Distribution of beta-thalassemia mutations in the northern provinces of Iran

Beta-Thalassemia (thal) is one of the most common autosomal recessive disorders in Iran. There are more than two million carriers of beta-thal and over 15,000 people affected with beta-thal major who live in Iran. Prevalent mutations were identified by examining genomic DNAs isolated from 392 blood samples of beta-thal carriers from three northern provinces of Iran. Furthermore, 172 pregnant women were analyzed from the 196 couples who requested pregnant diagnosis for beta-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 (GA), is followed, in order of frequency, by codon 30 (GC), frameshift codons (FSC) 8,9 (+G), FSC 22/23/24 (-AAGTTGG), IVS-I-110 (GA), IVS-I-5 (GC), IVS-II-745 (CG), IVS-I-2 (TC), FSC 8 (-AA), IVS-I,3'-end (-25 bp), IVS-I-1 (GA), FSC 36/37 (-T), IVS-I-6 (TC), FSC 5 (-CT), -28 (AC), codon 37 (GA), IVS-II-2,3 (+11/-2), -30 (TA), and -88 (CA). 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.     

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.     

An unusually frequent beta-thalassemia mutation in an Iranian Province

Iran, a country located on the "thalassemia belt", is an area with an unusually high prevalence of beta-thalassemia (thal). The gene frequency of thalassemia shows great variation within Iran from one area to another. The purpose of this study was to determine the spectrum of beta-thal mutations in Sistan-Baluchestan (S-B), a southeastern province of Iran which has a high mutation frequency of about 10%, and to compare this with neighboring provinces and countries. A total of 400 carriers (200 pre-marriage young couples selected at centers conducting prenatal diagnosis programs) with an established diagnosis of beta-thal minor, were enrolled into the study. Mutations in the beta-globin gene were detected using amplification refractory mutation system (ARMS) and restriction fraction length polymorphism (RFLP). Three hundred and sixty mutant chromosomes (13 different mutations) were detected with the two most common mutations accounting for about 80% of all detected beta-thal alleles in this region. The most common mutation by far was IVS-I-5 (G>C) (72.3%), followed by frameshift codons (FSC) 8/9 (+G) (5.8%) and codon 44 (-C) (2.5%). In conclusion, IVS-I-5 and FSC 8/9 (+G) account for about 80% of all mutations in S-B. Sistan-Baluchestan may be regarded as the 'hot zone' for the IVS-I-5 mutation.     

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     

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.     

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.     

β-Thalassemia Mutations in the Iranian Kurdish Population of Kurdistan and West Azerbaijan Provinces

The aim of this study was to investigate the prevalence and spectrum of β-thalassemia (β-thal) mutations in the population of Sunni Muslim Kurds in western Iran and to set up a prenatal diagnostic laboratory. Sixty unrelated Kurdish β-thal patients identified in hematology clinics from different cities were studied. The mutations in 120 chromosomes were studied by polymerase chain reaction–amplification refractory mutation system and direct sequencing methods. We found fifteen β-thal mutations, and IVS-II-1 (G>A) was the most frequent, comprising 35%?of all mutations. Other common mutations were frameshift codons 8/9 (+G) 15.7%, IVS-I-1 (G>A) 8%, FSC 5 (–CT) 6.7%, FSC 8 (–AA) 6.7%, and IVS-I-110 (G>A) 6%. This is the first comprehensive study in this region and could provide a reference for prenatal testing and genetic counseling in this population.     

An Unusually Frequent β-Thalassemia Mutation in an Iranian Province

Iran, a country located on the “thalassemia belt”, is an area with an unusually high prevalence of β-thalassemia (thal). The gene frequency of thalassemia shows great variation within Iran from one area to another. The purpose of this study was to determine the spectrum of β-thal mutations in Sistan-Baluchestan (S-B), a southeastern province of Iran which has a high mutation frequency of about 10%, and to compare this with neighboring provinces and countries. A total of 400 carriers (200 pre-marriage young couples selected at centers conducting prenatal diagnosis programs) with an established diagnosis of β-thal minor, were enrolled into the study. Mutations in the β-globin gene were detected using amplification refractory mutation system (ARMS) and restriction fraction length polymorphism (RFLP). Three hundred and sixty mutant chromosomes (13 different mutations) were detected with the two most common mutations accounting for about 80% of all detected β-thal alleles in this region. The most common mutation by far was IVS-I-5 (G>C) (72.3%), followed by frameshift codons (FSC) 8/9 (+G) (5.8%) and codon 44 (?C) (2.5%). In conclusion, IVS-I-5 and FSC 8/9 (+G) account for about 80% of all mutations in S-B. Sistan-Baluchestan may be regarded as the ‘hot zone’ for the IVS-I-5 mutation.     

