A Population-Oriented Genetic Scoring System to Predict Phenotype: A Pathway to Personalized Medicine in Iraqis With ß-Thalassemia.

To assess the roles of genetic modifiers in Iraqi ß-thalassemia patients, and determine whether a genotype-based scoring system could be used to predict phenotype, a total of 224 Iraqi patients with molecularly characterized homozygous or compound heterozygous ß-thalassemia were further investigated for α-thalassemia deletions as well as five polymorphisms namely: rs7482144 C > T at HBG2, rs1427407 G > T and rs10189857 A > G at BCL11A, and rs28384513 A > C and rs9399137 T > C at HMIP. The enrolled patients had a median age of 14 years, with 96 males and 128 females. They included 144 thalassemia major, and 80 thalassemia intermedia patients. Multivariate logistic regression analysis revealed that a model including sex and four of these genetic modifiers, namely: ß+ alleles, HBG2 rs7482144, α-thalassemia deletions, and BCL11A rs1427407 could significantly predict phenotype (major versus intermedia) with an overall accuracy of 83.9%. Furthermore, a log odds genetic score based on these significant predictors had a highly significant area under curve of 0.917 (95% CI 0.882-0.953). This study underscores the notion that genetic scoring systems should be tailored to populations in question, since genetic modifiers (and/or their relative weight) vary between populations. The population-oriented genetic scoring system created by the current study to predict ß-thalassemia phenotype among Iraqis may pave the way to personalized medicine in this patient's group.

Beta Globin Gene Cluster Haplotypes in Beta Thalassemia in the Kurdistan Region of Iraq.

ß-thalassemia is a prevalent inherited red cell disorder in the Kurdistan region of Iraq. To determine the chromosomal background of the frequent ß-thalassemia mutations in the latter region, we investigated the ß-globin gene cluster haplotypes in 202 ß-thalassemia chromosomes. Haplotypes analysis utilized restriction fragment length polymorphism-PCR of seven restriction sites through the ß-globin gene cluster. It was observed that IVS-II-1 (G > A) was mainly associated with haplotype III (68.8%), IVS-1-110 (G > A), codon 8/9 (+G) and codon 44 (-C) with haplotype I (in 90.0%, 100%, and 62.5% respectively), IVS-1-6 (T > C) with haplotype VI (97.4%), codon 8 (-AA) with haplotype IV (75%), codon 5(-CT) and IVS1.1 (G > A) with haplotype V (55.6% and 58.3% respectively), while codon 39 (C > T) and IVS1.5 (G > C) were mainly associated with haplotype VII (85.7% and 75% respectively). These observations support the notion that while some mutations may have originated in the Kurdistan region, others were more likely brought in by gene flow from neighboring countries or the Indian subcontinent. The association of some ß-thalassemia defects with more than one haplotype may be due to mutations or recombination events.

Silent Cerebral Infarcts in Iraqi Patients with Sickle Cell Disease.

Silent ischemic infarcts have been reported to be the most frequent neurological abnormalities in sickle cell disease (SCD) in several studies worldwide. However, no previous studies investigated this neurological disorder in Iraqi SCD patients. To address this issue, a total of 52 patients with a median age of 20 years (range 10-46) and including 46.2% males were enrolled. Patients were clinically evaluated and their records were reviewed. They had full blood and reticulocyte counts, hemoglobin F estimation, serum lactic dehydrogenase and bilirubin assayed, as well as brain magnetic resonance imaging (MRI) to screen for silent cerebral infarcts. Six out of the 52 patients (11.5%) had silent cerebral infarcts, all of which were in the deep white matter, ranging from 6 to 10 mm in their largest diameters. There were no significant differences in age, sex, or sickle cell genotype between those with silent cerebral infarcts and those without it. Those with silent cerebral infarcts had lower median hemoglobin, higher reticulocytes and lower pain frequencies than those without it, yet again this was not significant. Follow up MRI in four out of the six silent infarct patients showed no additional lesions and no increase in size of the original ones after six to eight months. In conclusion, it appears that the frequency of silent cerebral infarcts in Iraqi SCD patients is lower than the bulk of the literature from other populations. Further studies to screen for genetic polymorphisms that may explain this lower rate may be informative.

