Spectrum of beta-globin gene mutations among thalassemia patients in the West Bank region of Palestine

beta-Thalassemia (thal) is an autosomal recessive disorder that results in hypochromic hemolytic anemia in affected patients. In the West Bank area of Palestine, the prevalence of beta-thal trait is approximately 3.5% among the population, with an estimated 120,000 carriers. Seventeen beta-globin gene mutations could be identified in 148 patients using polymerase chain reaction (PCR), amplification refractory mutation system (ARMS)-PCR and direct sequencing. The predominant mutations included: IVS-I-6 (T --> C) (28.7%), IVS-I-110 (G --> A) (17.6%), codon 37 (G --> A) (10.4%), IVS-I-1 (G --> A) (9%), codons 106/107 (+ G) (6.8%) and codon 39 (C --> T) (4.6%). Other less frequent and rare mutations included: IVS-II-1 (G --> A), codon 5 (-CT), IVS-II-848 (C --> A), -30 (T --> A), codons 8/9 (+ G), IVS-I-5 (G --> C), -28 (A --> C), IVS-II-745 (C --> G), codon 6(-A), codon 27 (G --> T) and codon 30 (AGG --> ACG). Most patients (62.2%) were homozygous for one type of mutation, while the rest (27.3%) were compound heterozygotes. Some patients were heterozygous for beta-thal and sickle cell anemia traits. No mutations could be detected in both alleles of eight patients, while in seven patients only one mutant allele could be detected. Further investigations are needed to resolve the corresponding genotypes of these patients. This study represents a comprehensive investigation of the type, frequency, and distribution of thalassemia mutations among the Palestinian population in the West Bank region of Palestine. A degree of similarity and significant variations was evident in the type and frequency of mutations when the present mutations profile was compared with similar ones among various Arab and non Arab populations. The association between the identified mutations and the corresponding genotypes of our patients with specific polymorphism frameworks in the beta-globin gene was performed and the results revealed linkage disequilibrium.     

Detection of beta-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 beta-thalassemia (beta-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 beta-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 beta-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 spectrum of beta-thalassemia mutations in Northwestern Iran

Beta-thalassemia (beta-thal) is a hereditary autosomal disorder with decreased or absent beta-globin chain synthesis. This study was designed to identify the common and rare beta-thal mutations in the Azerbaijan provinces, Northwestern Iran, and to set up a prenatal diagnostic laboratory. One hundred unrelated patients with known beta-thal major and intermedia, registered with the thalassemia clinics in the provincial capitals of Tabriz and Ardebil, were included. Mutations were studied in 200 chromosomes, by polymerase chain reaction-amplification refractory mutation system (PCR-ARMS) and direct sequencing methods. We found 17 beta-thal mutations in this region of Iran. The results showed that IVS-II-1 (-->GA) was the most frequent mutation, comprising 21% of all mutations. Other common mutations were IVS-I-110 (-->GA) 18%, frameshift codons (FSC) 8/9 (+G) 14.5%, FSC 8 (-AA) 8% and IVS-I-1 (GA) 7.5%. This is the first comprehensive study in this region and could be useful for developing a beta-thal molecular screening in Azerbaijan-Iran.     

The molecular analysis of beta-thalassemia mutations in Lorestan Province, Iran

Beta-Thalassemia (thal) is one of the most common genetic disorders in Iran and other countries. Getting information on the distribution of mutations in different ethnic groups of Iran is of fundamental importance for the purpose of health planning and prenatal diagnosis programs. One hundred and thirty chromosomes from 65 unrelated homozygous beta-thal patients were investigated for beta-globin gene mutations by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). The most common mutations of the Mediterranean region were examined in this study. Our results showed that the frameshift codons (FSC) 36/37 (-T) mutation, with a frequency of 33.8%, is the most common mutation in Lorestan Province. The other most frequent mutations were of the Mediterranean type and consisted of IVS-II-1 (G -->A), IVS-I-110 (G -->A), FSC 8/9 (+G) and IVS-I-5 (G -->C) with frequencies of 27.7, 11.5, 10.8 and 4.5%, respectively. The less frequent alleles, IVS-II-745 (C -->G), FSC 5 (-CT), IVS-I (25 bp deletion) and FSC 44 (-C) accounted for only 3.9% of the mutations. The unknown alleles comprised 7.7% of the mutations. These data showed that the spectrum of mutations found in Lorestan Province was different from those reported from other thalassemic regions of Iran and also of some neighboring countries.     

