Molecular basis of G6PD deficiency in India

G6PD deficiency has been reported from India more than 30 years ago and about 13 variants have been characterized biochemically. Here, we report the results of an epidemiological study investigating G6PD deficiency and the mutations among 14 heterogenous populations of India. Of the 3166 males tested, 332 (10.5%) were found to be G6PD-deficient and the prevalence rate varied from 5.7% to 27.9% in the different population groups. Molecular characterization revealed that G6PD Mediterranean (563 C-->T) was the commonest (60.4%) deficient variant followed by G6PD Kerala-Kalyan (949 G-->A; 24.5%) and G6PD Orissa (131 C-->G; 13.3%). G6PD Mediterranean had a more widespread distribution as compared to G6PD Kerala-Kalyan and G6PD Orissa and was associated with both 1311 C and 1311 T polymorhism. G6PD Mediterranean was found to have significantly lower red cell enzyme activity and more severe clinical manifestations than the other two. G6PD Chatham (1003 G-->A) with undetected red cell enzyme activity and G6PD Insuli (989 G-->A) with normal G6PD activity were very rare in the Indian population. The absence of a large number of mutations causing G6PD deficiency points to the fact that the genetic diversity of these populations is considerably lowered than expected.     

Molecular heterogeneity of glucose-6-phosphate dehydrogenase (G6PD) variants in the south of Thailand and identification of a novel variant (G6PD Songklanagarind)

Two hundred and twenty-five G6PD-deficient subjects in Songklanagarind Hospital in the south of Thailand comprising 210 males and 15 females were studied. Neonatal jaundice was detected in 85% of these patients. Acute hemolysis related to infection was detected in 17.3% of the G6PD-deficient subjects. Drug-induced acute hemolysis was detected in 1.8% and favism was observed in 3.6% of G6PD-deficient patients. The molecular analysis was performed on 134 G6PD-deficient individuals by a combination of PCR-RFLP, multiplex polymerase chain reaction by multiple tandem forward primers and a common reverse primer assay (MPTP) and DNA sequencing to characterize the mutations of the samples with abnormal MPTP bands. We found 10 different missense G6PD mutations and the three most common variants were G6PD Viangchan 871,G-->A (31.3%), G6PD Kaiping 1388,G-->A (20.1%) and G6PD Mahidol 487,G-->A (17.2%) followed by G6PD Canton 1376,G-->T (9.7%), G6PD Union 1360,C-->T (2.2%), G6PD Gaohe 95,A-->G (1.5%), G6PD Quing Yuan 392,G-->T (0.7%), G6PD Mediterranean 563,C-->T (0.7%), G6PD Songklanagarind 196,T-->A (0.7%), silent mutation 1311,C-->T (6.7%), and uncharacterized variant (9%). A novel missense mutation at codon 196, TTC-->ATC in exon 4 of the G6PD gene predicting a single amino acid substitution, Phe66Ile was identified and we designated this novel class II variant as G6PD Songklanagarind. The G6PD variants among the Thais in the southern part are heterogeneous and G6PD Viangchan, Kaiping, Mahidol, and Canton variants account for about 78% of the cases. Our findings provide some evidence that G6PD Viangchan and Mahidol are common Southeast Asian variants and support the theory of genetic drifts throughout Southeast Asia.     

Two new glucose-6-phosphate dehydrogenase mutations causing chronic hemolysis

We describe two new missense mutations in the glucose-6-phosphate dehydrogenase (G6PD) gene associated with chronic hemolytic anemia: mutation 1205C-->A in exon 10 predicts the amino acid change 402Thr-->Asn in the b-sheet M of the polypeptide chain, within the dimer interface (G6PD Cov?o do Lobo); mutation 1366G-->A in exon 12 predicts the amino acid substitution 456Asp-->His in the a-helix N, at the protein surface (G6PD Figueira da Foz).     

Rapid detection of six common Chinese G6PD mutations by MALDI-TOF MS

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked hereditary enzymopathy. We describe here the techniques based on matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and multiprimer extension (multi-PEX) to detect the most common Chinese G6PD mutations, which are the single-point mutations G-->T at nt 1376, G-->A at nt 1388, A-->G at nt 95, G-->T at nt 392, C-->T at nt 1024, and C-->T at nt 1311. Fifteen samples were genotyped using this method coupled with direct sequencing, after identification of G6PD mutations by ARMS. In this study, we identified a mutation G-->T at nt 1376, which had been G-->A at nt 1388 using ARMS, while the result of sequencing corresponds with ours. This indicates the reliability of this method. Furthermore, since it can scan six common Chinese G6PD mutations simultaneously in one mass spectrum, this approach could be used to fast diagnose these G6PD mutations accurately in large-scale analysis.     

