Molecular Characterization of G6PD Deficient Variants in Nineveh Province,Northwestern Iraq

Glucose-6-phosphate dehydrogenase (G6PD) deficiency considered to be the commonest inherited enzymopathies disorders worldwide including Iraq. Studies have addressed its prevalence and molecular characterization in several parts of the country, but no data were available from Nineveh province, northwestern-Iraq regarding molecular basis of this inherited enzymopathy. To determine the molecular basis of G6PD deficient variants in Nineveh province. A total of 61 G6PD deficient male individuals from Nineveh province were enrolled in this study. DNA from all enrolled individuals were extracted and analyzed for four deficient molecular variants using a polymerase chain reaction–restriction fragment polymorphism method. These deficient variants were G6PD-Mediterranean (563 C→T), G6PD-Chatham (1003 G→A), G6PD-A-(202 G→A) and G6PD-Cosenza (1376 G→C). Also enrolled individuals were screened for silent 1311 (C→T) mutation. It was found that 46 (75.41 %) were G6PD-Mediterranean, 1(1.64 %) were G6PD-Chatham, another 1(1.64 %) were G6PD-A-, and 13 (21.31 %) were remained uncharacterized. Also all G6PD-Mediterranean as well as one uncharacterized individuals were carriers of silent 1311 (C→T) mutation. This study documented that G6PD-Mediterranean constitute the bulk of G6PD deficient variants in this province and G6PD-Chatham and A- were encountered less frequently. Also that silent 1311 (C→T) mutation were common among G6PD-Mediterranean deficient variants individuals.     

Molecular Epidemiological Survey of Glucose-6-Phosphate Dehydrogenase Deficiency and Thalassemia in Uygur and Kazak Ethnic Groups in Xinjiang,Northwest China

Glucose-6-phosphate dehydrogenase (G6PD) deficiency and thalassemia occur frequently in tropical and subtropical regions, while the prevalence of relationship between the two diseases in Xinjiang has not been reported. We aimed to determine the prevalence of these diseases and clarify the relationship between genotypes and phenotypes of the two diseases in the Uygur and Kazak ethnic groups in Xinjiang. We measured G6PD activity by G6PD:6PGD (glucose acid-6-phosphate dehydrogenase) ratio, identified the gene variants of G6PD and α- and β-globin genes by polymerase chain reaction (PCR)-DNA sequencing and gap-PCR and compared these variants in different ethnic groups in Xinjiang with those adjacent to it. Of the 149 subjects with molecular analysis of G6PD deficiency conducted, a higher prevalence of the combined mutations c.1311C?>?T/IVSXI?+?93T?>?C and IVSXI?+?93T?>?C, both with normal enzymatic activities, were observed in the Uygur and Kazak subjects. A case of rare mutation HBB: c.135delC [codon 44 (?C) in the heterozygous state], a heterozygous case of HBB: c.68A?>?G [Hb G-Taipei or β22(B4)Glu→Gly] and several common single nucleotide polymorphisms (SNPs) were found on the β-globin gene. In conclusion, G6PD deficiency with pathogenic mutations and three common α-thalassemia (α-thal) [–?–^SEA, ?α^3.7 (rightward), ?α^4.2 (leftward)] deletions and point mutations of the α-globin gene were not detected in the present study. The average incidence of β-thalassemia (β-thal) in Uygurs was 1.45% (2/138) in Xinjiang. The polymorphisms of G6PD and β-globin genes might be useful genetic markers to trace the origin and migration of the Uygur and Kazak in Xinjiang.     