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 beta-thalassemia in the population of Tunisia

The present study attempts to delineate the spectrum of beta-thalassemia (thal) mutations in Tunisia by studying a large population from different parts of the country. A total of 285 unrelated subjects, 190 of whom had beta-thal major, 72 with Hb S/beta-thal, one with Hb C/beta-thal, one with Hb O-Arab/beta-thal and 21 beta-thal carriers, were studied. The molecular defects were detected in 97.7% of the beta-thalassemic chromosomes (n=475). Nineteen different beta-thalassemic alleles were identified. Two mutations, namely codon 39 (C-->T) and IVS-I-110 (G-->A) accounted for 70.0% of the studied chromosomes, followed by IVS-I-1 (G-->A) (4.5%). Five other mutations, frameshift codon (FSC) 44 (-C), codon 30 (G-->C), IVS-I-2 (T-->G), IVS-II-745 (C-->G), and FSC 6 (-A), are not uncommon in this population, while the remaining 11 mutations, IVS-I-5 (G-->A), -30 (T-->A), codons 25/26 (+T), IVS-I-6 (T-->C), FSC 5 (-CT), IVS-II-848 (C-->A), FSC 8 (-AA), -87 (C-->G), IVS-I-5 (G-->C), IVS-II-1 (G-->A) and IVS-II-849 (A-->C) are quite rare; four of these have not been previously reported in the Tunisian population. Potential origin and spread of these mutations to Tunisia are also discussed.     

A different molecular pattern of beta-thalassemia mutations in northeast Brazil

The main hereditary hemoglobin (Hb) disorders of clinical significance in Brazil are sickle cell disease and beta-thalassemia (thal). The sickle gene was introduced by the slave trade, whereas beta-thal was introduced later, due to a massive immigration (mostly by Italians) between 1870 and 1953, mainly to the southeast region of Brazil. Molecular studies performed in the southeast of the country showed a marked prevalence of the nonsense mutation at codon 39 (C --> T) (47-54%), leading to severe forms of beta0-thal. However, the northeast region of the country has a different demographic history, characterized by the absence of the massive Italian immigration. Owing to this and since the majority of cases of beta-thal in Pernambuco, a state located in the northeast of the country, have mild or intermediate clinical and laboratory features, we would predict a different spectrum of beta-thal mutations in this region. We examined 60 unrelated patients (86 beta-thal chromosomes) under regular clinical follow-up in Pernambuco: 6 were regularly transfused beta-thal major subjects, 20 had beta-thal intermedia, 20 had Hb S/beta-thal and 14 were beta-thal trait individuals. The following mutations were found: IVS-I-6 (T --> C) 62.8%, IVS-I-1 (G -->A) 15.1%, IVS-I-5 (G --> C) 9.3%, IVS-I-110 (G --> A) 8.2%, codon 39 (C --> T) 3.5%, and codon 30 (AGG --> AGC) 1.1%. These data show different patterns of beta-thal mutations in two regions of Brazil, demonstrating a thus far unrevealed heterogeneity of the disease in the country.     

Molecular spectrum of β-thalassemia mutations in the admixed Venezuelan population, and their linkage to β-globin gene haplotypes

In order to establish the spectrum of β-thalassemia (β-thal) mutations in the Venezuelan population for the first time, 127 unrelated subjects either with a suspicion of β-thal trait or with a clinically recognized β-thal syndrome of different degrees of severity, were studied. DNA from these subjects was analyzed by a polymerase chain reaction (PCR)-based reverse dot-blot method or amplification refractory mutation system (ARMS). Prototype β-globin gene sequencing of relevant DNA was performed to confirm the mutations. Fifteen different mutations were identified accounting for 92.0% of the mutant alleles explored, revealing a significant genetic heterogeneity at the β-globin gene locus in this population. The most frequent mutations were codon 39 (C >T) 34.1%, IVS-I-1 (G >A) 11.1%, IVS-I-6 (T > C) 6.6%, IVS-I-110 (G >A) 6.6%, IVS-II-849 (A >G) 6.6%, -88 (C >T) 6.0%, -29 (A >G) 5.2%, followed by the less common IVS-I-5 (G >A) 3.7%, the 1,393 bp deletion 3.0%, IVS-II-1 (G >A) 3.0%, -86 (C >G) 2.2%, IVS-II-1 (G >T) 1.5%, codons 41/42 (-TCTT) 1.5%, IVS-II-745 (C >G) 0.7% and deletional δβ-thal 0.7%. Overall, these data demonstrate that the major sources of β-thal alleles in Venezuela, as expected, are of Mediterranean and African origins. This is the first large study defining the molecular spectrum of β-thal in the highly admixed population of Venezuela and lays the foundation for genetic counseling as well as implementing comprehensive clinical care programs. Diversity of haplotypes associated with some of the β-thal mutations can be explained by in situ recombination events in Venezuela.     