Glucose-6-phosphate dehydrogenase (G6PD) mutations and UDP-glucuronosyltransferase promoter polymorphism among G6PD deficient Kuwaitis

Screening of 1,080 Kuwaiti male blood donors for glucose-6-phosphate dehydrogenase (G6PD) deficiency revealed this condition in 70 (6.5%) individuals. Mutation analysis of all 70 G6PD deficient samples performed by PCR/RFLP and direct sequencing identified the 563C-->T (Mediterranean) in 72.9%, 202G-->A (A(-)) in 14.3%, 1003G-->A (Chatham) in 7.1%, and 143T-->C (Aures) in 1.4%. In 3 cases (4.3%) mutations remain unknown. Genotyping of all G6PD deficient samples for UDP-glucuronosyltransferase 1 (UDPGT1) gene promoter polymorphism revealed (ta)6/(ta)6 in 38.6%, (ta)7/(ta)7 in 15.7%, (ta)6/(ta)7 in 44.3%, and (ta)7/(ta)8 allele in 1.4% of cases. Thus, 4% of males in the Kuwaiti population have G6PD deficiency coexisting with low activity of the UDPGT1 promoter.     

The β-thalassaemia mutations in the population of Cyprus

We have identified the beta-thalassaemia alleles in nearly all known Turkish Cypriot beta-thalassaemia homozygotes and in over 700 Greek Cypriot beta-thalassaemia heterozygotes living on the island of Cyprus. The data confirmed earlier observations that the IVS-I-100 (G-->A) mutation is present for about 74-80%, while three other alleles [IVS-II-745 (C-->G), IVS-I-6 (T-->C), IVS-I-1 (G-->A)] occur at frequencies of 5-8%. Nearly identical percentages were observed for the two Cypriot groups, quite different from those for beta-thalassaemia patients from Greece and Turkey. This suggests close contacts between the two Cypriot communities during many centuries without a major recent influence from Greek or Turkish beta-thalassaemia carriers.     

Glucose-6-phosphate dehydrogenase deficiency in Portugal: biochemical and mutational profiles,heterogeneity, and haplotype association

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy. This deficiency in erythrocytes has a prevalence of 0.51 +/- 0.109 in the Caucasoid male population of Portugal. The frequency for deficiency-conferring genes is 0.39% in the Portuguese population. In the herein study populations males from areas of Portugal presenting with the highest prevalence of G6PD deficiency (Castelo Branco, Setúbal, Faro, and Lisbon) as well as similar subjects located in the border Center/North area of the country (Viseu) have been analyzed for biochemical parameters and screened for mutations and haplotype-associated mutations commensurate with G6PD deficiency. Six intragenic restriction fragment length polymorphisms (RFLPs) were studied: exon 5, nt 376 A -->G, FokI; intron 5, nt 611 C--> G, PvuII; intron 8, nt 163 C--> T, BspHI; exon 10, nt 116 G --> A, PstI; exon 11, nt 1311 C--> T, BclI; and intron 11, nt 93 T -->C, NlaIII. New haplotypes were constructed with the inclusion of intron 11, nt 93 T--> C, NlaIII, and only 5 of 64 possible haplotypes were found to show a marked linkage disequilibrium for several RFLPs and also for mutations and specific haplotypes. The control population (n = 168 males) presented the G6PD B variant and corresponded to haplotypes I (- - + + - -), Ia (- - + + - +), and VIIa (- - + + + +), in 91.8, 2.3, and 5.9%, respectively. The PCR and sequencing analysis of extracted DNAs from the deficient G6PD group showed 48.6% (16/33) of individuals with the G6PD A- mutation, corresponding to haplotype VIa (+ + - + - +); 9% (3/33) with the Betica mutation and 18% (6/33) with the Santa Maria mutation, both of them associated with haplotype IVa (+ - - + \- +); 6.1% (2/33) with the Mediterranean mutation associated with haplotype VIIa; 12.3% (4/33) with the Seattle mutation, 3.0% (1/33) with Gaohe mutation; and a new mutation, 3.0% (1/33), which we designated by G6PD Flores, all of them associated with haplotype I.     

