The beta-thalassemia mutation spectrum in the Iranian population

Global distribution of β-thalassemia mutations: An update

One excellent illustration of how a single gene abnormality may result in a spectrum of disease incidence is the incredible phenotypic variety of β-thalassemia, which spans from severe anemia and transfusion needs to an utterly asymptomatic sickness. However, genetic causes of β-thalassemia and how the anemia's severity might be altered at various stages in its pathophysiology have been well investigated. There are currently known to be more than 350 mutations that cause genetic disease. However only 20 β thalassemia mutations account for more than 80% of the β thalassemia mutation across the globe due to phenomenon of geographical clustering where each population has a few common mutations together with a varying number of rare ones. Due to migration of the population, the spectrum of thalassemia mutation in changing from time to time. In this review, efforts are made to collate β globin gene mutations in different countries and populations.

Genetic Analysis of 27 Y-STR Haplotypes in 11 Iranian Ethnic Groups

BACKGROUND

The study of Y-chromosomal variations provides valuable insights into male susceptibility in certain diseases like cardiovascular disease (CVD). In this study, we analyzed paternal lineage in different Iranian ethnic groups, not only to identify developing medical etiology, but also to pave the way for gender-specific targeted strategies and personalized medicine in medical genetic research studies.

METHODS

The diversity of eleven Iranian ethnic groups was studied using 27 Y-chromosomal short tandem repeat (Y-STR) haplotypes from Y-filer® Plus kit. Analysis of molecular variance (AMOVA) based on pair-wise RST along with multidimensional scaling (MDS) calculation and Network phylogenic analysis was employed to quantify the differences between 503 unrelated individuals from each ethnicity.

RESULTS

Results from AMOVA calculation confirmed that Gilaks and Azeris showed the largest genetic distance (RST=0.35434); however, Sistanis and Lurs had the smallest considerable genetic distance (RST=0.00483) compared to other ethnicities. Although Azeris had a considerable distance from other ethnicities, they were still close to Turkmens. MDS analysis of ethnic groups gave the indication of lack of similarity between different ethnicities. Besides, network phylogenic analysis demonstrated insignificant clustering between samples.

CONCLUSION

The AMOVA analysis results explain that the close distance of Azeris and Turkmens may be the effect of male-dominant expansions across Central Asia that contributed to historical and demographics of populations in the region. Insignificant differences in network analysis could be the consequence of high mutation events that happened in the Y-STR regions over the years. Considering the ethnic group affiliations in medical research, our results provided an understanding and characterization of Iranian male population for future medical and population genetics studies.

Spectrum of Beta-Thalassemia Mutations in Potential Carriers with Microcytic Hypochromic Anemia from Mazandaran and Golestan, Northern Provinces of Iran

Introduction

β-Thalassaemia is the most common genetic disorder and is considered as a major public health concern in Iran. Different countrywide studies have shown a heterogeneous mutational basis of β-thalassaemia with different frequencies in each area. This study is aimed at investigating the common and rare mutations in Mazandaran and Golestan, northern provinces of Iran.

Methods

5425 microcytic and hypochromic individuals were investigated from Mazandaran and Golestan provinces. From these, 1323 beta carrier or affected individuals were selected where 938 persons were from Mazandaran and 385 people were from Golestan province, respectively.

Result

53 different mutations were identified, IVSII-1 (G>A) was the most common (59.14%) followed by Cd 22/23/24 (-7 bp) (5.34%), Cd 8 (-AA) (4.93%), Cd30 (G>A) (4.00%), and IVSI-5 (G>C) (3.70%) with a total of 77.11% in Mazandaran Province, respectively. In Golestan Province, IVSI-5 (G>C) was the most frequent (44.62%) followed by IVSII-1 (G>A) (27.18%), Cd 15 (TGG>TAG) (4.36%), Fr 8/9(+G) (3.85%), and Cd 8(-AA) (2.05%) with a total of 82.06%, respectively. From the 53 different mutations, 22 numbers have been observed in both provinces. Two deletions of the beta gene named Sicilian and Asian-Indian have been detected in Mazandaran with a frequency of 0.72% each.

Conclusion

The 53 different mutations identified in this study were the most ever reported mutations in the country. Due to diversity of different ethnic groups, there are many varieties of mutation in beta globin gene in Iran. It could be assumed that both founder effect and natural selection caused by migration from neighboring areas have complemented each other to produce the high frequency of unique alleles within each region.

Rare and New Mutations of B-Globin in Azari Population of Iran, a Considerable Diversity

Background

Thalassemia, as the most common single-gene genetic disorder, is related to a defect in the synthesis of one or more hemoglobin chains. More than 200 mutations have been identified in the β-globin gene. Globally, every susceptible racial group has its own specific spectrum of the common mutations that are well-known to a particular geographic region. On the other hand, varying numbers of diverse rare mutations may occur.

Materials and Methods

The subjects of the study included 2113 heterozygote or homozygote β-thalassemia cases selected among couples who participated in the Iranian national thalassemia screening program from January 2011 to November 2019. Molecular characterization of the β-thalassemia mutation was initially carried out by the amplification-refractory mutation system-polymerase chain reaction (ARMS-PCR) technique for common mutations, followed by sequencing, Gap PCR, and Multiple ligation-dependent probe amplification (MLPA) methods - in cases not detected by the ARMS-PCR.

Results

The existence of 39 rare and new point mutations and 4 large deletions were described in our cohort. Sicilian (-13,337bp) deletion, CD36/37 (-T), and CD15 TGG>TGA were encountered more often than the others in a decreasing order, in terms of frequency. The least frequent mutations/deletions were deletion from HBD exon 1 to HBB promoter, 619 bp deletion, Deletion from up HBBP1-Exon3 HBBP1 and up HBB-0.5Kb down HBB, CAP+8 C>A, CD37 (G>A), CD6 (-A), IVSI-2 (T>C), IVSII-705 T>G, and IVSII-772 (G>A). Each occurred once. Five mutations/variants were also determined which have not been reported previously in Iran.

Conclusion

According to the findings of the study, the Northwestern Iranian population displayed a wide variety of thalassemia allelic distributions. Identification of rare and new mutations in the β-thalassemia in the national population is beneficial for screening programs, genetic counseling, and prenatal diagnosis.

A decade of molecular preimplantation genetic diagnosis of 350 blastomeres for beta-thalassemia combined with HLA typing, aneuploidy screening and sex selection in Iran

Background

Preimplantation genetic diagnosis (PGD) has been developed to detect genetic disorders before pregnancy which is usually done on blastomeres biopsied from 8-cell stage embryos obtained from in vitro fertilization method (IVF).

Here we report molecular PGD results for diagnosing of beta thalassemia (beta-thal) which are usually accompanied with evaluating chromosomal aneuploidies, HLA typing and sex selection.

Methods

In this study, haplotype analysis was performed using short tandem repeats (STRs) in a multiplex nested PCR and the causative mutation was detected by Sanger sequencing.

Results

We have performed PGDs on 350 blastomeres from 55 carrier couples; 142 blastomeres for beta-thal only, 75 for beta-thal and HLA typing, 76 for beta-thal in combination with sex selection, and 57 for beta-thal and aneuploidy screening. 150 blastomeres were transferable, 15 pregnancies were happened, and 11 babies born.

We used 6 markers for beta-thal, 36 for aneuploidy screening, 32 for sex selection, and 35 for HLA typing. To our knowledge combining all these markers together and the number of STR markers are much more than any other studies which have ever done.