Glucosephosphate Isomerase (GPI) Deficiency Mutations Associated with Hereditary Nonspherocytic Hemolytic Anemia (HNSHA)

ABSTRACT: Five unrelated patients with hereditary glucosephosphate isomerase (GPI) deficiency resulting in nonspherocytic hemolytic anemia were studied. Three new mutations were found in the coding region of the GPI gene: two patients were heterozygous for 223 A→G (R75G) and 898 G→C(R300P), respectively and one was homozygous for 1415G→A(R472H). Surprisingly, 2 previously reported mutations, 286 C→T and 1039 C→T, were found in 2 and 3 patients respectively. Until now only 4 of 18 GPI mutations had been found more than once in unrelated patients and these 4 in only 2 patients each. Eleven of the 20 known point mutations have occurred at CpG “hot spots” and the 286 C→T and 1039 C→T are among these. The 489 G/A polymorphism in the GPI coding region was used to demonstrate unequivocally that the 1039 C→T mutation occurred in both haplotypes and therefore probably originated more than once. Because no common GPI mutation has been found we suggest that heterozygosity for GPI confers little if any selective advantage.     

Prevalence of Thalassemia and Glucose-6-Phosphate Dehydrogenase Deficiency in Newborns and Adults at the Ramathibodi Hospital,Bangkok, Thailand

Thalassemias and glucose-6-phosphate dehydrogenase (G6PD) deficiency are the most common inherited blood disorders. They are distributed among populations living in malaria endemic regions resulting in survival advantage from severe malaria disease. The aims of this study were to analyze the prevalence of thalassemias and G6PD deficiency at the Ramathibodi Hospital, Bangkok, Thailand. A total of 616 adult and 174?cord blood samples were collected and analyzed for red blood cell (RBC) parameters, hemoglobin (Hb) typing and DNA analysis for G6PD mutations and α-thalassemia (α-thal). The two most prominent types of thalassemia were heterozygous Hb E (HBB: c.79G>A), (19.5% in newborns and 35.6% in adults) followed by heterozygous α-thal-2 [–α^3.7 (rightward) deletion] at 18.7% in newborns and 19.5% in adults. After performing G6PD genotyping using multiplex amplification refractory mutation system-polymerase chain reaction (multiplex ARMS-PCR) for 10 G6PD mutations, the prevalence of G6PD mutation was found in 12.0% of newborns and 11.7% of adults. The G6PD Viangchan [871 (G>A)] is the most common G6PD mutation in newborns (42.9%) and adults (52.8%). In addition, coinheritance of various types of thalassemia with G6PD deficiency were found. The results indicated that heterozygous Hb E and G6PD Viangchan are predominant both in newborns and adults in this study.     

Molecular heterogeneity of glucose-6-phosphate dehydrogenase deficiency in Malays in Malaysia

Multiplex polymerase chain reaction (PCR) using multiple tandem forward primers and a common reverse primer (MPTP) was recently established as a comprehensive screening method for mutations in X-linked recessive diseases. In the work reported here, MPTP was used to scan for mutations of the glucose-6-phosphate dehydrogenase (G6PD) gene. Mutations in exons 3,4,5,6,7,9, 11, and 12 of the G6PD gene were screened by MPTP in 93 unrelated Malaysian patients with G6PD deficiency. Of the 93 patients, 80 (86%) had identified mutations. Although all of these were missense mutations, identified nucleotide changes were heterogeneous, with 9 mutations involving various parts of the exons. These 9 mutations were G-to-A nucleotide changes at nucleotide 871 of the G6PD gene (G871A), corresponding to G6PD Viangchan, G6PD Mediterranean (C563T), G6PD Vanua Lava (T383C), G6PD Coimbra (C592T), G6PD Kaiping (G1388A), G6PD Orissa (C131G), G6PD Mahidol (G487A), G6PD Canton (G1376T), and G6PD Chatham (G1003A). Our results document heterogeneous mutations of the G6PD gene in the Malaysian population.     