Factor XIII deficiency: new nonsense and deletion mutations in the human factor XIIIA gene

We identified five disease-causing mutations in six factor XIII deficient patients from four unrelated families: two novel nonsense mutations (nucleotide 979C-->T corresponding to Arg326Stop; and nucleotide 2075G-->A corresponding to Trp691 Stop), one novel deletion of a single nucleotide (nucleotide 708G or 709G), one previously reported missense mutation (nucleotide 888C-->G corresponding to Ser295Arg), and a previously reported splice site mutation (nucleotide 319G-->T at the last position of exon 3). The phenotypic consequences of these mutations are discussed.     

Glucose-6-phosphate dehydrogenase deficiency in female octogenarians, nanogenarians, and centenarians

BACKGROUND: Age-related skewing of X-chromosome inactivation leading to glucose-6-phosphate dehydrogenase (G6PD) deficiency in elderly women in a population with prevalent G6PD gene mutations was investigated. METHODS: G6PD activity was measured biochemically. G6PD mutations were detected by polymerase chain reaction (PCR) and allele-specific extension, and analyzed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and Sequenom MassARRAY. X-chromosome inactivation was quantified by semiquantitative PCR for the HUMARA gene, before and after HpaII digestion. RESULTS: In 173 women (median age: 90 years; range, 80-107 years), 18 heterozygotes for G6PD mutations were identified. Three heterozygotes were G6PD deficient, owing to skewed X-chromosome inactivation affecting the wild-type allele. Fifteen heterozygotes, with skewing apparently affecting the mutant alleles, had normal but significantly lower G6PD levels. At 1.73%, G6PD deficiency was significantly more frequent than expected from population screening at birth. CONCLUSION: Due to skewed X-chromosome inactivation, elderly women in populations with prevalent G6PD mutations are at risk of G6PD deficiency.     

Semiquantitative screening test for G6PD deficiency detects severe deficiency but misses a substantial proportion of partially-deficient females

Neonatal screening for G6PD deficiency has long been established in many countries. The aim of the study was to determine whether the routine semiquantitative fluorescent spot test could detect all cases of G6PD deficiency, including those cases with partial deficiency (residual red cell G6PD activity between 20-60% of normal). We compared the results of G6PD screening by the semiquantitative fluorescent spot test and quantitative G6PD activity assay on a group of 976 neonates and 67 known female heterozygotes. The values for mean G6PD activity of G6PD-normal neonates and 293 healthy adult females were determined. There was no significant difference in the mean normal G6PD activity between the two racial groups in the neonates (669 Malays, 307 Chinese) and in the 293 healthy adult females (150 Malays, 143 Chinese) group. The values for the upper limits of total deficiency (20% of normal residual activity) for neonates and adult females were 2.92 U/gHb and 1.54 U/gHb, respectively. The upper limits of partial deficiency (60% of normal residual activity) were 8.7 U/gHb and 4.6 U/gHb respectively. The prevalence of G6PD deficiency among the male neonates was 5.1% (26) by both the fluorescent spot test and the enzyme assay method. The G6PD activity levels of all 26 cases of G6PD-deficient male neonates were < 20% normal (severe enzyme deficiency). In the female neonate group, the frequency of G6PD deficiency was 1.3% (6 of 472) by the fluorescent spot test and 9.35% (44 of 472) by enzyme assay. The 6 cases diagnosed as deficient by the fluorescent spot test showed severe enzyme deficiency (< 2.92 U/gHb). The remaining 38 female neonates had partial enzyme deficiency and all were misdiagnosed as normal by the fluorescent spot test. In the female heterozygote group, G6PD deficiency was diagnosed in 53% (35 of 67) by enzyme assay and in 7.5% (4 of 67) of cases by the fluorescent spot test. The 4 cases detected by fluorescent spot test had severe enzyme deficiency (<1.6 U/gHb). The remaining 31 (46.3%) cases, diagnosed as normal by fluorescent spot test, showed partial G6PD deficiency. In conclusion, we found that the semiquantitative fluorescent spot test could only diagnose cases of total G6PD deficiency and misclassified the partially-deficient cases as normal. In this study, the overall prevalence of G6PD deficiency was 3.28% by the semiquantitative fluorescent spot test and 7.17% by enzyme assay. This means that 3.9% of G6PD-deficient neonates were missed by the routine fluorescent spot test and they were found to be exclusively females. This study demonstrates a need to use a method that can correctly classify female heterozygotes with partial G6PD deficiency. The clinical implication is that these individuals may be at risk of the hemolytic complication of G6PD deficiency.     