Conclusions

PGD is a powerful diagnostic tool for carrier couples who desire to have a healthy child and wish to avoid medical abortion.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04660-9.

Updated Molecular Spectrum of β-Thalassemia Mutations in Duhok Province, Northern Iraq: Ethnic Variation and the Impact of Immigration

Immigration impact on genetic epidemiology of thalassemia worldwide is well-recognized. Over the past decade, the Duhok Province of Northern Iraq attracted a large number of immigrants. To assess whether immigration had contributed to changes in the mutation spectrum of β-thalassemia (β-thal) in the region, we recruited 218 registered patients with symptomatic β-thal. The recruited patients included 50 (22.9%) from resettled migrant families. A total of 431 β-thal alleles were fully characterized, with 20 different thalassemia mutations, the most frequent being IVS-II-1 (G>A) (HBB: c.315 + 1G>A), IVS-I-6 (T>C) (HBB: c.92 + 6T>C), codon 5 (-CT) (HBB: c.17_18delCT), IVS-I-110 (G>A) (HBB: c.93-21G>A), codon 44 (-C) (HBB: c.135delC), codon 8 (-AA) (HBB: c.25_26delAA) and IVS-I-1 (G>A) (HBB: c.92 + 1G>A) constituting 72.8% of the total. Some differences in mutation spectrum were observed compared to earlier studies from this same province, the most notable of which were the higher frequencies of IVS-I-110 and codon 8. Interestingly, the highest proportions of alleles related to immigrants were encountered in these two allele groups. Ethnic variation was also documented, so that while Muslim Kurds had IVS-II-1, IVS-I-6, IVS-I-110, codon 5 and codon 44 as their most frequent mutations, the most frequent among Kurdish Yazidis, were codon 5, codon 44, codon 8 and IVS-I-6. These ethnic variations and changes in mutation spectrums are important and should be taken in consideration to ensure effective implementation of the thalassemia preventive program.

Following the Trace of HVS II Mitochondrial Region Within the Nine Iranian Ethnic Groups Based on Genetic Population Analysis

The Iranian gene pool is seen as an important human genetic resource for investigating the region connecting Mesopotamia and the Iranian plateau. The main objective of this study was to explore gene flow in nine Iranian ethnic/subpopulation groups (402 samples) by examining mtDNA HVS2 sequence variations. This then allowed us to detect mtDNA HVS2 sequence mutations in two independent thalassemia and cystic fibrosis patient sample groups. The patient groups did not explicitly belong to any of the aforementioned nine subpopulations. Across all subpopulations, the haplogroups B4a1c3a, H2a2a1, N10b, H2a2a2, and J1 were seen to be predominant. High haplogroup diversities along with admixture of the exotic groups were observed in this study. The Arab subpopulation was shown to be independent from the others. It was revealed that there is a far distant relationship between Arab and Azeri groups. The thalassemia patient group, represented an almost random sample of most Iranian ethnic groups, and revealed few significant differences (P < 0.05) in their HVS2 sequence. It turned out that the IVS II-I (G → A) mutation in the thalassemia β-globin gene was highly significant. Since the thalassemia patients in the present study represent many unique haplotypes, we can begin to comprehend the importance of mtDNA with this disease and the necessity for more studies in this context.

The Effect of HBB: c.-121C>T Variant [-71 (C>T)] on the β-Globin Promoter: Case Series Study

One of the effective strategies in controlling thalassemia is recognition of carriers, followed by prenatal diagnosis (PND) to prevent the occurrence of new cases. There are some rare mutations and variants, for which there are not enough evidences of their effects, and can lead to misdiagnosis and even cause confusion in decision about termination of pregnancy. That is why it is very critical to know the effect of each mutation on the β chain gene. The variant of HBB: c.-121C>T [-71 (C>T)] located in the CAAT box of the promoter region, is a rare mutation. We report seven patients in Hormozagn Province, Iran, who were referred to the PND Center of Hormozgan University of Medical Science (HUMS), Bandar Abbas, Iran during 10 years (2010-2020). Briefly, this mutation causes minor changes in blood indices [mean corpuscular volume (MCV): 75.0 ± 4.0 fL; mean corpuscular hemoglobin (MCH): 25.8 ± 2.5 pg; Hb A₂: 3.4 ± 0.5%] showed anemia with a trait milder than minor β-thalassemia (β-thal). Though the existence of α mutations (deletions/point mutations) along with HBB: c.-121C>T can change blood indices due to the changes in α/β ratio. The phenotype of β-thal intermedia (β-TI) was observed in one case, who was a compound heterozygosity for codon 15 (G>A)/-71(C>T) (HBB: c.48G>A/HBB: c.-121C>T. The analysis of transcription level by real-time polymerase chain reaction (real-time PCR) confirmed that this allele induces a mild β⁺ phenotype due to a decrease in the transcription level.

Prenatal exposure to maternal β-thalassemia minor and the risk for long-term hematologic morbidity in the offspring: A population-based cohort study

OBJECTIVE

β-Thalassemia has been shown to be associated with adverse short-term perinatal outcomes including low birth weight and preterm labor. The aim of this study was to assess whether in-utero exposure of maternal β-thalassemia minor is a risk factor for offspring hematological morbidity.

STUDY DESIGN

A population-based retrospective cohort study was conducted, including all infants born between the years 1991-2014 at a tertiary medical center. Long-term hospitalizations with hematologic morbidities were compared between offspring of mothers with or without β-thalassemia minor. Multiple gestations, perinatal mortality, chromosomal disorders and congenital malformations were excluded. Both study groups were followed until 18 years of age for hospitalization with hematological morbidities. Kaplan-Meier survival curve was used to compare the cumulative hematological morbidity incidence between both groups, and a Cox proportional hazard model was used to control for confounders.

RESULTS

During the study period, 243,682 deliveries met the inclusion criteria, of them 0.3% (n = 677) were of mothers with β-thalassemia minor. Among offspring to thalassemic versus non-thalassemic mothers, hospitalization rates involving hematological morbidity, were higher (3.3% vs. 0.7%, p < 0.001) a finding that was consistent with the Kaplan-Meier survival curve (log rank p < 0.001). Using Cox regression model, which adjusted for maternal age, SGA, gestational age and birth weight, maternal β-thalassemia minor was found to be an independent risk factor for long-term offspring hematological (aHR = 5.54; 95% CI 3.63-8.44, p < 0.001, 5.56; 95% CI 3.65-8.47, p < 0.001, and 5.49; 95% CI 3.60-8.36, p < 0.001, respectively).

CONCLUSION

Prenatal maternal β-thalassemia minor is independently associated with offspring long-term hematological morbidity.

The Spectrum of Beta-Thalassemia Mutations in Syrian Refugees and Turkish Citizens

Introduction and objectives

Neighboring the border between Turkey and Syria, Sanliurfa is one of the Turkish provinces with the highest number of Syrian refugees in our country. We aimed to find out the spectrum of beta-globin gene mutations in adult Turkish citizens and Syrian refugees with beta-thalassemia major.

