Updated Molecular Spectrum of ß-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 ß-thalassemia (ß-thal) in the region, we recruited 218 registered patients with symptomatic ß-thal. The recruited patients included 50 (22.9%) from resettled migrant families. A total of 431 ß-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.

Molecular characterization of glucose-6-phosphate dehydrogenase deficient variants in Baghdad city - Iraq.

BACKGROUND: Although G6PD deficiency is the most common genetically determined blood disorder among Iraqis, its molecular basis has only recently been studied among the Kurds in North Iraq, while studies focusing on Arabs in other parts of Iraq are still absent. METHODS: A total of 1810 apparently healthy adult male blood donors were randomly recruited from the national blood transfusion center in Baghdad. They were classified into G6PD deficient and non-deficient individuals based on the results of methemoglobin reduction test (MHRT), with confirmation of deficiency by subsequent enzyme assays. DNA from deficient individuals was studied using a polymerase chain reaction-Restriction fragment length polymorphism (PCR-RFLP) for four deficient molecular variants, namely G6PD Mediterranean (563 C→T), Chatham (1003 G→A), A- (202 G→A) and Aures (143 T→C). A subset of those with the Mediterranean variant, were further investigated for the 1311 (C→T) silent mutation. RESULTS: G6PD deficiency was detected in 109 of the 1810 screened male individuals (6.0%). Among 101 G6PD deficient males molecularly studied, the Mediterranean mutation was detected in 75 cases (74.3%), G6PD Chatham in 5 cases (5.0%), G6PD A- in two cases (2.0%), and G6PD Aures in none. The 1311 silent mutation was detected in 48 out of the 51 G6PD deficient males with the Mediterranean variant studied (94.1%). CONCLUSIONS: Three polymorphic variants namely: the Mediterranean, Chatham and A-, constituted more than 80% of G6PD deficient variants among males in Baghdad. Iraq. This observation is to some extent comparable to other Asian Arab countries, neighboring Turkey and Iran.

Prevalence and molecular characterization of Glucose-6-Phosphate dehydrogenase deficient variants among the Kurdish population of Northern Iraq.

BACKGROUND: Glucose-6-Phosphate dehydrogenase (G6PD) is a key enzyme of the pentose monophosphate pathway, and its deficiency is the most common inherited enzymopathy worldwide. G6PD deficiency is common among Iraqis, including those of the Kurdish ethnic group, however no study of significance has ever addressed the molecular basis of this disorder in this population. The aim of this study is to determine the prevalence of this enzymopathy and its molecular basis among Iraqi Kurds. METHODS: A total of 580 healthy male Kurdish Iraqis randomly selected from a main regional premarital screening center in Northern Iraq were screened for G6PD deficiency using methemoglobin reduction test. The results were confirmed by quantitative enzyme assay for the cases that showed G6PD deficiency. DNA analysis was performed on 115 G6PD deficient subjects, 50 from the premarital screening group and 65 unrelated Kurdish male patients with documented acute hemolytic episodes due to G6PD deficiency. Analysis was performed using polymerase chain reaction/restriction fragment length polymorphism for five deficient molecular variants, namely G6PD Mediterranean (563 C-->T), G6PD Chatham (1003 G-->A), G6PD A- (202 G-->A), G6PD Aures (143 T-->C) and G6PD Cosenza (1376 G-->C), as well as the silent 1311 (C-->T) mutation. RESULTS: Among 580 random Iraqi male Kurds, 63 (10.9%) had documented G6PD deficiency. Molecular studies performed on a total of 115 G6PD deficient males revealed that 101 (87.8%) had the G6PD Mediterranean variant and 10 (8.7%) had the G6PD Chatham variant. No cases of G6PD A-, G6PD Aures or G6PD Cosenza were identified, leaving 4 cases (3.5%) uncharacterized. Further molecular screening revealed that the silent mutation 1311 was present in 93/95 of the Mediterranean and 1/10 of the Chatham cases. CONCLUSIONS: The current study revealed a high prevalence of G6PD deficiency among Iraqi Kurdish population of Northern Iraq with most cases being due to the G6PD Mediterranean and Chatham variants. These results are similar to those reported from neighboring Iran and Turkey and to lesser extent other Mediterranean countries.

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

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

Molecular Characterization of ß-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 ß-thalassemia mutations in this part of the country. A total of 94 unrelated ß-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 ß-thalassemia mutations. A total of eleven different ß-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 ß-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 ß-thalassemia mutations from the country, and are quite essential in the setting of a proposed national preventive program.

Premarital screening for hemoglobinopathies: experience of a single center in Kurdistan, Iraq.

BACKGROUND: A program for the prevention of major hemoglobinopathies was initiated in 2008 in the Kurdistan region of Iraq. This study reports on the achievements and challenges of the program. METHODS: A total of 102,554 individuals (51,277 couples) visiting a premarital center between 2008 and 2012 were screened for carrier status of hemoglobinopathies, and at-risk couples were counseled. RESULTS: A total of 223 (4.3/1,000) couples were identified and counseled as high-risk couples. Available data on 198 high-risk couples indicated that 90.4% proceeded with their marriage plans, and 15% of these married couples decided to have prenatal diagnosis (PND) in subsequent pregnancies with the identification of 8 affected fetuses; all were terminated as chosen by the parents. Thirty affected births were recorded among the high-risk couples. The premarital program managed to reduce the affected birth rate of major hemoglobinopathies by 21.1%. Of the 136 affected babies born during the study period, 77.9% were born to couples married prior to the start of the program, while 22.1% were born to couples identified as having a high risk. The main reason for not taking the option of PND was unaffordable costs. CONCLUSIONS: Financial support would have increased opting for PND by high-risk couples. Further reduction in affected birth rates could be achieved by including parallel antenatal screening programs to cover those married before the initiation of the premarital program and improving the public health education and counseling programs.

Hepatitis C virus genotypes among multiply transfused hemoglobinopathy patients from Northern Iraq.

BACKGROUND AND AIM: Owing to the scarcity of data on hepatitis C virus (HCV) genotypes in Iraq and due to their epidemiological as well as therapy implications, this study was initiated aiming at determining these genotypes in Northern Iraq. MATERIALS AND METHODS: A total of 70 HCV antibody positive multi transfused patients with hemoglobinopathies, who had detectable HCV ribonucleic acid, were recruited for genotyping using genotype-specific nested polymerase chain reaction. RESULTS: The most frequent genotype detected was genotype 4 (52.9%) followed by 3a (17.1%), 1b (12.9%) and 1a (1.4%), while mixed genotypes (4 with either 3a or 1b) were detected in 7.1%. CONCLUSION: The predominance of genotype 4 is similar to other studies from surrounding Eastern Mediterranean Arab countries and to the only earlier study from central Iraq, however the significant high proportion of 3a and scarcity of 1a, are in contrast to the latter study and may be explainable by the differing population interactions in this part of Iraq. This study complements previous studies from Eastern Mediterranean region and demonstrates relative heterogeneity of HCV genotype distribution within Iraq and should trigger further studies in other parts of the country.