Glucose-6-Phosphate Dehydrogenase Variants Associated with Favism in Thai Children

In a study conducted at Songklanagarind Hospital in the south of Thailand, the subjects were 225 patients (210 boys and 15 girls) with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Favism was found in 3.6% of the G6PD-deficient children. Approximately one half of the G6PD-deficient patients with favism were younger than 2 years. Sudden onset of anemia was found within 1 to 3 days after ingestion of dried fava beans. The classic features of favism, which are pallor, hemoglobinuria, and jaundice, were detected in all cases. To characterize the known G6PD mutations in Thai children, molecular analysis was performed for 8 G6PD-deficient children with favism by a combination of polymerase chain reaction-restriction fragment length polymorphism analysis and amplification refractory mutation system analysis. The G6PD variants in these children were G6PD Kaiping 1388,G-->A; G6PD Mahidol 487,G-->A; G6PD Viangchan 871,G-->A; and uncharacterized mutation with silent mutation 1311,C-->T.     

Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in the Kurdish population of Western Iran

A total of 1,000 school boys ages 14-18 years, were randomly selected from six schools of Kermanshah and screened for G6PD deficiency. Fifty-three out of 1,000 were found to be severely G6PD deficient giving a frequency of 5.3% for G6PD deficiency in males in Kermanshah. We performed DNA analysis on 68 G6PD deficient children, 52 school boys and 16 children with the history of favism and hemolytic anemia using a combination of PCR-RFLP technique, single strand conformation polymorphism (SSCP) analysis and DNA sequencing. Three polymorphic G6PD mutations were identified: G6PD Mediterranean, Chatham and Cosenza. The commonest allele was found to be the G6PD Mediterranean (91.2%) followed by the G6PD Chatham (7.3%) and the G6PD Cosenza (1.5%). Haplotype analysis revealed that 56 out of 62 (90%) G6PD Mediterranean was linked to haplotype BclI(+) (1311T). In contrast, all G6PD Chatham and Cosenza had haplotype BclI(-) (1311C). The polymorphism IVS11-93 (T-->C) was present in 88.5% of the subjects studied. Only 4/55 (7.3%) of the Mediterranean alleles were associated with the T form and were always related to the nt 1311C. Our findings indicate that the allele frequency of G6PD Mediterranean mutation in Kermanshah is higher than those from two Fars ethnic groups living in Northern and Southern Iran. Nevertheless, they are in strict accordance with a previous report of the prevalence of the G6PD Mediterranean in Kurdish and Middle East population. Also, of strong association of the G6PD Mediterranean mutation and the presence of the polymorphism nt 1311C-->T in the Kermanshah population demonstrate that the presence of this mutation may be the result of migrations that have taken place through the history of Iran.     

Association of glucose-6-phosphate dehydrogenase deficiency and X-linked chronic granulomatous disease in a child with anemia and recurrent infections

Patients with severe leukocyte G6PD deficiency may present with impairment of NADPH oxidase activity and a history of recurrent infections, mimicking the phenotype of chronic granulomatous disease. We report herein a child with recurrent infections who initially received the diagnosis of G6PD deficiency. His erythrocyte G6PD activity was reduced: 1.8 U/g Hb (normal: 12.1 +/- 2.1 U/g Hb). Further studies revealed that G6PD activity in neutrophils, mononuclear leukocytes, and Epstein-Barr virus-transformed B-lymphocytes from the proband was similar to healthy controls. Molecular studies showed that the G6PD deficiency was due a 202 G-->A mutation, the A- variant common in African ethnic groups. The proband also exhibited severely impaired respiratory burst activity, as observed in X-linked CGD. Sequence analysis of genomic DNA showed a 264 G-->A substitution at the 3' splice junction of gp91-phox exon 3. The cDNA sequence showed a deletion of gp91-phox exon 3, giving rise to an unstable or nonfunctional mutant gp91-phox and to the phenotype of X-linked CGD. We propose that clinicians treating a patient with G6PD deficiency during a severe infection episode consider the possibility of temporary or permanent impairment of the phagocytes' microbicidal activity and the eventual association of G6PD deficiency and chronic granulomatous disease.     