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.     

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.     

The beta-thalassemia mutation spectrum in the Iranian population

Beta-thalassemia is the most common hereditary disease in Iran. More than two million carriers of beta-thalassemia live in Iran. Since the Iranian population is a mixture of different ethnic groups, it is necessary to determine the frequency and distribution of mutations in the different parts of the country. For this purpose, we divided Iran in to eight different regions according to the geographic and ethnic distribution of the population. Over a 10-year period 1,217 beta-thalassemia chromosomes of 164 affected patients and 889 unrelated carriers were studied using the amplification refractory mutation system-polymerase chain reaction technique. We detected 81% beta-thalassemia mutations in the studied chromosomes. IVS-II-I (G --> A) was the predominant mutation found in our study (34%). Its relative frequency in the north was much higher than other regions, and it lessened toward the south, where the IVS-I-5 (G --> C) mutation was more common. IVS-I-5 (G --> C) (7.55%), codons 8/9 (+ G) (4.76%), and IVS-I-110 (G --> A) (4.76%) were the other most common mutations. The results presented here can be used as a basis of prenatal diagnosis of beta-thalassemia in different regions of Iran.     

Contribution to the description of the beta-thalassemia spectrum in Tunisia and the origin of mutation diversity

We determined the spectrum of beta-thalassemia (thal) mutations in 118 affected unrelated patients with different forms of beta-thal. Using a combination of reverse dot-blot analysis, denaturing gradient gel electrophoresis (DGGE), polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) and direct nucleotide sequencing, we identified the largest spectrum of beta-thal mutations so far reported in Tunisia, and to the best of our knowledge, within the Mediterranean Basin. A total of 18 distinct alleles were detected at different frequencies, with two alleles [codon 39 (C-->T) and IVS-I-110 (G-->A)] predominating all others. Seven other alleles [frameshift at codon (FSC) 6 (-A), FSC 8 (-AA), codon 30 (G-->C), IVS-I-1 (G-->A), IVS-I-2 (T-->G), IVS-I-6 (T-->C), FSC 44 (-C)] were rare, and nine alleles [-29 (A-->G), IVS-I-2 (T-->C), IVS-I-5 (G-->C), IVS-I-5 (G-->T), IVS-I-116 (T-->G), codon 37 (G-->A), IVS-II-1 (G-->A), IVS-II-745 (G-->C) and IVS-II-849 (A-->C)], albeit described elsewhere, are reported here in Tunisia for the first time. The codon 39 and IVS-I-110 mutations were the two predominant alleles occurring at frequencies of 43.8% and 10.8%, respectively. They are presumably the earliest mutations introduced into this country. The codon 39 allele could have been introduced in Tunisia during the Roman occupation. Similarly, the IVS-I-110 mutation might have been introduced by the Turkish and Phoenician influence. Both gene flow and private mutations may account for the diversity of alleles observed in Tunisia. These data provide the background for implementing prevention programs based on genetic counseling and prenatal diagnosis.     

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.     

Analysis of beta-thalassemia mutations in northern Thailand using an automated fluorescence DNA sequencing technique

A total of 218 beta-thalassemia (thal) genes from 109 beta-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 beta-globin promoter region which have not been reported in Thailand before [-31 (A --> G) and -87 (C --> A)]. Although these mutations are described as beta+-thal, the compound heterozygote with one of the common beta(o)-thal mutations exhibits the phenotype of beta-thal major. The frequency of beta-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 beta-globin gene mutations from this study will be useful for planning a prenatal diagnosis program especially for this region of Thailand.     

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.     