Target Gene Capture Sequencing in Chinese Population of Sporadic Parkinson Disease

Deciphering of genetic variants plays a critical role in research and clinic of genetic disorders, such as the well known neurodegenerative disease Parkinson disease (PD). To combine pool of targeted genes and next-generation sequencing (NGS), investigators could obtain high efficient but low-cost sequencing data of interested genes. Aim to discover genetic variants that might contribute to PD, we selected 48 candidate genes involved in different pathways and conducted a pilot study to screen nonsynonymous SNPs (nsSNPs) in 4 pooled samples from 237 sporadic Chinese PD patients. Using our custom-designed NimbleGen array and Illumina HiSeq2000, a total of 4 novel nsSNPs (c. 352G>T in STK39, c. 823G>T in DGKQ, c. 36T>A in DLA-DRB5, and c. 1981G>T in GRN) were discovered but not validated by Sanger sequencing. Additionally, we also selected 6 annotated nsSNPs without report in previous PD studies and validated by Sanger sequencing. However, genotyping analysis of 6 validated nsSNPs in 50 PD patients and 50 controls showed no significant differences in cases compared with controls. These data represent the first documentation and validation of these mutations in PD using target gene capture sequencing. Additional replication studies in other populations and functional research are merited to better evaluate precapture multiplex protocol and validate the role of the 6 nsSNPs in PD risk.     

Molecular heterogeneity of G6PD deficiency in an Amazonian population and description of four new variants

To characterize the molecular variation in the glucose-6-phosphate dehydrogenase gene (G6PD), 196 asymptomatic and unrelated male G6PD-deficient blood donors from Belém, an Amazonian metropolis (Brazil), were analyzed. This deficiency was detected by horizontal agarose gel electrophoresis and quantitative spectrophotometric assay for enzyme activity. The mutations were searched by PCR/RFLP, SSCP, and direct DNA sequencing. The most frequent G6PD variant was the widespread and common G6PD A- (202G --> A, 376A --> G) observed in 161 subjects (82.1%). Besides this, we found another form of G6PD A- (968T --> C, 376A --> G) in 14 (7.1%) individuals, G6PD Seattle (844G --> C) in 4.6%, G6PD Santamaria (542A --> T, 376A --> G) in 2.5%, and G6PD Tokyo (1246G --> A) in one blood donor. Four novel variants were also identified: G6PD Belém (409C --> T; Pro137His), G6PD Ananindeua (376A --> G, 871G --> A; Asn126Asp, Val291Met), G6PD Crispim with four point mutations (375G --> T, 379G --> T, 383T --> C, and 384C --> T) leading to three amino acid substitutions (Met125Ile, Ala127Ser, and Leu128Pro), and G6PD Amazonia (185C --> A; Pro62His). The reported frequencies do not reflect the real values for blood donors from Belém, since an excess of individuals with "non A-" phenotype was included in this study to enhance the probability to find rare variants. Haplotype analyses were carried out for the less common G6PD variants identified in our study using PCR/RFLP for five polymorphic sites (FokI, PvuII, PstI, BclI, NlaIII). G6PD Crispim and G6PD Amazonia variants presented the most common haplotype found in G6PD B (- - + - -). G6PD Belém presented two haplotypes (- - + + +, - + + + +) and G6PD Ananindeua was found with the + - + - + haplotype. The reported heterogeneity probably is due to the great miscegenation, characteristic of the population of the Amazonian region, besides the apparently common occurrence of recurrent mutations in the G6PD gene.     

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.     

Rapid detection of common Chinese glucose-6-phosphate dehydrogenase (G6PD) mutations by microarray-based assay

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy, affecting more than 200 million people worldwide. To date more than 123 mutations in the G6PD gene have been discovered, among which 12 point mutations are found in the Chinese. Setting up a simple and accurate method for detecting these mutations is not only useful for diagnosing G6PD deficiency under some circumstances that it is difficult to measure the activity of the enzyme, but also for studying the frequency of the G6PD genotypes. The purpose of this study was to develop a simple, inexpensive and accurate method for detecting these common mutations. Microarray-based assay was described in this study. Samples from 198 G6PD-deficient persons were investigated. The DNA sequencing data supported the results obtained by microarray-based assay. Thus, we concluded that the microarray-based assay is a rapid, simple, inexpensive, and accurate method for detecting the most common G6PD gene mutations among the Chinese. This method involves the selective amplification of human G6PD gene with specific oligonucleotide primers, fragmentation and labeling of PCR products, followed by hybridization with allele-specific oligonucleotide (ASO) probes on chip.     