A new glucose-6-phosphate dehydrogenase variant G6PD Sugao (826C-->T) exhibiting chronic hemolytic anemia with episodes of hemolytic crisis immediately after birth

A case of glucose-6-phosphate dehydrogenase (G6PD) deficiency associated with chronic hemolysis with episodes of hemolytic crisis immediately after birth is reported. The propositus was a 1-month-old Japanese male infant. Molecular analysis of the G6PD gene revealed a novel missense mutation (826C-->4T) in exon 8 predicting a single amino acid substitution, Pro276Ser. The mother was confirmed to be heterozygous for this mutation. We designated this novel class 1 variant as G6PD Sugao. Pro276 is a phylogenetically conserved residue that may play a significant role in dimer formation.     

Genetic heterogeneity of beta-thalassemia at Cukurova in southern Turkey

Beta-thalassemia is the most common genetic abnormality causing health problems worldwide. Cukurova, in the southern part of Turkey, being on the Mediterranean, is in the thalassemic belt. Since there is no cure for the disease at present, the frequency of the mutation types of beta-thalassemia must first be identified to aid in clinical follow-up and prenatal diagnosis. Carriers identified during a screening survey and patients referred to our laboratory were studied for this purpose. After routine hematological analysis molecular screening was performed by the amplification refractory mutation system and DNA sequencing. The frequency of the common mutations were: IVS-I-110 (G-->A) 57.3%, IVS-I-1 (G-->A) 8.3%, codon 39 (C-->T) 6.4%, IVS-I-6 (T-->C) 5.7%, frameshift codon 8 (-AA) 5.7%, -30 (T-->A) 4.7%, IVS-II-1 (G-->A) 3.4%, IVS-II-745 (G-->C) 2.8%, and frameshift codon 5 (-CT) 1.1%. Some rare mutations (1%) such as frameshift codon 44 (-C) 0.7%, frameshift codons 74/75 (-C) 0.7%, IVS-1-5 (G-->C) 0.7%, frameshift codons 8/9 (+G) 0.4%, frameshift codons 36/37 (-T) 0.4%, frameshift codons 22/23/24 (-AAGTTGG) 0.4%, IVS-1-130 (G-->C) 0.4%, IVS-1-5 (G-->T) 0.2%, -28 (A-->C) 0.2%, codon 15 (TGG-->TGA) 0.2%, and frameshift codons 82/83 (-G) 0.2%, were detected by sequence analysis. The codon 15 (TGG-->TGA) and frameshift codons 82/83 (-G) mutations were seen in Turkey for the first time.     

Modification to reporting of qualitative fluorescent spot test results improves detection of glucose-6-phosphate dehydrogenase (G6PD)-deficient heterozygote female newborns

Introduction: The glucose‐6‐phosphate dehydrogenase (G6PD) fluorescent spot test (FST) is a useful screening test for G6PD deficiency, but is unable to detect heterozygote G6PD‐deficient females. We sought to identify whether reporting intermediate fluorescence in addition to absent and bright fluorescence on FST would improve identification of mildly deficient female heterozygotes. Methods: A total of 1266 cord blood samples (705 male, 561 female) were screened for G6PD deficiency using FST (in‐house method) and a quantitative enzyme assay. Fluorescence intensity of the FST was graded as either absent, intermediate or normal. Samples identified as showing absent or intermediate fluorescence on FST were analysed for the presence of G6PD mutations using TaqMan@SNP genotyping assays and direct nucleotide sequencing. Results: Of the 1266 samples, 87 samples were found to be intermediate or deficient by FST (49 deficient, 38 intermediate). Of the 49 deficient samples, 48 had G6PD enzyme activity of ≤ 9.5 U/g Hb and one sample had normal enzyme activity. All 38 intermediate samples were from females. Of these, 21 had G6PD activity of between 20% and 60%, and 17 samples showed normal G6PD activity. Twenty‐seven of the 38 samples were available for mutation analysis of which 13 had normal G6PD activity. Eleven of the 13 samples with normal G6PD activity had identifiable G6PD mutations. Conclusion: Glucose‐6‐phosphate dehydrogenase heterozygote females cannot be identified by FST if fluorescence is reported as absent or present. Distinguishing samples with intermediate fluorescence from absent and bright fluorescence improves detection of heterozygote females with mild G6PD deficiency. Mutational studies confirmed that 85% of intermediate samples with normal enzyme activity had identifiable G6PD mutations.     