Results

Of the participants, 35 patients (70%) were Turkish citizens and 15 patients (30%) were Syrian. The most common mutation in Turkish patients was found to be IVS-I-110 (G>A) with a frequency of 28.8%, followed by IVS-I-6 (T>C) with a frequency of 15.5%. Other common mutations were IVS-I-1 (G>A) and codon 39 (C>T) with frequencies of 11.1%. These four mutations accounted for 65.5% of all mutations in the Turkish cohort. The most common mutations in Syrian refugee patients were IVS-I-1 (G>A), IVS-II-1 (G>A), IVS-I-5 (G>C), and codon 5 (-CT), all with a frequency of 15.7%, accounting for 62.8% of all mutations in the Syrian patients. In the analysis, codon 5 (-CT) mutation (15.7% vs 0%, p=0.023) was found significantly higher in Syrian refugees compared to Turkish citizens.

Discussion and conclusions

A wide spectrum of mutations was detected in beta-thalassemia major patients living in the Sanliurfa region. Mutational profiles in Turkish and Syrian patients were found to be significantly different from each other. Because marriages between Syrian refugees and Turkish citizens are increasing in our region, the genetic findings and the mutational profiles in Turkish and Syrian patients obtained in this study are thought to become useful for future prenatal molecular diagnostic tests.

Presentation of two new mutations in the 3'untranslated region of the β-globin gene and evaluating the molecular spectrum of thalassemia mutations in the Mediterranean region of Turkey

Thalassemia is a common genetic disorder. We aimed to present thalassemia mutation data that covers a period of 7 years from the Mediterranean region of Turkey by comparing with hemoglobin indices and to contribute to prenatal diagnosis and genetic counseling studies which should be decided very quickly. In this study, in which a retrospective archive was scanned, the cases were first grouped as α and β thalassemia, and then β thalassemia mutations were examined in a total of 5 groups as UTR-Pro, Codon, IVS, β⁰, and β⁺. We have reached the family of the proband that analyzed their Hb indices and genetic mutation. All mutations were statistically compared with Hb indices, HbF, and HbA₂. We have identified two new β thalassemia mutations that have the feature of not being defined previously [HBB:C*62 A>G. (3'UTR+1536 A>G) and HBB:C*1 G>A (3'UTR+1475 G>A)]. The most commonly encountered 23 mutations account for 74.7% of all mutations which is unlike the literature. In the β thalassemia group, 73 different mutations were detected. The most common β thalassemia mutation was HBB: c.93-21 G>A (IVS I-110 G>A) with a frequency of 19.72%. A statistically significant difference was found when comparing the mutation groups with Hb indices. We think that it may be useful to evaluate the mutations we have newly identified too together with the Hb indices especially in evaluating the carriers of thalassemia and it will contribute to prenatal diagnosis and genetic counseling studies which should be decided very quickly.

Design and Development of Reverse Slot Blot for the Simultaneous Detection of Rare and Regional Specific Mutations in the Beta Globin Gene in Khuzestan Province of Iran

Beta-thalassemia is the most frequent hemoglobin disorder in Iran resulting from disrupting mutations in the beta globin (HBB) gene that causes decreased or complete absent of beta-globin chains. The screening of beta-thalassemia minor and major individuals and prenatal diagnosis is important for familial planning. Therefore, it is essential, depending on the ethnicity and local frequency of changes, to develop a rapid and accurate method for molecular diagnosis of beta-thalassemia. Here, we developed reverse slot blot (RSB) assay for the simultaneous detection of six common pathogenic changes in the HBB gene (-88, -28, IVSII-745, IVSII-848, Codon 6 [G → A] for HbC, Codon 6 [A → T] for HbS) in the Khuzestan Province of Iran. We designed normal and mutant oligonucleotide probes for each selected mutation and fixed them on positively charged nylon membrane. In the next step, a multiplex-polymerase chain reaction (PCR) performed for the amplification of the entire HBB gene using labelled 5'-biotinylated primers. The PCR products were hybridized to immobilized oligonucleotide probes on the membrane at the appropriate temperature. Finally, we developed the membrane by chemically colorimetric reaction using nitro-blue tetrazolium-5-Bromo-4-chloro-3-indolyl phosphate. For the best probe concentration, we made a serial dilution of probe pairs for each mutation. The optimal probe concentration for each mutation varied from 25 to 50 pmol. In the next step, DNA samples from homozygous affecting individuals were subjected for multiple PCR. Hybridization of each PCR products on the nylon membrane with probe pairs revealed specific bands with expected signal intensity without any background. Our designed RSB test is a rapid, sensitive and cost-effective method for screening of regional specific beta-thalassemia mutations in the Khuzestan population of Iran, which might be extended for the detection of any desired pathogenic changes.

Sickle Cell Disease in Jordan: The Experience of a Major Referral Center

Introduction

Sickle cell disorders are the most frequently encountered hemoglobin variants in Jordan. Both alpha and beta thalassemias are also prevalent in this population. However, studies on the interaction between these hemoglobin disorders are lacking.

Aim

To determine the genotypes responsible for Sickle cell disease in Jordan, by retrospectively reviewing the data from a major referral center in the country's capital.

Methods

A total 29,712 peripheral blood samples referred and investigated for hemoglobinopathies over a 10-year period at Princess Iman Center at Amman, Jordan were retrospectively reviewed. In addition to full blood counts, high performance liquid chromatography, those who were identified with sickle cell hemoglobin were studied using polymerase chain reaction and reverse hybridization to determine the various sickle cell disease genotypes.

Results

Out of the (29,712) blood samples, 450 were sickle cell trait, while 216 had sickle cell disease. Of the latter: 120 were found to be cases of Sickle cell anemia (Hb SS), 66 were compound heterozygous for Sickle cell and a beta thalassemia mutation (Sickle/β-thalassemia), while 30 had concomitant alpha thalassemia (HbSS/alpha thalassemia). The most frequent genotype associated with sickle/β-thalassemia was HbS/ IVS-110 (G>A), followed by Hb S/IVS-I-6 (T>C), HbS/IVS-II-745 (C>G) and HbS/ IVS-II-1 (G>A). While the most frequent alpha genotype detected in HbSS/α-thalassemia samples was (-α^3.7/αα) followed by (-α^3.7/-α^3.7). Hb SS patients had the severest hematological phenotype compared to those with sickle/β-thalassemia and sickle/ α-thalassemia. Furthermore, within the sickle/β-thalassemia subgroup the least severe hematological phenotype was encountered in HbS/IVS-1-6 (T>C), while the most severe in HbS/IVS-II-1 (G>A) genotype.

Conclusion

The most frequent Sickle cell disease genotype in Jordanians is Sickle cell anemia (HbSS), followed by Sickle/β-thalassemia and least frequent is HbSS/alpha thalassemia. The concomitant identified thalassemia mutations were consistent with their spectrum among the Jordanian population.

Genetic epidemiology of hemoglobinopathies among Iraqi Kurds

Hemoglobinopathies are major health problems among Iraqi Kurds, who are a distinct ethnic group inhabiting North and Northeastern Iraq. We reviewed published literature on these disorders in this part of the world, and it was revealed that the most prevalent is β-thalassemia with carrier rates of 3.7-6.9%. Alpha thalassemia is less prevalent with carrier rates of 0.03-1.22%, while the sickle cell gene is variably distributed with carrier rates of 0.06-1.2%. Other structural hemoglobinopathies and δβ-thalassemia are sporadic. Twenty-seven different β-thalassemia mutations were identified, with seven constituting 82% of 1039 chromosomes characterized, namely: IVS-II-1 (G>A), IVS-I-6 (T>C), IVS-I-I (G>A), codon 8 (-AA), codon 8/9 (+G), IVS-I-110 (G>A), and codon 5 (-CT). There were notable regional variations in the distribution of β-thalassemia mutations, with Cd44 being mainly prevalent in the North, while IVS-I-110 is mainly prevalent in the East. In relevance to α-thalassemia, ten different mutations were detected, with the four most frequent constituting 92.4% of 262 alleles characterized being: -α^3.7, --^MED, α^-5ntα, and α^PolyA1α. In relevance to sickle cell gene, it is seen in the northern part of the region bordering Turkey, with comparable prevalence rates, and is associated, similar to Turkey, mainly with the Benin haplotype, unlike that in Southern Iraq where it is associated with the Arab-Indian haplotype, similar to Eastern Arabian Peninsula. Given the high prevalence of hemoglobinopathies in the region, and the high rates of consanguineous marriages, a preventive program was initiated in 2008, and results of its first 5 years were promising, though there are still many outstanding challenges that require addressing.