Detection of β-Thalassemia Mutations Using a Multiplex Amplification Refractory Mutation System Assay

We developed two sets of a multiplex amplification refractory mutation system (M-ARMS) assay to identify specific β-thalassemia (β-thal) mutations that are common in Thailand. The first one was for the detection of mutants with codon 17 (A>T), IV S-I-1 (G >T)), codons 41/42 (?TCT T) and codons 71/72 (+A), while the second one was for the ?87 (C>A), ?28 (A>G) and IVS-II-654 (C>T). Application of the proposed assay to 282 persons with β-thal trait revealed a positive result in 276 cases (97.8%). There were 258 cases (91.5%) positive for the set 1 M-ARMS assay and 18 cases (6.4%) were positive for set 2. Six cases (2.2%) were negative for both sets 1 and 2, and were further characterized by DNA sequencing. The mutations detected by the set 1 M-ARMS assay were 113 cases (40.1%) of codons 41/42, 95 (33.7%) of codon 17, 41 (14.5%) of IVS-I-1 and nine cases (3.2%) of codons 71/72, while by set 2 there were 12 cases (4.2%) of ?28, four cases(1.4%) of ?87 and two cases (0.7%) of IVS-II-654. Mutations undetectable by M-ARMS assay were two cases of codons 27/28 (+C), one case of codon 35 (C>A), one of codon 43 (G>T), one of ?31 (A>G) and one of IVS-I-5 (C>G).

The M-ARMS assay proved to be a valuable tool for the analysis of β-thal mutations. The method is robust, accurate, simple, speedy and cost-effective. The application of this assay will facilitate genetic counseling and prenatal diagnosis for severe thalassemia in high-risk pregnancies.     

Molecular Basis of β-Thalassemia in the Western Province of Saudi Arabia: Identification of Rare β-Thalassemia Mutations

This study aimed at the identification of the spectrum of mutations in patients with β-thalassemia (β-thal) in the western province of Saudi Arabia. Screening for the mutations was done using the polymerase chain reaction-amplification refractory mutation system (PCR-ARMS) technique to test for 12 mutations, and direct automated DNA sequencing for the unknown samples. The study included 172 patients; of these 15 patients had sickle cell anemia and one Hb S [β6(A3)Glu→Val, GAG>GTG]/β-thal. A total of 23 mutations were identified to cause the disease in the western area. Seven common mutations were responsible for the β-thal alleles in 78% of patients and could be detected by the ARMS technique: IVS-II-1 (G>A), IVS-I-110 (G>A), IVS-I-5 (G>C), codon 39 (C>T), codon 26 (G>A) [Hb E or β26(B8)Glu→Lys, GAG>AAG], frameshift codons (FSC) 8/9 (+G), and IVS-I-1 (G>A). DNA sequencing of uncharacterized alleles detected eight less common mutations: FSC 41/42 (–TCTT), IVS-I 25 bp deletion, codon 37 (G>A), FSC 44 (–C), Cap site +1 (A>C), IVS-I-6 (T>C), FSC 5 (–CT) and IVS-I-1 (G>T), and eight rare mutations: ?87 (C>G), initiation codon ?1 (T>G), codon 15 (G>A), FSC 16 (–C), FSC 20/21 (+G), codon 27 (G>A), IVS-I-130 (G>C) and IVS-II-837 (A>C). Four alleles were normal by DNA sequencing. Genetic heterogeneity was observed in this study, 10 mutations were of Asian or Asian/Indian origin, two were Kurdish, one Chinese, one Turkish, one Saudi, and the remainder were of Mediterranean origin. The presence of a large population of immigrants in the western province is responsible for the great heterogeneity at the molecular level, and for the difference observed in the frequencies of mutations from those reported in the eastern province of Saudi Arabia. Screening for β-thal mutations using PCR-ARMS for the seven most frequent mutations in the Saudi population followed by DNA sequencing of the unknown alleles could be useful for the implementation of a strategy for carrier detection and preimplantation genetic diagnosis in high risk families.     