Analysis of β‐Thalassemia Mutations in Northern Thailand Using an Automated Fluorescence DNA Sequencing Technique

A total of 218 β‐thalassemia (thal) genes from 109 β‐thal major patients were characterized using an automated fluorescence DNA sequencing technique. Eight different mutations were identified in all 218 alleles (100%). Four common mutations accounted for 96.8% [49.5% were codons 41/42 (–TTCT), 34.4% were codon 17 (A→T), 6.9% were IVS‐I‐1 (G→T) and, 6.0% were codons 71/72 (+A)]. There were three cases of ?28 (A→G) and one of IVS‐II‐654 (C→T), mutations that have been previously described in Thai subjects. We also identified two mutations in the β‐globin promoter region which have not been reported in Thailand before [?31 (A→G) and ?87 (C→A)]. Although these mutations are described as β⁺‐thal, the compound heterozygote with one of the common β⁰‐thal mutations exhibits the phenotype of β‐thal major. The frequency of β‐thal genes in northern Thailand were similar to the northeastern region, but different from those reported in southern and central Thailand, where IVS‐I‐5 (G→C) and IVS‐II‐654 (C→T) were the second most common anomalies, respectively. The spectrum of β‐globin gene mutations from this study will be useful for planning a prenatal diagnosis program especially for this region of Thailand.     

Distribution of β-Thalassemia Mutations in the Northern Provinces of Iran

β-Thalassemia (thal) is one of the most common autosomal recessive disorders in Iran. There are more than two million carriers of β-thal and over 15,000 people affected with β-thal major who live in Iran. Prevalent mutations were identified by examining genomic DNAs isolated from 392 blood samples of β-thal carriers from three northern provinces of Iran. Furthermore, 172 pregnant women were analyzed from the 196 couples who requested pregnant diagnosis for β-thal. Allele identification was carried out using routine reverse dot-blot, amplification refractory mutation system (ARMS), and genomic sequencing. The most common mutation, IVS-II-1 (G→A), is followed, in order of frequency, by codon 30 (G→C), frameshift codons (FSC) 8,9 (+G), FSC 22/23/24 (?AAGTTGG), IVS-I-110 (G→A), IVS-I-5 (G→C), IVS-II-745 (C→G), IVS-I-2 (T→C), FSC 8 (?AA), IVS-I,3′-end (?25 bp), IVS-I-1 (G→A), FSC 36/37 (?T), IVS-I-6 (T→C), FSC 5 (?CT), ?28 (A→C), codon 37 (G→A), IVS-II-2,3 (+11/?2), ?30 (T→A), and ?88 (C→A). We have also revealed the existence of five new mutations from northern Iran, one of which (codon 37) is the first reported for Iran. Furthermore, the rate of unknown mutations is significantly reduced in our study (about 6%). These results could help with establishing a center for prenatal diagnosis, prevention, and control of thalassemia in the northern provinces of Iran.     

PROFESSOR TITUS H. J. HUISMAN'S 40 YEARS AT THE MEDICAL COLLEGE OF GEORGIA

β-Thalassemia (thal) is an autosomal recessive disorder that results in hypochromic hemolytic anemia in affected patients. In the West Bank area of Palestine, the prevalence of β-thal trait is approximately 3.5% among the population, with an estimated 120,000 carriers. Seventeen β-globin gene mutations could be identified in 148 patients using polymerase chain reaction (PCR), amplification refractory mutation system (ARMS)-PCR and direct sequencing. The predominant mutations included: IVS-I-6 (T→C) (28.7%), IVS-I-110 (G→A) (17.6%), codon 37 (G→A) (10.4%), IVS-I-1 (G→A) (9%), codons 106/107 (+ G) (6.8%) and codon 39 (C→T) (4.6%). Other less frequent and rare mutations included: IVS-II-1 (G→A), codon 5 (–CT), IVS-II-848 (C→A), –30 (T→A), codons 8/9 (+ G), IVS-I-5 (G→C), –28 (A→C), IVS-II-745 (C→G), codon 6 (–A), codon 27 (G→T) and codon 30 (AGG→ACG). Most patients (62.2%) were homozygous for one type of mutation, while the rest (27.3%) were compound heterozygotes. Some patients were heterozygous for β-thal and sickle cell anemia traits. No mutations could be detected in both alleles of eight patients, while in seven patients only one mutant allele could be detected. Further investigations are needed to resolve the corresponding genotypes of these patients. This study represents a comprehensive investigation of the type, frequency, and distribution of thalassemia mutations among the Palestinian population in the West Bank region of Palestine. A degree of similarity and significant variations was evident in the type and frequency of mutations when the present mutations profile was compared with similar ones among various Arab and non Arab populations. The association between the identified mutations and the corresponding genotypes of our patients with specific polymorphism frameworks in the β-globin gene was performed and the results revealed linkage disequilibrium.     