Hepcidin gene polymorphisms and iron overload in β-thalassemia major patients refractory to iron chelating therapy

Background

β Thalassemia is one of the most common groups of hereditary haemoglobinopathies. Affected people with thalassemia major are dependent on regular blood transfusion which on the long term leads to iron overload. Hepcidin is a peptide hormone and an important regulator of iron homeostasis, especially in thalassemia. Expression of this hormone is influenced by polymorphisms within the hepcidin gene, HAMP. Several studies emphasized the role of single nucleotide polymorphisms (SNPs) located in the promoter region of the gene. This study aimed to analyze the association between three SNPs in promoter of HAMP, c.-582A > G, c.-443C > T, and c.-153C > T, with iron overload in β-thalassemia major patients.

Methods

A total of 102 samples from β thalassemia major patients were collected. Genomic DNA was extracted and segments of DNA encompassing rs10421768 and rs142126068 were sequenced. Statistical analysis was performed by SPSS Statistics 23 using independent t test and Fisher’s exact test.

Results

A total of 102 adult β-thalassemia major patients were genotyped for three SNPs in the promoter region of HAMP gene by PCR and direct sequencing. Most of the patients (71.3%) were iron overloaded (based on plasma ferritin > 1000 ng/ml) in spite of receiving regular iron-chelating therapy. Our analysis revealed a statistically significant difference between the level of cardiac iron accumulation and c.-582A > G variant (p = 0.02). For c.-443C > T statistical analysis was on the edge of the significant relationship between the minor allele and serum ferritin (p = 0.058). All samples were homozygous for allele C of c.-153C > T.

Conclusions

Despite chelating therapy, iron overload is still one of the main complications of thalassemia. Our findings and others emphasize the role of hepcidin -582A > G polymorphism as a key component of iron homeostasis in these patients.

Association between Different Polymorphic Markers and β-Thalassemia Intermedia in Central Iran

β-Thalassemia intermedia (β-TI) is a clinical condition characterized by moderate, non transfusional anemia and hepatosplenomegaly. The main objective of this study was to determine the molecular basis of the clinical phenotype of β-TI in Iran. To elucidate the mild phenotype of many patients with β-TI, we screened for three prevalent β-globin gene mutations [IVS-II-1 (G>A) HBB: c.315+1G>A, IVS-I-110 (G>A) HBB: c.93-21G>A and IVS-I-5 (G>C) [HBB: c.92+5G>C], deletions on the α-globin genes, XmnI polymorphisms and restriction fragment length polymorphism (RFLP) haplotypes on the β-globin gene cluster in 50 β-TI patients. Fifty-eight percent of the patients (29 cases) were associated with the mentioned mutations. We showed that the HBB: c.315+1G>A mutation is linked to haplotype [+ - + +] (57.69%). This haplotype is in linkage disequilibrium with the XmnI polymorphism (NG_000007.3: g.42677C>T) and has been associated with increased expression of Hb F in β-TI patients. The XmnI polymorphism is defined in association with this prevalent mutation. Two patients had a single α-globin gene deletion [-α^3.7 (rightward) deletion]. The main genetic factor in mild phenotype β-TI patients is the linkage of an XmnI polymorphism (NG_000007.3: g.42677C>T) with the HBB: c.315+1G>A (80.76%), which is associated with increased production of Hb F and coinheritance of haplotype [+ - + +] with β-TI, especially with the homozygous HBB: c.315+1G>A mutation. Molecular basis of β-TI could be explained by the involvement of different factors that tend to develop the disease phenotype.

Molecular and geographical heterogeneity of hemoglobinopathy mutations in Azerbaijanian populations

With the carrier rate of 4%-8.6%, β-thalassemia is one of the most prevalent hereditary disorders in Azerbaijan. Taking into consideration the high frequency of β-thalassemia as well as the occurrences of several other hemoglobinopathies, we conducted a large genotyping study to investigate the mutational background of common hemoglobinopathies in the country. Α- and β-globin genes were evaluated in the carriers of mutations identified via hematological indices and hemoglobin fractions (n = 1,757). Genotyping of β-thalassemia carriers identified through population screening revealed 32 mutations, with codon 8 [-AA]-34.96%, IVS-II-1 [G > A]-16.35%, and IVS-I-110 [G > A]-10.12% leading the spectrum. Analysis of associations of β-thalassemia mutations with geographical regions of the country identified the strongest association between codon 8 [-AA] and Shaki-Zaqatala, and codon 5 [-CT] in Mountainous Shirvan regions (ri > 6.00; p < 0.05). HbS, HbD-Punjab, and HbE were the most prevalent among our variant hemoglobin cohort, commonly inherited in compounds with β-thalassemia than in the homozygous state. We identified nine α-thalassemia mutations, 20.5 kb and 3.7 kb deletions together accounting for 74% of the spectrum. Point mutations of α-thalassemia were less common among our observations and were mainly inherited in compounds with deletions. Our results allow a better understanding of the wide spectrum of mutations in Azerbaijan and highlights the high heterogeneity of hemoglobinopathies in the local population.

Prevalence and Genetic Analysis of α- and β-Thalassemia and Sickle Cell Anemia in Southwest Iran

This prospective study assessed the prevalence and genetic analysis of α- and β-thalassemia and sickle cell anemia (SCA) in Southwest Iran. Hematological indices were measured in 17,581 couples living in Khuzestan Province, Southwest Iran. Individuals with mean corpuscular volume <80, mean corpuscular hemoglobin <27, hemoglobin A2 ≥3/5 were considered as β-thalassemia traits. Prevalence of minor β-thalassemia, α-thalassemia, SCA, iron deficiency anemia, and silent thalassemia were respectively identified in 995 (5.6%), 1169 (6.65%), 1240 (7.05%), 911 (5.18%), and 1134 (6.45%) individuals using a multiplex amplification refractory mutation system, and direct DNA sequencing of globin genes. Three codons IVS-II-1 (G → A; 26%; n = 13), IVS-I-1 (G → T; 16%; n = 8), and IVS-I-110 (G → A; 14%; n = 7) were the most frequent mutants and IVS-II-1 was the most common β-thalassemia mutation. Also, based on a gap-polymerase chain reaction assay, genotype frequencies of α-globin mutations were -α^{3.7 kb} (50%; n = 25), Med/αα^thal (12%; n = 6), and -α4.2/αα (10%; n = 5), which were the most frequent deletion mutants (72% in total). The most common deletion (50%) was -α^{3.7 kb}. Our data suggest that the population of Southwest Iran is at high risk of α- and β-thalassemia caused by these deletion mutants and SCA. Our findings will be useful for developing an efficient control program and genetic counseling.