Prenatal Diagnosis of HbE-β-Thalassemia: Experience of a Center in Western India

The clinical presentation of HbE-β-thalassemia is extremely variable, however, many cases are severe and transfusion dependent. We offered prenatal diagnosis to 108 couples, 20 of whom came prospectively. CVS was done in 93 cases (9.5–13 weeks of gestation) while amniocentesis/cordocentesis was done for 15 cases in the second trimester. Diagnosis was done by reverse dot blot hybridization, ARMS, DNA sequencing and in a few cases by HPLC analysis of fetal blood. The genetic combinations in the couples at-risk were the following: HbE trait/β-thal trait-95, HbE-thal/HbE trait-5, HbE homozygous/β-thal trait-3, HbE-thal/β-thal trait-3, HbE Lepore/β-thal trait-1, HbE trait/HbD^Punjab trait-1. IVS1-5(G>C) was the commonest β-thalassemia mutation followed by codon15(G>A), codon30(G>C), codons41/42(-CTTT), the 619 bp deletion and codon8/9(+G) in the β-thalassemic parent. However, several rare mutations seen in India like -90(C>T), -88(C>T),codon15(-T), IVS1-129(A>C), IVS1-130(G>C), IVSII-1(G>A), IVSII-837(C>T) and IVSII 848(C>A) were also encountered. Twenty-one fetuses were affected (HbE-β-thal-20, β-thal major-1) and all the couples opted for termination of the pregnancies. Couples with affected children wish to undergo prenatal testing for HbE-β-thal in subsequent pregnancies. More regional centers are needed for these services, particularly in West Bengal and the North-East where HbE is very common.     

Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in Pakistani population

Introduction: Glucose‐6‐phosphate dehydrogenase (G6PD; E.C. 1.1.1.49) deficiency is the commonest inborn error of metabolism with more than 140 genetic variants. The incidence of G6PD deficiency is 2–9% in Pakistan, but G6PD variants were never studied comprehensively. We therefore designed this study to describe the frequency of G6PD variants and their associated enzyme activities in Pakistan. Methods: Patients diagnosed with G6PD deficiency were enrolled. RFLP‐PCR was utilized to identify common mutations previously reported from Asian countries. Where mutational analysis failed, amplification of 9–12 exons with subsequent gene sequencing was performed. G6PD enzyme activity was assessed through the quantitative enzyme assay. Results: Two hundred and seventy‐six G6PD‐deficient subjects (237 male and 39 women) were investigated. G6PD Mediterranean (563C‐T) was the most common genetic variant (n = 216 or 78%). G6PD Chatham (1003A‐G) and G6PD Orissa (131C‐G) were observed in 14 (5%) and two (0.7%) subjects respectively. A novel mutation 973 G‐A with a predicated amino acid change of asp325asn was identified in exon 9. This was named G6PD Karachi after the place of origin of proband. Polymorphism in position 1311C/T was uniformly observed with all variants. Forty‐three or 17% of DNA samples remained uncharacterized. Very low levels of G6PD enzyme activity was observed with 563C‐T mutation. Conclusion: We concluded that 563C‐T was the commonest G6PD variant, while 1003A‐G and 131C‐G were less‐frequent genetic variants of G6PD in Pakistani population. A novel genetic variant 973G‐A was also identified. Very low levels of G6PD enzyme activity was seen with G6PD 563C‐T. Mutational analysis failed in a significant proportion of samples warranting further work.     

