Sickle Cell Disease in the Kurdish Population of Northern Iraq

Abstract

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 β-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 β- and α-thalassemia (β- and α-thal) mutations, whenever indicated. Results showed that the most common genotype was sickle cell anemia (68.0%) followed by Hb S/β(0)-thal and Hb S/β(+)-thal at frequencies of 24.2 and 7.8%, respectively. Eight β-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' β-globin gene cluster haplotyping of 128 β(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.

Presence of the IVS-I-6-Mutated Allele in Beta-Thalassemia Major Patients Correlates with Extramedullary Hematopoiesis Incidence

“…The IVS-I-6 (T→C) mutation is one of the most common causes of β-thalassemia among individuals of Mediterranean and Middle Eastern ancestry [39,40]. Its high incidence has been reported among populations from Portugal [41]; Spain [42,43]; Albania [44]; the region of former Yugoslavia [45,46,47,48]; Greece [49,50,51,52]; Algeria [53]; Egypt [54]; Palestine [55,56]; Lebanon [57]; Syria [58,59]; Cyprus [60]; Turkey [61,62,63,64,65]; Saudi Arabia [66,67]; Iraq [68,69,70,71]; Iran [72,73,74]; and elsewhere. It results from a base substitution close to the 5′ splice junction, between exon I and intron I, and within a conserved consensus sequence, interfering with mRNA splicing and, consequently, reducing its efficiency.…”

Doppler-Defined Pulmonary Hypertension in Sickle Cell Anemia in Kurdistan, Iraq

“…In the latter part of Iraq, most cases are registered in a single center in the Kurdish province of Duhok, where the frequency of the sickle cell gene is 1.2% [10], with around 236 registered SCA patients and a comparable number of Sickle/β-thalassemia syndromes at the only care center dedicated to their care. Despite such significant number of registered sickle cell disease patients in the latter center and the reported high prevalence of PH in SCA in the literature with its associated increased mortality rate, studies addressing its frequency, associated risks and mortality rates in our patients have not yet been initiated.…”

The first five years of a preventive programme for haemoglobinopathies in Northeastern Iraq

“…2,[5][6][7] Sickle cell disorders were seen mainly in the extreme north and south of the country, with the highest carrier rates in the south reaching up to16% in some localities. 8,9 Such high carrier rates coupled with around a 30% rate of consanguineous marriages, 10 and the limited resources available to the health services, make initiating a preventive programme for these disorders a necessity. 11 A prevention programme based to a great extent on the Cypriot model 12 (premarital screening, genetic counselling and prenatal diagnosis [PND]) was initiated in northern Iraq in 2008, following pilot studies to determine the service indicators for prevention and defining the molecular basis of b-thalassaemia in the region.…”