Distinct genetic variation and heterogeneity of the Iranian population

Iran, despite its size, geographic location and past cultural influence, has largely been a blind spot for human population genetic studies. With only sparse genetic information on the Iranian population available, we pursued its genome-wide and geographic characterization based on 1021 samples from eleven ethnic groups. We show that Iranians, while close to neighboring populations, present distinct genetic variation consistent with long-standing genetic continuity, harbor high heterogeneity and different levels of consanguinity, fall apart into a cluster of similar groups and several admixed ones and have experienced numerous language adoption events in the past. Our findings render Iran an important source for human genetic variation in Western and Central Asia, will guide adequate study sampling and assist the interpretation of putative disease-implicated genetic variation. Given Iran's internal genetic heterogeneity, future studies will have to consider ethnic affiliations and possible admixture.

Alpha-globin gene mutation spectrum in patients with microcytic hypochromic anemia from Mazandaran Province, Iran

Background

It is estimated about 7% of the world population is carriers of hemoglobin diseases. Alpha‐thalassemia is one of the most common hereditary hemoglobin disorders in the world. This study investigated alpha‐globin mutations in potential carriers with hypochromic and microcytic anemia from Mazandaran, in northern Iran.

Methods

A total of 859 subjects were selected; genomic DNA was extracted and examined for the presence of mutations in the alpha‐globin genes.

Results

Mutation analysis of alpha‐globin genes revealed 27 different mutations. Seven variants were seen in 91.45% of all alpha‐1 and alpha‐2 mutations among patients in this study. The 3.7 kb deletion is the most frequent mutation with a frequency of 49.53%, followed by PolyA2 (15.19%), −4.2 deletion (8.76%), ‐‐MED (5.84%), IVSI‐5nt deletion (5.49%), Hb constant spring (3.62%), and Cd 19 (−G; 3.04%), respectively. There are also seven new variants which were reported for the first time either in alpha‐1 or alpha‐2 genes, including codon 9 (C > A; α2), deletion of codon 60 (AAG deletion; α2), duplication of codon 94‐100 plus 3 base pairs of intron 2 (IVSII + 3; α1), codon 99 (C > A; α2), codon 108 (A > G; α2), codon 128 (A > T; α2), and codon 129 (T > G; α2), respectively. The MLPA method also revealed three rare and novel deletions in alpha‐cluster region with about 30 kilobases long.

Conclusion

This study showed an efficient identification of α‐thalassemia can be achieved using standard hematological indices in our population. The details of these variations will help local genetic services for diagnostic and prenatal diagnosis services.

Knowledge and attitude toward genetic diseases and genetic tests among pre-marriage individuals: A cross-sectional study in northern Iran

Background

Genetic testing has been widely introduced for many hereditary disorders. While the attitudes towards these facilities have been evaluated in many countries, there are only a few reports on the knowledge of and the orientation among Iranians.

Objective

The current study assesses the attitudes and knowledge of pre-marriage individuals toward the availability and use of genetic tests.

Materials and Methods

A comprehensive questionnaire was distributed among 408 marrying individuals. The questions addressed the demographic characteristics along the registration of participant's knowledge, education, and attitude toward genetic testing. The individuals were divided into three groups based on their knowledge: 1) Scored above 80 to 100 were defined as "good" 2) 60 to 80 as "average" 3) less than 60 as "poor" knowledge.

Results

Most participants (86%) believed consanguineous marriages increase the risk of genetic diseases; 82.3% knew that thalassemia is a type of genetic disease, only 33.3% could distinguish prenatal diagnosis (PND) from other laboratory tests. The relationship between the participants' knowledge and their level of education was significant (r░=░0.78, p░<░0.001), age (r= -0.16, p░<░0.01), and urbanity (p░<░0.01). A prominent relationship was observed between the knowledge (r░=░0.64, p░<░0.001) or education (r░=░0.62, p░<░0.001) and people’s desire to use the genetic tests before the wedding ceremony. No significant correlations were found between the participant’s attitude and their ages/urbanity. Most of the individuals agreed to arrange a genetic counseling before marriage (0.94%).

Conclusion

This study revealed that most individuals were interested in using genetic counseling services and genetic tests before marriage.

The Spectrum of β-Thalassemia Mutations in Siirt Province, Southeastern Turkey

β-Thalassemia (β-thal) is the most common hereditary genetic blood disorder. The aims of this study were: (i) to determine the mutation types and the frequency of these mutations in β-thal patients to obtain the ethnic origins of the population in Siirt Province; (ii) to evaluate the pathogenicity of these mutations by performing in silico analysis; (iii) to reveal the genotype-phenotype correlation by comparing the clinical manifestation of our patients to the specific mutations in this population. This study included 34 patients (18 males and 16 females) with a mean age of 9.1 ± 3.6 years (range 3-16 years). All mutations were determined using sequence analysis methods, and the mutations were analyzed using bioinformatics tools. Thirteen different mutations were detected in the patients: IVI-I-110 (G>A) (HBB: c.93-21G>A) (38.9%); IVS-II-1 (G>A) (HBB: c.315_1G>A) (11.1%); -30 (T>A) (HBB: c.-80T>A) (9.25%) and IVS-I-1 (G>A) (HBB: c.92 + 1G>A) (9.25%), were the most common, and these mutations constituted 68.5% of the cases. Missense codon 6 (A>T) (HBB: c.20A>T) was not pathogenic; however, all the intronic mutations (IVS-I-1, IVS-I-110, IVS-II-1) and frameshift mutations [codon 44 (-C) (HBB: c.135delC) and codons 36/37 (-T) (HBB: c.112delT)] resulted in disease. These mutations can be used to determine the ethnic origin of the Siirt population and, in affected pregnant women, to develop prenatal strategies. A fatal phenotype can be identified by in silico analysis; however, mutations that are unknown prior to marriage, pregnancy, and childbirth or new mutations can be less accurately identified.

Thalassemia in the laboratory: pearls, pitfalls, and promises

Thalassemia is one of the most common hereditary disorders of the developing world, and it is associated with severe anemia and transfusion dependence. The global health burden of thalassemia has increased as a result of human mobility and migration in recent years. Depending on inherited mutations, thalassemia patients exhibit distorted hemoglobin (Hb) patterns and deviated red cell indices, both of which can be used to support identification by diagnostic tools. Diagnostic approaches vary depending on the target population and the aim of the testing. Current methods, which are based on Hb patterns, are used for first-line screening, whereas molecular testing is needed for conformation of the results and for prenatal and preimplantation genetic diagnosis. In the present paper, we review the diagnostic parameters, pitfalls, interfering factors, and methods; currently available best-practice guidelines; quality assurance and standardization of the procedures; and promising laboratory technologies for the future of thalassemia diagnosis.