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.

A Novel ß0-Thalassemia Mutation, HBB: c.356_357delTT [Codon 118 (-TT)] in an Iraqi Kurd.

We report a novel frameshift ß-thalassemia (ß-thal) mutation due to a two-nucleotide deletion at codon 118 of the ß-globin gene (HBB: c.356_357delTT) in a 4-year-old Iraqi Kurd female presenting as transfusion-dependent ß-thal. This frameshift mutation, unlike many others involving the third exon, behaved as a recessive ß0 defect and not as dominant ß-thal mutation.

CYP2C19 Genotype is an Independent Predictor of Adverse Cardiovascular Outcome in Iraqi Patients on Clopidogrel After Percutaneous Coronary Intervention.

To determine the impact of CYP2C19 genotyping on the occurrence of major adverse cardiovascular events (MACE), in cohort of Iraqi patients on clopidogrel after percutaneous coronary intervention (PCI), a total of 201 Iraqi patients undergoing the latter procedure were enrolled. All enrollees had their CYP2C19 genotyped using polymerase chain reaction and reverse hybridization. Genotyping revealed that CYP2C19 *1, *17, *2, and *8 allele frequencies were, respectively, 0.604, 0.276, 0.117, and 0.0026. After the exclusion of those with 2 loss of function alleles, 186 patients were available for follow-up as long as they were on clopidogrel, or until MACE occurred, which was encountered in 8.6% after a median of 12 months. Among predictors associated with MACE was the carriage of one CYP2C19 loss of function allele {hazard ratio (HR) 8.6 [confidence interval (CI) 3.15-23.4]; P < 0.0005}, hypertension [HR 3.74 (CI 1.06-13.16); P = 0.04], reduced ventricular function [HR 3.88 (1.43-10.54); P = 0.008], and history of previous myocardial infarction [HR 4.9 (CI 1.48-11.33); P = 0.007] by univariate analysis, although only CYP2C19 genotype remained significant by multivariate analysis [HR 11.88 (CI 3.25-43.44); P < 0.0005]. The latter observation favors CYP2C19 genotype-guided antiplatelet therapy and extending the use of alternative antiplatelet drugs to those with single loss of function allele after percutaneous coronary intervention.

The genetic basis of asymptomatic codon 8 frame-shift (HBB:c25_26delAA) ß(0) -thalassaemia homozygotes.

Two 21-year old dizygotic twin men of Iraqi descent were homozygous for HBB codon 8, deletion of two nucleotides (-AA) frame-shift ß(0) -thalassaemia mutation (FSC8; HBB:c25_26delAA). Both were clinically well, had splenomegaly, and were never transfused. They had mild microcytic anaemia (Hb 120-130 g/l) and 98% of their haemoglobin was fetal haemoglobin (HbF). Both were carriers of Hph α-thalassaemia mutation. On the three major HbF quantitative trait loci (QTL), the twins were homozygous for G>A HBG2 Xmn1 site at single nucleotide polymorphism (SNP) rs7482144, homozygous for 3-bp deletion HBS1L-MYB intergenic polymorphism (HMIP) at rs66650371, and heterozygous for the A>C BCL11A intron 2 polymorphism at rs766432. These findings were compared with those found in 22 other FSC8 homozygote patients: four presented with thalassaemia intermedia phenotype, and 18 were transfusion dependent. The inheritance of homozygosity for HMIP 3-bp deletion at rs66650371 and heterozygosity for Hph α-thalassaemia mutation was found in the twins and not found in any of the other 22 patients. Further studies are needed to uncover likely additional genetic variants that could contribute to the exceptionally high HbF levels and mild phenotype in these twins.

Predictors of Red Cell Alloimmunization in Kurdish Multi Transfused Patients with Hemoglobinopathies in Iraq.

