed to be involved in the formation of the phosphoryl-enzyme intermediate during catalysis. The patient who was compound heterozygous for 727G --> T and H119L mutations had essentially no G6Pase activity in her liver biopsy. This observation is consistent with the importance of H119L in catalysis.

Molecular genetic analysis of 40 patients with glycogen storage disease type Ia: 100% mutation detection rate and 5 novel mutations.

Molecular genetic analysis of 40 patients with glycogen storage disease type Ia (GSD Ia) revealed mutations on all 80 alleles and verified the diagnosis in all patients. At least 7 patients were diagnosed with GSD Ia solely on the basis of clinical findings prior to our analysis. Five mutations, Q20R, W50X, G81R, W156L, and G188D have not been reported so far. This study underscores that molecular genetic analysis is a reliable and convenient alternative to the enzyme assay in a fresh liver biopsy specimen to diagnose GSD Ia.

Glucose-6-phosphatase gene (727G-->T) splicing mutation is prevalent in Hong Kong Chinese patients with glycogen storage disease type 1a.

Glycogen storage disease type la (GSD1a) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (G6Pase). We analyzed the G6Pase genes of two unrelated Chinese families with GSD1a. DNA sequencing of all five exons and the exon-intron boundaries revealed a G T transversion at nucleotide 727 (727G-->T) in exon 5, which has previously been reported to cause abnormal splicing. In one family, the subject and her affected sister were confirmed to be homozygous for this mutation and their parents to be heterozygotes. In the other family, the proband was identified to be heterozygous for this mutation, and a novel mutation, the 341delG in exon 2, was identified. This mutation alters the reading frame and creates a stop codon TAA 15 codons downstream from the mutation, resulting in a truncated protein. Family studies revealed that the father was heterozygous for the 727G-->T mutation and that the mother was heterozygous for the 341delG mutation. This is the first time that the 727G T mutation has been found in Chinese patients or outside Japan. Since we only tested two GSD1a families and found 727G-->T in both, we believe that this mutation may also be prevalent in our local Chinese population. To investigate allele frequencies, we screened 385 Chinese healthy volunteers and found two asymptomatic carriers. Our findings suggest that the 727G-->T mutation is indeed prevalent in Hong Kong.

Glycogen storage disease type 1a in Israel: biochemical, clinical, and mutational studies.

Glycogen storage disease type 1a (von Gierke disease, GSD 1a) is caused by the deficiency of microsomal glucose-6-phosphatase (G6Pase) activity which catalyzes the final common step of glycogenolysis and gluconeogenesis. The recent cloning of the G6Pase cDNA and characterization of the human G6Pase gene enabled the characterization of the mutations causing GSD 1a. This, in turn, allows the introduction of a noninvasive DNA-based diagnosis that provides reliable carrier testing and prenatal diagnosis. In this study, we report the biochemical and clinical characteristics as well as mutational analyses of 12 Israeli GSD 1a patients of different families, who represent most GSD 1a patients in Israel. The mutations, G6Pase activity, and glycogen content of 7 of these patients were reported previously. The biochemical data and clinical findings of all patients were similar and compatible with those described in other reports. All 9 Jewish patients, as well as one Muslim Arab patient, presented the R83C mutation. Two Muslim Arab patients had the V166G mutation which was not found in other patients' populations. The V166G mutation, which was introduced into the G6Pase cDNA by site-directed mutagenesis following transient expression in COS-1 cells, was shown to cause complete inactivation of the G6Pase. The characterization of all GSD 1a mutations in the Israeli population lends itself to carrier testing in these families as well as to prenatal diagnosis, which was carried out in 2 families. Since all Ashkenzai Jewish patients harbor the same mutation, our study suggests that DNA-based diagnosis may be used as an initial diagnostic step in Ashkenazi Jews suspected of having GSD 1a, thereby avoiding liver biopsy.