Prevalence of common MEFV mutations and carrier frequencies in a large cohort of Iranian populations

Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disorder caused by mutations in the MEFV gene. The disease is especially common among Armenian, Turkish, Jewish and Middle East Arab populations. To identify the frequency and the spectrum of common MEFV mutations in different Iranian populations, we investigated a cohort of 208 unselected asymptomatic individuals and 743 FMF patients. Nine hundred and fifty-one samples were analysed for the presence of 12 MEFV mutations by PCR and reverse-hybridization (FMF StripAssay, ViennaLab, Vienna, Austria). Confirmatory dideoxy sequencing of all MEFV gene exons was performed for 39 patients. Fifty-seven (27.4%) healthy individual carried mutant MEFV alleles. Three hundred and ninety-one (52.6%) FMF patients were found positive for either one (172/743; 23.1%), two or three MEFV mutations. Using dideoxy sequencing, three novel variants, A66P, R202W and H300Q, could be identified. Our analysis revealed an allele frequency and carrier rate of 15.6 and 27.4%, respectively, among healthy Iranians. Still moderate compared to neighbouring Armenia, but higher than in Turkey or Iraq, these data suggest that FMF is remarkably common among Iranian populations. E148Q was most frequent in the group of healthy individuals, whereas M694V was the most common mutation among FMF patients, thereby corroborating previous studies on MEFV mutational spectra in the Middle East. Accordingly, MEFV mutations are frequent in healthy Iranian individuals across different ethnic groups. Based on this finding, the awareness for FMF and the implementation of augmented carrier screening programmes considering the multiethnic nature of the Iranian population should be promoted.

Molecular Characterization of β-Thalassemia Intermedia in Southeast Iran

Inheritance of mild mutations within the β-globin gene and coinheritance of α-thalassemia (α-thal) are known as two important genetic modifiers in β-thalassemia (β-thal) intermedia (β-TI). We aimed to evaluate the spectrum of β- and α-thal mutations in β-TI patients in Southeast Iran. Common β- and α-globin gene mutations were detected by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) and multiplex gap-PCR, respectively. There were 26 male (57.8%) and 19 female (42.2%) patients. HBB: c.92 + 5T > C [IVS-I-5 (G > C)] and HBB: c.-138C + 1G > A [IVS-II-I (G > A)] represented the prevalent alleles with respective frequencies of 60.0 and 10.0%. Other β-globin mutations included HBB: c.-138C > T [-88 (C > T)], HBB: c.27_28insG [frameshift codons (FSC) 8/9 (+G)], HBB: c.46delT [codon 15 (-T)], HBB: c.93-22_95del (IVS-I, 25 del), and the 619 bp deletion (NG_000007.3: g.71609_72227del619). The predominant genotypic combinations were β(0)/β(0) (68.9%), β(0)/β(+ )(8.9%) and β(+)/β(+ )(2.2%). Coinheritance of α-thal was observed in 33.0% of the patients, with the -α(3.7) (rightward) (NG_000006.1: g.34164_37967del3804) as the most common deletion (86.0%). One patient was diagnosed with the -α(4.2) (leftward) (AF221717) and one with the - -(MED) (g.24664_41064del16401) deletions, while no patients carried the -(α)(20.5) (g.15164_37864del22701), α(-5 nt) (HBA2: c.95 + 2_95_6delTGAGG) or codon 19 (-G) (HBA2: c.56delG) mutations. The alleviating molecular mechanism was not explainable by β(+ )or concurrent α-thal in more than half of our β-TI patients. This encourages conducting more studies to identify other contributing factors, especially Hb F-inducing genetic modifiers.

β-Thalassemia Haplotypes in Romania in the Context of Genetic Mixing in the Mediterranean Area

The purpose of this meta-study was to investigate β-thalassemia (β-thal) mutations and their chromosomal background in order to highlight the origin and spread of thalassemia alleles in the European and Mediterranean areas. Screening of more than 100 new Romanian β-thal alleles was also conducted. The results suggest an ancient introduction of mutations at codon 39 (C > T) (HBB: c.118C > T) and IVS-I-6 (T > C) (HBB: c.92 + 6T > C) in Romania. A comparative study was performed based on restriction fragment length polymorphism (RFLP) haplotypes associated with β-thal mutations in Romania and in Mediterranean countries. Each common β-thal allele from different populations exhibits a high degree of haplotype similarity, a sign of a clear unicentric origin for the IVS-I-110 (G > A) (HBB: c.93-21G > A), IVS-I-6, IVS-II-745 (C > G) (HBB: c.316-106C > G) and codon 39 mutations (the 17a [+ - - - - + +], 13c [ - + + - - - +], 17c [ + - - - - - +] and 14a [- + + - + + + ] ancestral RFLP background, respectively), followed by recurrent recombination events. This study also showed that geographic distances played a major role in shaping the spread of the predominant β-thal alleles, whereas no genetic boundaries were detected between broad groups of populations living in the Middle East, Europe and North Africa. The analyses revealed some discrepancies concerning Morocco and Serbia, which suggest some peculiar genetic flows. Marked variations in β(A) were observed between Southeast Asia and the Mediterranean, whereas a relative genetic homogeneity was found around the Mediterranean Basin. This homogeneity is undoubtedly the result of the high level of specific historic human migrations that occurred in this area.

Molecular Characterization of β-Thalassemia in Nineveh Province Illustrates the Relative Heterogeneity of Mutation Distributions in Northern Iraq

Beta thalassemia is an important health problem in Nineveh province, a large province in Northwestern Iraq. No previous study of significance had focused on the spectrum of β-thalassemia mutations in this part of the country. A total of 94 unrelated β-thalassemia minor subjects from the latter province were recruited. Their carrier status was confirmed by full blood count, Hb A2 and F estimation. Thereafter their DNA was subjected to multiplex polymerase chain reaction and reverse hybridization to detect 20 β-thalassemia mutations. A total of eleven different β-thalassemia mutations were documented. The most frequent mutation was IVS-I-110 (G>A) documented in 34 %, followed by IVS-I-6 (T>C) in 9.6 %, IVS-I-5(G>C) in 8.5 %, codon 39 (C>T) and codon 44 (-C) in 7.4 % each, while IVS-I-1(G>A) and IVS-II-1(G>A) were encountered in 6.4 % each. Other mutations were less frequent including codon 8 (-AA), IVS-I-130 (G>C), codon 5 (-CT) and IVS-II-745(C>G). The current study revealed notable differences in the relative frequencies of several β-thalassemia mutations in Nineveh province as compared to other parts of Northern Iraq. Such an observation may be reflective of different ethnic backgrounds and varying historical population interactions. It is believed that these findings complement those of earlier studies on β-thalassemia mutations from the country, and are quite essential in the setting of a proposed national preventive program.

Sequence and analysis of a whole genome from Kuwaiti population subgroup of Persian ancestry

Background

The 1000 Genome project paved the way for sequencing diverse human populations. New genome projects are being established to sequence underrepresented populations helping in understanding human genetic diversity. The Kuwait Genome Project an initiative to sequence individual genomes from the three subgroups of Kuwaiti population namely, Saudi Arabian tribe; “tent-dwelling” Bedouin; and Persian, attributing their ancestry to different regions in Arabian Peninsula and to modern-day Iran (West Asia). These subgroups were in line with settlement history and are confirmed by genetic studies. In this work, we report whole genome sequence of a Kuwaiti native from Persian subgroup at >37X coverage.

Results

We document 3,573,824 SNPs, 404,090 insertions/deletions, and 11,138 structural variations. Out of the reported SNPs and indels, 85,939 are novel. We identify 295 ‘loss-of-function’ and 2,314 ’deleterious’ coding variants, some of which carry homozygous genotypes in the sequenced genome; the associated phenotypes include pharmacogenomic traits such as greater triglyceride lowering ability with fenofibrate treatment, and requirement of high warfarin dosage to elicit anticoagulation response. 6,328 non-coding SNPs associate with 811 phenotype traits: in congruence with medical history of the participant for Type 2 diabetes and β-Thalassemia, and of participant’s family for migraine, 72 (of 159 known) Type 2 diabetes, 3 (of 4) β-Thalassemia, and 76 (of 169) migraine variants are seen in the genome. Intergenome comparisons based on shared disease-causing variants, positions the sequenced genome between Asian and European genomes in congruence with geographical location of the region. On comparison, bead arrays perform better than sequencing platforms in correctly calling genotypes in low-coverage sequenced genome regions however in the event of novel SNP or indel near genotype calling position can lead to false calls using bead arrays.