Hemoglobinopathies are significant health problems in Iraq, including its Northern Kurdistan region. One of the essential components of management of these disorders is regular lifelong blood transfusions. The latter is associated with several complications including red cell alloimmunization. No study has looked at the frequency of alloimmunization and its associations in the country. To address the latter issue, 401 multi transfused patients [311 with ß-thalassemia (ß-thal) syndrome and 90 with sickle cell disease], registered at a large thalassemia care center in Iraqi Kurdistan had their records reviewed, and their sera tested for atypical antibodies using screening and extended red cell panels. Red cell alloimmunization was detected in 18 patients (4.5%) with a total of 20 alloantibodies, while no autoantibodies were detected. The most frequent alloantibody was anti-E, followed by anti-D, anti-K, anti-C(w), anti-C, anti-c and anti-Le(a). Ethnicity was an important predictor of alloimmunization, while age at start of transfusion (>2 vs. ≤2 years) (p = 0.005), Rhesus D (RhD) negative status (p = 0.0017) and history of previous transfusion reactions (p = 0.007) showed a statistically significant higher rate of alloimmunization. However, patients' age, gender, number of units transfused, underlying diagnosis and splenectomy were not significantly associated with alloimmunization. Based on our observations, measures to reduce alloimmunization rates may include extended matching for Rhesus and Kell antigens and early initiation of blood transfusions.

Molecular Basis of ß-Thalassemia Intermedia in Erbil Province of Iraqi Kurdistan.

ß-Thalassemia intermedia (ß-TI) is a clinical term describing a range of clinical phenotypes that are intermediate in severity between the carrier state and ß-thalassemia major (ß-TM). To characterize the molecular basis of ß-TI in Erbil Province, Northern Iraq, 83 unrelated patients were investigated. Detection of ß-globin gene mutations was carried out by reverse hybridization assay and direct gene sequencing. All patients were screened for the XmnI polymorphism by direct sequencing of HBG2 ((G)γ promoter gene). Detection of α-globin gene deletions and triplication was carried out using the reverse hybridization assay. Four main molecular patterns were identified in association with the ß-TI phenotype, namely: ß(+)/ß(+) (38.5%), ß(+)/ß(0) (21.6%), ß(0)/ß(0) (31.3%), and ß(0)/wild type (8.4%). IVS-I-6 (T > C) was the most frequently encountered mutation (55 alleles, 34.6%), followed by IVS-II-1 (G > A) and codon 8 (-AA); furthermore, we report for the first time from Iraq two ß(+) mutations, -87 (C > G) and 5' untranslated region (5'UTR) +22 (G > A). The XmnI polymorphism was detected in 47.0% of patients, mainly in association with the ß(0)/ß(0) genotype. The α-globin gene deletions were encountered in four cases, including one case with (- -(FIL)) double gene deletion, a report that is the first from our country. The α-globin gene triplication was detected in five of the seven heterozygous ß-thalassemia (ß-thal) patients. Similar to other Mediterranean countries, inheritance of mild ß-globin mutations was the main molecular pattern underlying ß-TI in our patients followed by the ameliorating effect of the XmnI polymorphism.

Diagnostic exome sequencing to elucidate the genetic basis of likely recessive disorders in consanguineous families.

Rare, atypical, and undiagnosed autosomal-recessive disorders frequently occur in the offspring of consanguineous couples. Current routine diagnostic genetic tests fail to establish a diagnosis in many cases. We employed exome sequencing to identify the underlying molecular defects in patients with unresolved but putatively autosomal-recessive disorders in consanguineous families and postulated that the pathogenic variants would reside within homozygous regions. Fifty consanguineous families participated in the study, with a wide spectrum of clinical phenotypes suggestive of autosomal-recessive inheritance, but with no definitive molecular diagnosis. DNA samples from the patient(s), unaffected sibling(s), and the parents were genotyped with a 720K SNP array. Exome sequencing and array CGH (comparative genomic hybridization) were then performed on one affected individual per family. High-confidence pathogenic variants were found in homozygosity in known disease-causing genes in 18 families (36%) (one by array CGH and 17 by exome sequencing), accounting for the clinical phenotype in whole or in part. In the remainder of the families, no causative variant in a known pathogenic gene was identified. Our study shows that exome sequencing, in addition to being a powerful diagnostic tool, promises to rapidly expand our knowledge of rare genetic Mendelian disorders and can be used to establish more detailed causative links between mutant genotypes and clinical phenotypes.