Molecular characterization of a German variant of glucose-6-phosphate dehydrogenase deficiency (G6PD Aachen)

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-chromosome-linked hereditary disorder. Clinically, patients with G6PD deficiency often present with drug- or food-induced hemolytic crises or neonatal jaundice. G6PD is involved in the generation of NADPH and reduced glutathione. In contrast to American, Mediterranean, and African ancestries, only few variants are known from Middle and Northern Europe. We describe the molecular characterization of a distinct variant from the northwestern area of Germany, G6PD Aachen. The sequence of the G6PD gene from three afflicted males was found to be hemizygous at cDNA residue 1089 for a C-->G mutation with a predicted amino acid change of Asn363Lys. The 1089 C-->G point mutation is unique, but produces the identical amino acid change found in a Mexican variant of G6PD deficiency, G6PD Loma Linda. This G6PD-deficient variant is caused by a 1089 C-->A mutation. The 363-amino-acid replacement is located outside a known mutation cluster region between amino acid residues 380 and 450, but may disrupt or weaken dimer interactions of G6PD enzyme subunits.     

Novel mutations in the Factor VII gene of Taiwanese Factor VII-deficient patients

The genetic defects of four Taiwanese patients with factor VII (FVII) deficiency were studied. FVII activity and antigen levels were < 1 u/dl and 125.7 u/dl (patient I), < 1 u/dl and < 1 u/dl (patient II), 3.4 u/dl and 5.9 u/dl (patient III), and 1.2 u/dl and 30.4 u/dl (patient IV) respectively. The 5' flanking region, and all exons and junctions were amplified using polymerase chain reaction and sequenced. Patient I was homozygous for a 10824C-->A transversion with Pro303-->Thr mutation in exon 8. In patient II, a heterozygous transversion, 9007+1G-->T at the IVS6, a heterozygous decanucleotide insertion polymorphism at -323 (both mutations present in his father) and a heterozygous deletion, del TC (26-27) in exon 1A (originating from his mother) were identified. Patient III had a homozygous 10961T-->G transversion with His348-->Gln mutation in exon 8. Patient IV had a heterozygous 10902T-->G transversion with Cys329-->Gly mutation in exon 8 (transmitted to her second son) and a heterozygous decanucleotide insertion polymorphism at -323 (transmitted to her third son). All but one of the FVII gene mutations detected in the four patients have not been previously reported. In conclusion, four novel mutations of the FVII gene in Taiwanese, including two missense mutations in exon 8, one point mutation at the exon 6 splice site and one deletion in exon 1A, were identified.     

海南省陵水县黎族人群红细胞葡萄糖-6-磷酸脱氢酶缺乏症基因频率调查

目的：在疟疾流行区建立红细胞葡萄糖－６－磷酸脱氢酶缺乏者个人档案，以预防伯氨喹溶血反应的发生。方法：用四氮唑蓝（ＮＢＴ）法测定红细胞葡萄糖－６－磷酸脱氢酶活性。结果与结论：２４３９名黎族人群红细胞葡萄糖－６－磷酸脱氢酶缺乏症基因频率为０．１７５９，其女性杂合子发生率为２８．３３％，纯合子发生率为３．０９％。     

The beta+-IVS-I-6 (T-->C) mutation accounts for half of the thalassemia chromosomes in the Palestinian populations of the mountain regions

A study of the spectrum of beta-thalassemia mutations in the southern part of the West Bank of the Palestinian Authority revealed the presence of 10 different beta-globin mutations. The study included 41 patients and 54 carriers of beta-thalassemia and sickle cell anemia. The spectrum of mutations observed was typically Mediterranean. However, their relative frequencies was unique. The predominant allele was IVS-I-6 (T-->C), with an exceptionally high frequency of 48.5% for this mutation. The homozygous IVS-I-6 patients had widely variable clinical presentations, from typical transfusion-dependent thalassemia major to non-transfusion-dependent thalassemia intermedia phenotype. Since it is so widespread in these West Bank populations, the IVS-I-6 mutation may date back to ancient times. The nonsense mutation at codon 37 (G-->A) was found at a relatively high frequency of 11.3%, supporting the hypothesis that it originated in this region. The other mutations, at decreasing frequencies ranging from 9.5-1.5%, were: IVS-I-110 (G-->A), frameshift codon 5 (- CT), IVS-I-1 (G-->A), IVS-II-1 (G-->A), Hb S [beta6(A3)Glu-->Val], frameshift codons 8/9 (+G), codon 39 (C-->T), and -30 (T-->A). Our findings will improve health care for the Palestinian population, and also has implications for the study of the origin and spread of thalassemia in the Middle East.