Conclusions

We report, for the first time, reference genome resource for the population of Persian ancestry. The resource provides a starting point for designing large-scale genetic studies in Peninsula including Kuwait, and Persian population. Such efforts on populations under-represented in global genome variation surveys help augment current knowledge on human genome diversity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1233-x) contains supplementary material, which is available to authorized users.

Broader spectrum of β-thalassemia mutations in Oman: regional distribution and comparison with neighboring countries

The objective of this study was to expand and study the molecular spectrum of β-thalassemia (β-thal) mutations in Oman by examining cases from seven different regions and comparing the prevalence with neighboring countries. A total of 446 cases of β hemoglobinopathies was obtained and analyzed to determine the frequency and distribution of the different β alleles. The molecular spectrum of β-thal in Oman revealed the presence of 32 mutations from different origins and 11 alleles are reported for the first time in the Omani population. The wide heterogeneous spectrum of β-thal mutations found can be associated with the history of trade and migration as well as the past domination from other countries. The presented data will facilitate the development of a comprehensive prevention strategy in Oman.

Hb Knossos: HBB:c.82G>T Associated with HBB:c.315+1G>A Beta Zero Mutation Causes Thalassemia Intermedia

β-thalassemia is the most common single gene disorder worldwide and in Iran. In the present study we report for the first time a rare variant of hemoglobin HBB:c.82G>T; Codon 27 GCC→TCC (Ala→Ser), Hb Knossos, using sequencing and reverse dot blot hybridization, in members of a family from North Iran. The family has a 16 years-old compound heterozygous thalassemia intermedia male child presenting this variant together with HBB:c.315+1G>A (IVSII-I) mutation. The father, heterozygous for Hb Knossos, showed borderline hematological indices. To our knowledge, this is the first report of Hb Knossos in trans with the β(O) IVSII-I allele leading to thalassemia intermedia. Our data also highlight the necessity of deep molecular characterization of subjects presenting normal HbA2 level associated with abnormal or borderline red cell indices.

Investigation of sensitivity, specificity and accuracy of Tetra primer ARMS PCR method in comparison with conventional ARMS PCR, based on sequencing technique outcomes in IVS-II-I genotyping of beta thalassemia patients

PURPOSE

Beta thalassemia is one of the most important hematic diseases all around the world and solving the problems caused by this abnormality is strongly dependent on precise detection and reliable screening of high-risk couples. The aim of our study was the investigation of sensitivity, specificity and accuracy of Tetra primer ARMS PCR method comparing with conventional ARMS PCR, based on sequencing technique outcomes for genotyping of IVS-II-I mutation in beta thalassemia patients.

METHODS

Fifty seven samples including two homozygote, 49 heterozygote and 6 normal specimens were analyzed by Tetra primer ARMS PCR and conventional ARMS PCR methods. DNA was extracted by the standard method of salting out for leukocyte genomic DNA extraction of blood specimens and a high pure PCR template preparation kit was used for DNA purification of CVS samples. The results obtained by Tetra primer ARMS PCR and conventional ARMS PCR methods were compared with gold standard technique, i.e. sequencing.

RESULTS

All three parameters including specificity, sensitivity and accuracy were 100% for Tetra primer ARMS PCR method, while they were 100%, 92.45% and 92.7% for conventional ARMS PCR technique respectively. Comparing with Tetra primer ARMS PCR which represented 100% agreement with sequencing method, conventional ARMS PCR technique only showed 47.1% agreement, because of 4 discordant results.

CONCLUSION

Tetra primer ARMS PCR method is an almost reliable, sensitive and accurate technique and it is suggested that it can be used as a complementary method for diagnostic cases instead of conventional ARMS PCR method. This suggestion originated with perfect rate of agreement between outcomes of sequencing method, as a gold standard method of detecting the mutations, and Tetra primer ARMS PCR technique comparing with conventional ARMS PCR method.

Molecular update of β-thalassemia mutations in the Syrian population: identification of rare β-thalassemia mutations

β-Thalassemia (β-thal) is an autosomal recessive disorder characterized by variable degrees of anemia, bone marrow hyperplasia, splenomegaly, and complications related to the severity of the anemic state. The β-thalassemias result from mutations in and around the β-globin gene (HBB) located as a cluster on the short arm of chromosome 11. In Syria, β-thal is highly prevalent. The main aim of this study was to identify the frequency of HBB mutations in 189 Syrian β-thal patients and carriers of β-thal. Out of the 189 patients and carriers recruited in this study, 181 patients had at least one HBB mutation and eight patients did not show any mutation. The 10 most frequent ones constituted 77.5% of all HBB mutations. These mutations in order of frequency were: IVS-I-110 (G > A) (17.0%), IVS-I-1 (G > A) (14.7%), codon 39 (C > T) (14.4%), IVS-II-1 (G > A) (9.8%), codon 8 (-AA) (6.2%), IVS-I-6 (T > C) (5.2%), IVS-I-5 (G > C) (4.9%), codon 5 (-C) (3.2%), IVS-I-5 (G > A) (3.2%) and codon 37 (G > A) (2.2%). Another 21 mutations were less frequent or sporadic. These results provide important tools for adapting a prenatal molecular diagnostic test for the Syrian population.

The diminishing trend of β-thalassemia in Southern Iran from 1997 to 2011: the impact of preventive strategies

The marginal zones of the Caspian Sea and the Persian Gulf have a higher prevalence of thalassemia compared to other regions of Iran. This disease has disabled many people and resulted in increasing health care costs. The aim of this study was to assess the incidence of β-thalassemia (β-thal) and to evaluate the outcome of applied preventive strategies over a 14-year period in Fars Province, Southern Iran. This cross-sectional study comprised all new cases of β-thal recorded during 1997-2011. The data were obtained from the Non-Communicable Diseases Surveillance Department of Shiraz University of Medical Sciences, Shiraz, Iran, and are presented as mean ± standard deviation (SD). The Fars Health Network System screened 840 686 males and females applying for marriage certificates. Among the carriers, 50.5% cancelled their marriages, 42.5% married, and 7.0% did not show up at the clinics. The rate of cancelled marriages has reduced since 2000, when marriage candidates were given the option of prenatal diagnosis. From 2000 to 2011, a total of 3539 married couples were referred for prenatal diagnosis. Of these, 806 fetuses were found to carry thalassemia and 800 aborted. It is impressive to note that while 101 cases of thalassemia were recorded in 1997, this figure was reduced to two cases by 2011. This study has established that an integrated primary health care approach, with good infrastructure for implementing successful strategies, can significantly reduce the incidence of β-thal.