Detection of rare beta-thalassemia mutations by denaturing gradient gel electrophoresis among Indians

We report four rare beta-thalassemia (thal) mutations, viz. AATAAA --> AACAAA [polyadenylation (poly A) site mutation]. IVS-II-745 (C --> G), codon 121 (G --> T) and IVS-II-1 (G --> A), detected by denaturing gradient gel electrophoresis (DGGE) among Indians. Of these, the poly A site mutation has been found in combination with deletional delta(beta)-thal in one case, and with the IVS-1-5 (G --> C) mutation in another. Two DGGE patterns, corresponding to the same IVS-II-1 (G --> A) mutation, were seen in one family. Framework (FW) analyses in family studies have shown that the poly A site mutation is associated with FW-1, while both the codon 121 (G --> T) and IVS-II-1 (G --> A) mutations are associated with FW-2. Denaturing gradient gel electrophoresis facilitates the screening of rare beta-thal mutations in the diverse Indian population with its many ethnic groups, covering a vast geographic territory.     

Molecular Basis of β-Thalassemia in the Population of the Aegean Region of Turkey: Identification of A Novel Deletion Mutation

Abstract

β-Thalassemia (β-thal) is the most common monogenic disorder in Turkey. The aim of this study was to investigate the spectrum of β-thal mutations in the Aegean region of Turkey. The data was derived from 1171 unrelated β-thal subjects, detected in a regional reference hospital between November 2004 and December 2013. Screening for the 22 common mutations was performed using the polymerase chain reaction (PCR)-reverse dot-blot method, and direct automated DNA sequencing for the unknown samples. Thirty-one different β-thal alleles were identified. Seven mutations, namely IVS-I-110 (G?>?A) (41.7%), IVS-I-1 (G?>?A) (8.9%), IVS-II-745 (C?>?G) (8.6%), codon 8 (–AA) (7.7%), IVS-II-1 (G?>?A) (7.2%), IVS-I-6 (T?>?C) (6.6%), codon 39 (C?>?T) (4.6%) accounted for 85.3% of the mutated alleles. Frequencies of the remaining 24 β-thal mutations were less than 2.2%; these included one novel mutation [HBB: c.206_212del (p.Leu69Profs*19)], and four others [–56 (G?>?C), codon 16 (–C), IVS-I (–3) (C?>?T) (codon 29), codon 76 (–C)] found in Turkey for the first time. The results will help to prevent severe β-thal through genetic counseling and prenatal diagnosis (PND) in the Aegean region of Turkey.     

Molecular Characterization of β-Thalassemia in the Dohuk Region of Iraq

β-Thalassemia (thal) is an important health problem in the Dohuk region of northern Iraq because of its high carrier rate and the frequency of consanguineous marriages. Thus, the need to establish an effective preventative program is paramount. As part of this effort, we initiated this study to determine the molecular basis of this disorder in the region. For the latter purpose, either parent of 104 registered β-thal major/intermedia patients had their full blood counts, hemoglobin (Hb) electrophoresis, Hb A₂ and Hb F quantitation performed. Their DNA was extracted, amplified and reverse hybridized to specific oligonucleotide probes to detect 20 β-thal mutations. The testing detected 12 β-thalassemic mutations. The eight most frequent were: IVS-II-1 (G→A), codon 44 (–C), codon 5 (–CT), IVS-I-1 (G→A), codon 39 (C→T), IVS-I-6 (T→C), codons 8/9 (+G) and IVS-I-5 (G→C). These mutations accounted for 81.7% of the thalassemic defects in the studied individuals. The less frequent mutations were: codon 8 (–AA), IVS-I-110 (G→A), codon 30 (G→C) and codon 22 (?7 bp), and the β-thalassemic defects remained uncharacterized in 11.5% of cases. This is the first study of β-thal mutations from Iraq, and shows a frequency of thalassemic defects different from those reported in surrounding countries. It provides a foundation for prenatal genetic testing that will be part of a thalassemia prevention program in the Dohuk region.     