Molecular Updating of β-Thalassemia Mutations in the Upper Egyptian Population

We have updated the dataset of the molecular spectrum of the β-thalassemia (β-thal) in Upper Egypt. Buccal swabs were analyzed from 94 unrelated patients with β-thal major (β-TM) using reverse dot-blot and multiplex amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). The most frequent mutation was IVS-I-110 (G>A) (57%). The IVS-I-110, IVS-I-6 (T>C) and IVS-I-1 (G>A) mutations accounted for 87% of the β-thal anomalies. The codon 39 (C>T) and frameshift codon (FSC) 6 (–A) (GAG>–GG) mutations were only detected in Al-Minya and Qina, respectively. We did not observe the IVS-II-745 (C>G) or –101 (C>T) mutations. Forty-three percent of Upper Egyptians were homozygotes. Our efforts were an important step to complete the mutation map of β-thal in Egypt restricted to Cairo and the Nile Delta regions. This study will help to develop preventative programs for Upper Egyptians. It addressed the genetic drift of the β-thal gene mutations in Africa, Asia, and Europe.     

Multiplex primer extension reaction screening and oxidative challenge of glucose-6-phosphate dehydrogenase mutants in hemizygous and heterozygous subjects

The primary objective of our study was to provide a simple and reliable assay for identifying the majority of G6PD genetic variants in the Chinese population. We optimized the multiplex primer extension reaction (MPER) assay for simultaneous screening of 14-point mutations in 98 G6PD-deficient subjects. Our data demonstrated that this method is precise, cost-effective and has successfully identified mutations in 97 out of 98 subjects, including all heterozygous mutants. We also detected a relatively high incidence (12.3%) of c.871G > A, and all of them harbored the silent mutation c.1311C > T. Apart from the screening program, the pharmacogenetic relationship between G6PD level and residual reduced glutathione (GSH) level was studied upon oxidative challenge by alpha-naphthol. The GSH levels were correlated with their status of G6PD deficiency, but no significant difference was observed between individual G6PD-deficient groups. Our data demonstrated the potentials of the MPER assay for characterization of G6PD deficiency and other genetic diseases.     

Clinical and haematological consequences of recurrent G6PD mutations and a single new mutation causing chronic nonspherocytic haemolytic anaemia

We have determined the causative mutation in 12 cases of glucose-6-phosphate dehydrogenase deficiency associated with chronic non-spherocytic haemolytic anaemia. In 11 of them the mutation we found had been previously reported in unrelated individuals. These mutations comprise seven different missense mutations and a 24 base pair deletion, G6PD Nara, previously found in a Japanese boy. Repeated findings of the same mutations suggests that a limited number of amino acid changes can produce the CNSHA phenotype and be compatible with normal development. The one new mutation we have found, G6PD Serres, is 1082 C → T causing a 361 Ala → Val substitution in the dimer interface where most other severe G6PD mutations are found. Now that several patients with the same mutation have been reported we can compare the resulting clinical phenotypes. For each mutation we find a reasonably consistent clinical picture, ranging from mild (G6PD Clinic) through moderate (G6PD Nashville) to severe (G6PD Beverly Hills and G6PD Nara).     

Characterization of Three Novel δ Chain Hemoglobin Variants and Two δ-Thalassemia Alleles

We report the characterization of five novel δ-globin gene mutations detected during routine screening for thalassemia. Three missense mutations were identified, resulting in the following δ chain hemoglobin (Hb) variants: Hb A₂-Acacias [δ4 (ACT>AGT), Thr→Ser, HBD c.14C>G], Hb A₂-Toronto [δ74 (GGC>GAC), Gly→Asp, HBD c.224G>A], and Hb A₂-Calgary [δ99 (GAT>GGT), Asp→Gly, HBD c.299A>G]. Two other mutations most likely result in δ⁰-thalassemia (δ⁰-thal). One mutation altered the translation initiation codon from ATG to ATA (HBD c.3G>A), and another changed the canonical splice donor sequence of IVS-II from GT to AT (HBD C.315+1G>A).     