Genetic epidemiology, hematological and clinical features of hemoglobinopathies in Iran

There is large variation in the molecular genetics and clinical features of hemoglobinopathies in Iran. Studying structural variants of hemoglobin demonstrated that the β-chain variants of hemoglobin S and D-Punjab are more prevalent in the Fars (southwestern Iran) and Kermanshah (western Iran) provinces, respectively. Also, α-chain variants of Hb Q-Iran and Hb Setif are prevalent in western Iran. The molecular basis and clinical severity of thalassemias are extremely heterogenous among Iranians due to the presence of multiethnic groups in the country. β-Thalassemia is more prevalent in northern and southern Iran. Among 52 different β-thalassemia mutations that have been identified among Iranian populations, IVSII-1 G:A is the most frequent mutation in most parts of the country. The presence of IVS I-5 G:C mutation with high frequency in southeastern Iran might reflect gene flow from neighboring countries. A wide spectrum of α-thalassemia alleles has been detected among Iranians with -α(3.7 kb) as the most prevalent α-thalassemia mutation. The prevention program of thalassemia birth in Iran has reduced the birth rate of homozygous β-thalassemia since the implementation of the program in 1997. In this review genetic epidemiology, clinical and hematological aspects of hemoglobinopathies, and the prevention programs of β-thalassemia in Iran will be discussed.

Sistani population: a different spectrum of β-thalassemia mutations from other ethnic groups of Iran

This study aimed to characterize the molecular spectrum of β-thalassemia (β-thal) mutations and evaluate the services available for prenatal diagnosis (PND) among the Sistani population of Iran. Mutations were analyzed with amplification refractory mutation system (ARMS), gap-polymerase chain reaction (gap-PCR), multiplex ligation-dependent probe amplification (MLPA) analysis and direct sequencing. Fetal diagnosis was also confirmed by linkage analysis. Over a 9-year period (2002-2011), 405 at-risk Sistani couples were referred for mutation analysis and/or PND. Of the referred couples, 18.5% had one to three affected children with β-thal major (β-TM) and the remainder had no children or were not married. Most of the couples (73.3%) lived in urban areas and the rate of consanguineous marriage was 76.8%. Twenty-one mutations were identified, of which the most frequent ones were IVS-I-5 (G>C) with a frequency of 74.1%, followed by codon 15 G>A (5.0%), codon -88 (C>T) (3.8%), IVS-II-1 (G>A) (3.4%), codons 8/9 (+G) (2.9%) and IVS-I-1 (G>T) (2.7%), which accounted for about 91.9% of the total β-thal mutations for this region. Furthermore, fetal DNA was obtained from chorionic villus sampling (CVS) for 266 pregnant women and 68 (25.5%) fetuses were diagnosed as affected. In summary, β-thal mutations are very heterogeneous and significantly different from those found in other parts of Iran and are similar to those of Pakistani and Indian populations. These results could greatly facilitate timely and accurate PND.

Profile of β-thalassemia and its prenatal diagnosis in Khorasan-e-Jonobi Province, Iran

This study was performed to determine the molecular spectrum of β-thalassemia (β-thal) mutations in at-risk couples from Khorasan-e-Jonobi Province in East Iran. During the past 9 years, 106 couples were referred to our Center for detection of their β-thal carrier status. Samples were initially tested for the most common Iranian α- and β-thal mutations by gap-polymerase chain reaction (gap-PCR) and amplification refractory mutation system (ARMS)-PCR, respectively. In cases with negative results, direct DNA sequencing was used to identify additional β-globin mutations. Fetal DNA was obtained from chorionic villus sampling (CVS) (n = 55), 47.2% were referred during pregnancy and 23.0% of couples underwent more than one prenatal diagnosis (PND). Of the 14 mutations that were detected in Khorasan-e-Jonobi Province, Iran, the IVS-I-5 (G>C) and codon 44 (-C) mutations were the most frequently identified variants, representing 45.9 and 24.8% of the total; these were followed by three mutations in the following order: -88 (C >T) (5.3%); codons 8/9 (+G), a rare mutation, and codons 37/38/39 [-7 nucleotides (nts)], each with a frequency of 4.5%. These findings provide complementary information on the region specific profile of β-thal in eastern Iran.

Beta-Thalassemia in Iran: new insight into the role of genetic admixture and migration

Iran with an area of 1.648 million km² is located between the Caspian Sea and the Persian Gulf. The Iranian population consists of multiethnic groups that have been influenced by various invasions and migration throughout history. Studies have revealed the presence of more than 47 different β-globin gene mutations responsible for β-Thalassemia in Iran. This paper is an attempt to study the origin of β-Thalassemia mutations in different parts of Iran. Distribution of β-Thalassemia mutations in Iran shows different patterns in different areas. β-Thalassemia mutations have been a reflection of people and area in correlation with migration and origin of ancestors. We compared the frequencies of β-globin mutations in different regions of Iran with those derived from neighboring countries. The analysis provided evidence of complementary information about the genetic admixture and migration of some mutations, as well as the remarkable genetic classification of the Iranian people and ethnic groups.

Epidemiological profile of common haemoglobinopathies in Arab countries

Haemoglobinopathies including the thalassemias and sickle cell disease are known to be prevalent inherited disorders in most Arab countries with varying prevalence rates and molecular characterisation. β-thalassemia is encountered in polymorphic frequencies in almost all Arab countries with carrier rates of 1-11 % and a varying number of mutations. The most widespread mutation in Lebanon, Egypt, Syria, Jordan, Tunisia and Algeria is the IVS-I-110 (G>A). In the Eastern Arabian Peninsula, the Asian Indian mutations (IVS-I-5 (G>C), codons 8/9 (+G) and IVS-I (-25 bp del)) are more common. The α-thalassemias are encountered in the majority of Arab countries in frequencies ranging from 1 to 58 % with the highest frequencies reported from Gulf countries. The (-α(3.7)) mutation is the most frequent followed by the non-deletional α2 polyadenylation signal mutation (AATAAA>AATAAG) and the α2 IVS1 5-bp deletion. The rates of sickle cell trait in Arab countries range from 0.3 to 30 %, with the Benin, the Arab-Indian and the Bantu haplotypes constituting the bulk of the haplotypes, leading to two major phenotypes; a mild one associated with the Arab-Indian and a severe one with the Benin and Bantu haplotypes. Public health approaches targeting prevention of haemoglobinopathies in Arab countries include newborn screening for sickle cell disease, and premarital screening for carriers of β-thalassemia and sickle cell disease. These services are still patchy and inadequate in many Arab countries recommending the upgrade of these services with strengthening of the education and training of health care providers and raising public awareness on the feasibility of prevention and care for haemoglobinopathies.

Molecular epidemiology of β-thalassemia in Pakistan: Far reaching implications

BACKGROUND:

β -Thalassaemia, an autosomal recessive hemoglobinopathy, is one of the commonest genetically transmitted disorders throughout the world. Collective measures including carrier identification, genetic counseling and prenatal diagnosis are required for preventing β-thalassemia.

Aim:

To achieve this objective, Identification of the spectrum of genetic mutations, especially for various ethnic backgrounds in Pakistan. Therefore, we designed a cross sectional prospective study to identify the frequency of various gene mutations in different ethnic groups of Pakistan.

MATERIALS AND METHODS:

Over a 5-year period, DNA from 648 blood samples {including specimens of chorionic villus sampling (CVS)} were analyzed for the twelve most common β-thalassemia mutations found in the Pakistani population by a Multiplex amplification refractory mutation system (ARMS). Each sample was analyzed for the mutation as well as the normal gene, appropriate with negative and positive controls, and reagent blanks.

RESULTS:

Out of 648 samples mutations were identified in 640 (98.75%) samples by multiplex ARMS. 8 common β-thalassemia mutations were identified in 8 different ethnic groups accounting for 93.9% of the β-thalasemia alleles.

CONCLUSIONS:

Based on the outcome of this study a cost effective proposal is formulated for detection of β-thalassemia mutations.