The Spectrum ofα-Thalassemia Mutations in the Kurdish Population of Northeastern Iraq

Abstract

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.

Genotype-Phenotype Correlation of HbH Disease in Northern Iraq

“…In the current study, we have identified eight different α-globin gene mutations, four of which are deletion mutations (--MED , -α 3.7 , -α 4.2 , and -(α) 20.5 ) and the remaining four are non-deletion mutations (α2 poly-A1, Hb Adana, α2 IVS1 (-5nt), and α2 poly-A2). Comparable to the results of earlier reports by Al-Allawi et al [20,21], we found the spectrum of α-globin gene defects restricted to a relatively limited number of mutations. However, this finding is unlike to what have been observed in Iran, Turkey, Sardinia, and Cyprus, where the mutations are more heterogeneous [23,24].…”

“…The carrier rate of α-thalassaemia in Iraq is estimated at < 1%, but no study has yet rectified the exact carrier rate in this region. So far, a couple of small studies by Al-Allawi et al have described the spectrum of α-globin gene mutations among carriers in the neighboring provinces of Dohuk and Sulaimaniyah [20,21]. The current study is the first to tackle a relatively large cohort of patients with HbH disease, characterized their genotypes, and correlated genotypes to patients' clinical phenotypes.…”

Alpha thalassemia allelic frequency in Lebanon

“…The polyA2 mutation was documented in 2.0% of our alpha thalassemic alleles. This has been described in Iraq: 1%; Turkey: 4%; Iran: 0.5% and was not detected in Israel, Jordan, UAE, Saudi Arabia, Algeria, and Oman (Table ). Anti‐3.7 triplication, a sporadic mutation, without any hematological sign unless associated with beta globin mutation was detected in only one of our patients, with an allele frequency of 1% which is similar to the Iranian population of the Kerman province (26%) and lower than that reported in Israel (3.2%) .…”

Molecular spectrum of α-globin gene mutations in the Aegean region of Turkey: first observation of three α-globin gene mutations in the Turkish population

“…--MED mutation seems to be specific to Mediterranean areas. It has been reported among the first three or four most frequent mutations in Mediterranean and Middle Eastern populations whereas it has not to been seen in Far Eastern populations [7,16,17,19,20,24,26].…”