Molecular Characterization of Glucose-6-Phosphate Dehydrogenase Deficiency among Jordanians

Background/Aims: In Jordan, glucose-6-phosphate dehydrogenase (G6PD) deficiency is a significant health problem, and the incidence was reported to be about 3.6%. The aims of this study are to investigate the most common molecular mutations of the G6PD gene among Jordanians in northern Jordan and to examine the correlation between the genotype and phenotype of this enzyme deficiency. Methods: Seventy-five blood samples were collected from patients attending King Abdullah University Hospital and Princess Rahma Teaching Hospital. The G6PD gene was scanned for mutations using a DNA sequencing technique. Results: Our results showed 11 variations (7 exonic and 4 intronic) as follows: c.202 G>A (rs1050828), c.376 A>G (rs1050829), c.404 A>C (CM962574 single-nucleotide polymorphism), c.542 A>T (rs5030872), c.563 C>T (rs5030868), c.1003 G>A (rs5030869), c.1311 C>T (rs2230037), c.486-90 C>T, c.486-60 C>G (rs2515904), c.770+175 C>T (rs2515905) and c.1311 C>T (rs2230037). Among these, G6PD Mediterranean (c.563 C>T) was the most common in our patients, with a frequency of 76.2%, followed by G6PD A- (c.202 G>A + c.376 A>G) with 19%, and an equal frequency of 1.6% was found for G6PD Chatham (c.1003 G>A), G6PD Santamaria (c.542 A>T + c.376 A>G) and G6PD Cairo (c.404 A>C). Conclusion: This is the first report of G6PD Santamaria and Cairo among our Jordanian population.     

Molecular Heterogeneity of β-Thalassemia in Algeria: How to Face Up to a Major Health Problem

This study concerns the molecular characterization of β-thalassemia (β-thal) alleles in 210 chromosomes. In the studied population, mutations were detected in 98% of the β-thalassemic chromosomes. Twenty-one molecular defects have been found, where the five dominant mutations, IVS-I-110 (G>A), nonsense mutation at codon 39 (C>T), the frameshift codon (FSC) 6 (?A), IVS-I-1 (G>A), and IVS-I-6 (T>C), account for 80% of the independent chromosomes. Among the remaining alleles, 16 different mutations were identified, half of them being described for the first time in Algeria. These include the ?101 (C>T) and the ?90 (C>T) mutations in the distal and proximal promoter elements, respectively, the FSC 8 (?AA), IVS-I-5 (G>T), IVS-I-128 (T>G), FSC 47 (+A), IVS-II-1 (G>A), and the substitution in the polyadenylation signal (poly A) site AATAAA>AATGAA. Haplotype analyses on rare variants were performed. The possible origin of these mutations either by founder effect or by migrations is discussed, and raises the question of an adequate strategy to be used adapted to socio-economical status.     

贵州省从江县侗族人群葡萄糖-6-磷酸脱氢酶基因突变型的检测

目的了解贵州省从江县侗族葡萄糖-6-磷酸脱氢酶(Glucose-6-phosphate dehydrogenase,G6PD) 缺乏症的发生率、基因突变类型及特点。方法对贵州省从江县侗族524人采用四氮唑蓝定性法进行G6PD缺乏症初筛、G6PD／6PGD比值法验证．再经自然引物及错配引物介导的聚合酶链反应／限制性酶切分析法检测中国人常见的9种基因突变型,对于未定型采用变性梯度凝胶电泳法(DGGE)检查外显子2、8、9、12基因突变情况。结果 G6PD缺乏症34例,检出率为6．49％,其中检出G1388A突变4例、C592T突变18例。未定型12例经DGGE检测外显子突变情况,未发现突变,有待于进一步对其余外显子进行研究。结论贵州省从江侗族是G6PD缺乏症的高发区。592 C→T突变型为该地该民族常见突变型,而不是中国人常见的G1376T、G1388A或A95G突变型。此次基因突变型调查为了解贵州省少数民族G6PD缺乏症的分布特征提供了原始数据。