The beta-thalassemia mutation/haplotype distribution in the moroccan population

The present study compiles the results of our own research and of a prior study on beta-thalassemia (thal) in Morocco, comprising a total of 187 beta-thalassemic chromosomes. Six major mutations: (beta0) codon 39 (C --> T), (beta+) IVS-I-6 (T --> C), (beta0) frameshift codon (FSC) 6 (-A), (beta0) FSC 8 (-AA), (beta0) IVS-I-1 (G --> A) and (beta+) -29 (A --> G) account for 75.7% of the independent chromosomes studied. A regional predominance was observed (Gharb and West regions) for the (beta+) IVS-I-6 (T --> C) mutation. Despite an observed heterogeneity of molecular anomalies, a direct method of diagnosis of the prevalent mutations is feasible in this population. The distributions of mutations and haplotypes are in conformity with the geographical location of Morocco and the historical links with both the Mediterranean communities that have successively interspersed with the Berbers, the Phoenicians, the Carthaginians, the Romans, the Arabs, the population of the Iberian Peninsula and, to a lesser degree, the Vandals and the Byzantines and permanently, with the Sub-Saharan Africans. In the adult population, the levels of fetal hemoglobin (Hb) in heterozygotes vary from trace quantities to 2.38 g/dL of total Hb. With the exception of the (beta0) codon 39 (C --> T) nonsense mutation, no statistically significant correlation was found, neither between mutation and Hb F levels, nor gender and Hb F levels in heterozygotes. The genetic markers for Hb F increase, located within cis active sites such as the XmnI site at -158 bp of the Ggamma-globin gene and the AT(X)T(Y) repeat region at -540 bp of the beta-globin gene, were assessed. The polymorphism XmnI shows linkage disequilibrium with haplotypes III, IV and IX, as previously observed in the Algerian, Sicilian and Portuguese beta-thal populations. Contrary to what has previously been reported for a population of beta-thal carriers of European descent, this sample does not show a statistically significant correlation between Hb F levels and the presence of the genetic markers XmnI restriction site at -158 bp of the Ggamma-globin gene and AT(X)T(Y) alleles at 5' of the beta-globin gene.     

The molecular pathology of beta-thalassemia in Turkey: the Boğaziçi university experience

The thalassemias are a diverse group of hemoglobin (Hb) disorders characterized by a reduced synthesis of the globin chains of Hb. Today, more than 200 mutations, affecting different levels of beta-globin gene expression, by a variety of mechanisms, are known to result in a beta-thalassemia (thal) phenotype. According to recent findings, the multilayered complexity in the phenotype of beta-thal is the result not only of marked molecular heterogeneity at the beta-globin locus, but at the level of several other genes as well. The heterogeneity at the beta-globin locus, which is the most reliable and predictive factor of disease phenotype, is simplified, to a certain extent, by the fact that the mutations are ethnic-group specific. Fifty out of >200 beta-thal mutations account for 90-95% beta-thalassemias worldwide. In the broad group of Mediterranean countries, approximately 35 mutations have been reported thus far; however, allele frequencies vary among countries. beta-Thal is a major public health concern in Turkey; throughout the country the gene frequency is estimated to be 2.1%, but in certain regions, this figure increases to 10%. The estimated number of carriers is 1,300,000 and the number of homozygous beta-thal patients is around 4,000. The number of affected births is higher than expected, since the birthrate is still very high in Turkey, and the number of consanguineous marriages is above 60% in the eastern parts of the country. Unlike many other Mediterranean countries, beta-thal in Turkey is very heterogeneous at the clinical level, transfusion-dependent beta-thal major predominating. Between 1987 and 2006, more than 1,500 patients with homozyous beta-thal, unrelated and not preselected, were investigated by DNA analysis. Our results revealed that by far the most common mutation in Turkey is IVS-I-110 (G-->A), followed by IVS-I-6 (T-->C) and frameshift codon (FSC) 8 (-AA). The six most common mutations add up to approximately 70.3%, and the overall frequency of the first 12 mutations is 83.3%. The ratio of beta (0):beta (+)-thal mutations is 1:1, but the majority of beta (+)-thal cases carry the severe IVS-I-110 lesion; thus, most of these mutations give rise to beta-thal major in homozygous or compound heterozygous combinations. In addition to the 12 common mutations, several rare and four novel beta-thal mutations were reported in the framework of this project, totaling 36 mutations. Turkey's large molecular heterogeneity can be explained by its unique geographical position and rich history, an important crossroad between cultures, civilizations and continents for several centuries. This study shows that despite its great molecular heterogeneity, and with the advent of polymerase chain reaction (PCR)-based techniques and improved methods of early fetal sampling, heterozygote screening and prenatal diagnosis are feasible in Turkey.     

Population-Based Genetic Study of β-Thalassemia Mutations in Mardan Division,Khyber Pakhtunkhwa Province,Pakistan