Origin of the frameshift codons 41/42 (-TCTT) mutation in the first cases described in the Spanish population

Thalassemias are hereditary anemias. In beta-thalassemia (beta-thal), beta-globin synthesis is either deficient or absent. A high incidence of beta-thal is found in populations of Mediterranean and African origin. Smaller, but significant concentrations of beta-thal are present throughout the Middle East, India, Pakistan and China, while sporadic cases have been reported in most ethnic groups. Over 200 beta-thal mutations have been described so far. But each population group displays its own mutations. In Spain, as in other countries of the Mediterranean region, the most often seen mutations are codon 39 (C > T); IVS-I-1 (G > A); IVS-I-6 (T > C) and IVS-I-110 (G > A). However, a large number of rarer alleles have been observed both in Spain and other populations. The frameshift codons (FSC) 41/CD42 (-TCTT) mutation is a rather common allele in individuals of Chinese origin, but rare in the Mediterranean region, although, it has been recorded in East Asian populations. We describe the first eight Spanish patients displaying the FSC 41/42 mutation. This mutation was initially detected with a real-time polymerase chain reaction (PCR) method on a LightCycle, using a probe designed to detect mutations in codons 37 and 39, and subsequently specifically characterized by automatic sequencing. The haplotype found in our patients suggested that this mutation has not arisen independently in our population but must be taken into account when identifying most beta-thal mutations.     

Molecular Spectrum of β-Thalassemia Mutations in Northwestern Iran

β-Thalassemia (β-thal) is a hereditary autosomal disorder with decreased or absent β-globin chain synthesis. This study was designed to identify the common and rare β-thal mutations in the Azerbaijan provinces, Northwestern Iran, and to set up a prenatal diagnostic laboratory. One hundred unrelated patients with known β-thal major and intermedia, registered with the thalassemia clinics in the provincial capitals of Tabriz and Ardebil, were included. Mutations were studied in 200 chromosomes, by polymerase chain reaction-amplification refractory mutation system (PCR-ARMS) and direct sequencing methods. We found 17 β-thal mutations in this region of Iran. The results showed that IVS-II-1 (G→A) was the most frequent mutation, comprising 21% of all mutations. Other common mutations were IVS-I-110 (G→A) 18%, frameshift codons (FSC) 8/9 (+G) 14.5%, FSC 8 (?AA) 8% and IVS-I-1 (G→A) 7.5%. This is the first comprehensive study in this region and could be useful for developing a β-thal molecular screening in Azerbaijan-Iran     

Multicenter study of the molecular basis of thalassemia intermedia in different ethnic populations

We studied 325 thalassemia intermedia patients from Iran, India, Pakistan, Thailand, Mauritius and Cyprus to examine factors which influence the phenotype. The beta-thalassemia (thal) mutations were determined for 219 beta-thal/beta-thal and 106 beta-thal/Hb E [beta26(B8)Glu-->Lys, GAG-->AAG] thalassemia intermedia patients. Thirty-one different mutations were identified, and their combination gave rise to more than 44 different genotypes, of which 14 (31.8%) had the beta(0)/beta(0), 21 (47.7%) the beta(0)/beta(+) and nine (20.5%) the beta(+)/beta(+) types. Thus, the beta(+)-thal mutations were present in 68.2% of patients. alpha-Thalassemia mutations were present in frequencies higher than in the general population of all ethnic groups studied, as 45% of the patients carried alpha-thal mutations. Correlation of alpha-thal mutations with beta-globin mutations showed that the alpha-thal mutations were mainly co-inherited with the beta(+)-thal mutations. The XmnI (G)gamma polymorphic site at -158 (C-->T) was positive (T) in nine (8.8%) of 102 patients of the beta(+)/beta(+) genotype, and the percentage of both XmnI (G)gamma polymorphism [+/-] (T/C) and [+/+] (T/T) genotypes increased to 42.9 and 87.3, respectively, in the beta(0)/beta(+) and beta(0)/beta(0) patients. This polymorphism was found in the majority of beta(+)-thal/Hb E compound heterozygote patients (88.6%), and beta(0)-thal/Hb E patients (84.8%), suggesting that it could be linked to the Hb E chromosome. Therefore, the XmnI (G)gamma polymorphism at -158 (C-->T) was associated with beta(0)-thal mutations as well as the Hb E chromosome. The present study demonstrates that in cases of thalassemia intermedia with beta(+) mutations, the common ameliorating factor is the presence of alpha-thal mutations, while in cases with beta(0) mutations, the common ameliorating factor is the presence of the XmnI (G)gamma polymorphism at -158 (C-->T).     