Recessive thrombocytopenia likely due to a homozygous pathogenic variant in the FYB gene: case report.

BACKGROUND: Inherited thrombocytopenias (IT) are a heterogeneous group of rare diseases characterized by a reduced number of blood platelets. The frequency of IT is probably underestimated because of diagnostic difficulties and because not all the existing forms have as yet been identified, with some patients remaining without a definitive diagnosis. Exome Sequencing has made possible the identification of almost all variants in the coding regions of protein-coding genes, thereby providing the opportunity to identify the disease causing gene in a number of patients with indefinite diagnoses, specifically in consanguineous families. CASE PRESENTATION: Familial thrombocytopenia with small size platelets was present in several members of a highly consanguineous family from Northern Iraq. Genotyping of all affected, their unaffected siblings and parents, followed by exome sequencing revealed a strong candidate loss of function variant in a homozygous state: a frameshift mutation in the FYB gene. The protein encoded by this gene is known to be a cytosolic adaptor molecule expressed by T, natural killer (NK), myeloid cells and platelets, and is involved in platelet activation and controls the expression of interleukin-2. Knock-out mice were reported to show isolated thrombocytopenia. CONCLUSION: Inherited thrombocytopenias differ in their presentation, associated features, and molecular etiologies. An accurate diagnosis is needed to provide appropriate management as well as counseling for the individuals and their family members. Exome sequencing may become a first diagnostic tool to identify the molecular basis of undiagnosed familial IT. In this report, the clinical evaluation combined with the power and efficiency of genomic analysis defined the FYB gene as the possible underlying cause of autosomal recessive thrombocytopenia with small platelet size. This is the first report linking pathogenic variants in FYB and thrombocytopenia in humans.

The spectrum of α-thalassemia mutations in the Kurdish population of Northeastern Iraq.

In an attempt to determine the spectrum of α-thalassemia (α-thal) mutations in the Kurdish population of Northeastern (NE) Iraq, a total of 101 unrelated adults with unexplained hypochromia and/or microcytosis were enrolled. α-Thalasssemia mutations were characterized by gap polymerase chain reaction (gap-PCR), multiplex PCR (m-PCR) and reverse hybridization and sequencing for both α genes. A total of nine α-thal mutations were characterized including four deletional ones: -α(3.7) (rightward), - -(MED-I), -(α)(20.5), -α(4.2) (leftward) and five nondeletional ones: α(polyA1)α, αα(Adana), α(-5 nt)α, α(CS)α and α(polyA2)α. These determinants were arranged in 12 different genotypes, the most frequent of which were: -α(3.7)/αα, - -(MED-I)/αα, -α(3.7)/-α(3.7), α(polyA1)α/αα, αα(Adana)/αα and -(α)(20.5)/αα. This pattern is similar to that reported in Turkey, western (W) Iran, Cyprus and Greece, and to some extent, different from the pattern observed in the Arabian Peninsula.

The spectrum of ß-thalassemia mutations in Baghdad, Central Iraq.

While previous studies from Iraq have focused on ß-thalassemia (ß-thal) mutations in the northern part of the country, inhabited mainly by Kurds, no study of significance has looked at these mutations in central or southern Iraq, which is inhabited by the Arab majority. For the latter purpose this study was initiated and 103 ß-thal carriers from Baghdad at the center of the country were investigated using multiplex polymerase chain reaction (PCR) and reverse hybridization followed by sequencing. The results revealed that a total of 17 mutations were implicated, six of which, IVS-I-110 (G>A), IVS-II-1 (G>A), IVS-I-5 (G>C), codons 8/9 (+G), IVS-I-I (G>A) and codon 44 (-C), constituted 78.0% of the mutations characterized. Among the 17 mutations identified, six are reported for the first time from Iraq and include: IVS-I, 25 bp deletion, IVS-II-848 (C>A), -28 (A>C), IVS-I-130 (G>C), IVS-I-128 (T>G) and codons 41/42 (-TTCT). The findings of the current study clearly illustrate the genetic heterogeneity of the population of central Iraq, as demonstrated by the presence of a combination of Mediterranean, Asian Indian, Kurdish, Iranian, Egyptian, Saudi Arabian and Turkish mutations that is reflective of the historical background of this part of the country.