β-Thalassemia (β-thal) is the most prevalent hereditary blood disorder in Pakistan with a carrier rate of 5.0–8.0%. The homozygous affected children require frequent blood transfusions for their survival. This autosomal recessive disease can only be prevented through awareness programs, carrier screening, mutation detection, genetic counseling and prenatal diagnosis (PND). The present study aimed to determine the prevalence of various mutations causing β-thal and also to detect carriers of these mutations in families living in the Mardan Division, Khyber Pakhtunkhwa (KP) Province, Pakistan. The study was conducted at the Department of Biochemistry, Abdul Wali Khan University Mardan, Pakistan. Blood samples of β-thalassemic families were collected from various transfusion centers in Mardan Division. Using the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) technique, all samples were analyzed for the six most common mutations causing β-thal in this area. Six different mutant primers for the detection of different mutations were used. The most common mutations detected in thalassemic patients were frameshift codons (FSC) 8/9 (+G) (HBB: c.27_28insG), codons 41/42 (–TTCT) (HBB: c.126_129delCTTT), and IVS-I-5 (G>C) (HBB: c.92+5G>C). The predominant mutation for carrying the mutant genes for β-thal were FSC 8/9, IVS-I-5, codons 41/42, IVS-I-1. It was also found that 66.7% of marriages were consanguineous. The FSC 8/9 mutation was found to be the most common β-thal mutation with a frequency of 44.4%. This research project provides a strong incentive for the establishment of large scale mutation detection and PND services in the Mardan Division.     

β-THALASSEMIA INTERMEDIA FROM SOUTHERN IRAN: IVS-II-1 (G→A) IS THE PREVALENT THALASSEMIA INTERMEDIA ALLELE

The preliminary results of a pilot study are reported, intended as an initiation of a research plan, focused on the prevention of β-thalassemia in Iran. The aims of this study are: (i) to improve the knowledge of the molecular background of β-thalassemia intermedia in Southern Iran; (ii) to verify the role of the ?158 ^Gγ (C→T) (Xmn I) polymorphism as a modulating factor in thalassemia intermedia; (iii) to test the validity of the multiplex and single mutation specific amplification refractory mutation system in analyzing the molecular defects causing β-thalassemia in multiethnic populations; and (iv) to develop suitable strategies for the application of prevention protocols in Iran. To accomplish the task we have selected 87 β-thalassemia intermedia patients and adapted the DNA methodology to detect the following 11 frequent mutations in Iran: codon 5 (?CT); frameshift codons (FSC) 8/9 (+G); codon 30 (G→C); IVS-I-1 (G→A); IVS-I-5 (G→C); IVS-I-6 (T→C); IVS-I-110 (G→A); codons 36/37 (?T); codon 44 (?C); IVS-II-1 (G→A); IVS-II-745 (C→G). Because of the multiethnicity of the population we have also included the Indian IVS-I (25?bp deletion) and the Mediterranean IVS-I-130 (G→C) and codon 39 (C→T) mutations. Forty-eight patients were randomly studied for the Xmn I polymorphism together with 50 healthy volunteers as a control group. The molecular analysis conducted in Iran, identified only 31% of the alleles that were presumed to be thalassemic, revealing either a strategic or a technical insufficiency of the chosen method. However, the mutations with the highest prevalence in the country (IVS-II-1, IVS-I-110, IVS-I-1 and FSC 8/9) were found. As expected the IVS-II-1 defect, being the most frequent in south Iran, was present at the highest rate (24%). The Xmn I polymorphism was found in association with this prevalent mutation and was detected in the homozygous state in 87.5% of the patients homozygous for the IVS-II-1 (G→A) mutation. The overall positivity for Xmn I was found in 40.6% of the thalassemic alleles vs. 14% in the non-thalassemic, confirming the hypothesis of an older event, antecedent to the IVS-II-1 mutation. In trying to assess a more suitable molecular detection method we intend to continue this study in collaboration with the European centers involved, applying more effective technologies and better defining the molecular spectrum of β-thalassemia in the sub-populations. We also intend to verify the effect of α-thalassemia in the genotype/phenotype correlation of β-thalassemia intermedia.     

Identification of Three Novel Mutations [−41 (A>C), codon 24 (–G), and IVS-I-109 (−T)], in a Study of β-Thalassemia Alleles in the Isfahan Region of Iran

β-Thalassemia (β-thal) is one of the most common autosomal recessive disorders in Iran, with more than 15,000 registered cases of thalassemia major in the country. Iran has a multiethnic society and knowledge of the mutation spectrum and regional distribution is an essential requirement for health planning and a prenatal diagnosis program. We have determined the spectrum of mutations in patients from the Isfahan region of Iran. A study of 190 chromosomes revealed 24 different mutations, including three novel ones: ?41 (A>C), IVS-I-109 (–T) and codon 24 (–G). The most common mutation was IVS-II-1 (G>A) (20.5%), followed by IVS-I-5 (G>C) (11%). The findings for the Isfahan region confirm the extremely heterogeneous nature of the molecular basis of β-thal in Iran. The results show that a strategy of using the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) for 14 of the most common mutations and DNA sequencing for the rare mutations can be used for prenatal diagnosis of β-thal in this region.