The Molecular Analysis of β-Thalassemia Mutations in Lorestan Province,Iran

β-Thalassemia (thal) is one of the most common genetic disorders in Iran and other countries. Getting information on the distribution of mutations in different ethnic groups of Iran is of fundamental importance for the purpose of health planning and prenatal diagnosis programs. One hundred and thirty chromosomes from 65 unrelated homozygous β-thal patients were investigated for β‐globin gene mutations by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). The most common mutations of the Mediterranean region were examined in this study. Our results showed that the frameshift codons (FSC) 36/37 (–T) mutation, with a frequency of 33.8%, is the most common mutation in Lorestan Province. The other most frequent mutations were of the Mediterranean type and consisted of IVS-II-1 (G?→A), IVS-I-110 (G?→A), FSC 8/9 (+G) and IVS-I-5 (G?→C) with frequencies of 27.7, 11.5, 10.8 and 4.5%, respectively. The less frequent alleles, IVS-II-745 (C?→G), FSC 5 (–CT), IVS-I (25 bp deletion) and FSC 44 (–C) accounted for only 3.9% of the mutations. The unknown alleles comprised 7.7% of the mutations. These data showed that the spectrum of mutations found in Lorestan Province was different from those reported from other thalassemic regions of Iran and also of some neighboring countries.     

Molecular characterization of beta-thalassemia in the Dohuk region of Iraq

beta-Thalassemia (thal) is an important health problem in the Dohuk region of northern Iraq because of its high carrier rate and the frequency of consanguineous marriages. Thus, the need to establish an effective preventative program is paramount. As part of this effort, we initiated this study to determine the molecular basis of this disorder in the region. For the latter purpose, either parent of 104 registered beta-thal major/intermedia patients had their full blood counts, hemoglobin (Hb) electrophoresis, Hb A2 and Hb F quantitation performed. Their DNA was extracted, amplified and reverse hybridized to specific oligonucleotide probes to detect 20 beta-thal mutations. The testing detected 12 beta-thalassemic mutations. The eight most frequent were: IVS-II-1 (G-->A), codon 44 (-C), codon 5 (-CT), IVS-I-1 (G-->A), codon 39 (C-->T), IVS-I-6 (T-->C), codons 8/9 (+G) and IVS-I-5 (G-->C). These mutations accounted for 81.7% of the thalassemic defects in the studied individuals. The less frequent mutations were: codon 8 (-AA), IVS-I-110 (G-->A), codon 30 (G-->C) and codon 22 (-7 bp), and the beta-thalassemic defects remained uncharacterized in 11.5% of cases. This is the first study of beta-thal mutations from Iraq, and shows a frequency of thalassemic defects different from those reported in surrounding countries. It provides a foundation for prenatal genetic testing that will be part of a thalassemia prevention program in the Dohuk region.     

β-Thalassemia Mutations in the Kurdish Population of Northeastern Iraq

A random 123 carriers of β-thalassemia (β-thal), identified by the Sulaimaniyah Provincial Premarital Screening Program in northeastern Iraq, were screened for β-thal mutations using multiplex polymerase chain reaction followed by reverse hybridization StripAssay and direct sequencing. A total of 11 different β-thal mutations was identified in the studied samples, of which eight represented 96% of the mutated β-globin genes. These were IVS-II-1 (G>A), IVS-I-110 (G>A), codon 8 (–AA), codons 8/9 (+G), IVS-I-5 (G>C), codon 5 (–CT), IVS-I-6 (T>C) and IVS-I-1 (G>A). Other mutations were less common or sporadic. There were some notable differences in frequencies of various mutations in comparison to other eastern Mediterranean populations, as well as with previous studies of Iraqi Kurds. The latter illustrate the relative heterogeneity of the mutations distributed in Iraq, and the need to screen other areas of the country, to ensure the establishment of an effective prenatal diagnosis program.