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.

Sickle cell disease in the Kurdish population of northern Iraq.

Epidemiological studies have revealed that sickle cell disease patients are clustered in two geographical areas in Iraq, one among the Arabs in the extreme south, another among the Kurdish population in the extreme north, where they constitute major health problems. However, no studies have focused on the genotypes responsible for sickle cell disease or the ß-globin gene haplotypes associated with it. For the latter purpose, a total of 103 unrelated Kurdish sickle cell disease patients were evaluated by restriction fragment length polymorphism (RFLP) for the sickle cell mutation, followed by multiplex polymerase chain reaction (PCR) and reverse hybridization for ß- and α-thalassemia (ß- and α-thal) mutations, whenever indicated. Results showed that the most common genotype was sickle cell anemia (68.0%) followed by Hb S/ß(0)-thal and Hb S/ß(+)-thal at frequencies of 24.2 and 7.8%, respectively. Eight ß-thal mutations were associated with the latter two genotypes including: IVS-II-1 (G>A), IVS-I-110 (G>A), codon 8 (-AA), codon 44 (-C), codon 22 (-7 bp), IVS-I-1 (G>A), codon 30 (G>C) and IVS-I-6 (T>C). In Hb SS patients, the -α(3.7) deletion was documented in 10.0% and was the only α-thal mutation detected. Furthermore, 5' ß-globin gene cluster haplotyping of 128 ß(S) chromosomes revealed that the most common haplotype seen in 69.5% was the Benin haplotype, followed by the Arab-Indian haplotype in 12.5%. These latter findings closely resemble reports from neighboring Turkey, Syria, Jordan, Lebanon and Mediterranean countries, suggesting a possible common origin, but are in contrast to findings from the Eastern Arabian Peninsula and Iran.

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 ß-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 δß-thalassemia are sporadic. Twenty-seven different ß-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 ß-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: -α3.7, --MED, α-5ntα, and αPolyA1α. 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.

The Outcome of Acute Lymphoblastic Leukemia in 109 Adult Iraqi Patients.

While many studies addressed the outcome of adult ALL in developed Western countries, there is paucity of such prospective studies from developing Mediterranean ones. This is a prospective cohort study conducted at Hiwa Cancer Hospital in Sulaimani city and Nanakali Hospital in Erbil city-Kurdistan Iraq from March 2012 to August 2017. The main characteristics of adult ALL patients, type of therapy and risk factors were analyzed to assess their impact on treatment outcome and survival status. A total of 109 adult ALL patients were included with a median age of 24 years and male to female ratio of 1.7:1. B-ALL accounted for 76.1% of the cases, while the rest were T-ALL. BCR-ABL rearrangement was encountered in 12% of B-ALL. Complete remission (CR) rate was 81.7%, the overall 5 year survival (OS) was 38%, Relapse Free 5 year Survival (RFS) was 49%. Younger adults (< 35 years) had significantly higher CR rates and OS compared to the older group (P < 0.001 each). On the other hand, gender, high leucocyte count ≥ 50×109/L, immunophenotype (including B and T ALL subtypes), and clinical risk status did not predict a poor outcome. Multivariate analysis revealed that only age < 35 years and BCR-ABL rearrangement were significantly associated with better OS. Despite some limitations, the outcomes of Iraqi adult ALL is comparable to those reported in Western developed countries, with particularly favorable outcomes in younger patients. The need to improve outcome in adult ALL remains an important priority in our country as it is throughout the world.

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.

ß-Thalassemia mutations in the Kurdish population of northeastern Iraq.

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