. 2012 Dec 8;4(2):147–167. doi: 10.1007/s12687-012-0127-8

Table 4.

Spectrum of α-thalassemia gene mutations in Arab countries

Country	Most frequent α-thalassemia gene mutations (reference)
Algeria	Among 153 blood donors screened for 10 α-thalassemic determinants: 2.9 % had the (−α^3.7), 0.6 % the α2 initiation codon T>C (α^Nco1α), and the (α^−5ntα), (−(α)^20.5) and (− −^MED-1) at 0.3 % each (Mesbah-Amroun et al. 2008)
Bahrain	Among 97 α-thalassemia chromosomes, the most common was the (α ^{poly A1}α) (53 %), followed by (− α^3.7) (32 %), (α^−5ntα) (12 %), (− α^4.2) (2 %) and (α ^{poly A2}α) (1 %). The cause of HbH disease is consistently (α^{poly A1}α/α^{poly A1}α), other genotypes are rare (Jassim et al. 2001)
Bahrain	Among 410 umbilical cord blood samples, 9.5 % were identified as α thalassaemia. The percentage of the different genotypes detected was: 4.5 % for (−α/αα), 3 % for (−α/–α), 1.75 % for (− −/αα) and 0.25 % HbH disease (− −/− α). No cases of Hb Bart’s hydrops fetalis (− −/− −) were detected (Rizk et al. 2005)
Iraq	Among 51 individuals with unexplained hypochromia and/or microcytosis from the Dohuk region in northern Iraq, 51 % had the (−α^3.7/αα), 23.5 % the (− −^MED-I/α α), 9.8 % the (−α ^3.7/–α ^3.7) and 3.9 % the (−α^4.2/αα), other genotypes were sporadic . On the other hand, all 9 HbH cases studied had the (−α^3.7/− −^MED-I) genotype (Al-Allawi et al. 2009)
Jordan	Among 430 α-thalassemic patients investigated: 43 % had the (−α^3,7), followed by the (α^polyA1α) in 31 %, the (α^−5ntα) and the (− −^MED-I) in 18 % and 7 % respectively. Among 33 patients with HbH disease 60.6 %, 15.1 %, 12.2 % and 12.2 % had the (α ^{poly A1}α/α^{poly A1}α), (α^{poly A1}α/− −^MED-I), (−α^3.7/− −^MED-I) and (α^−5ntα/− −^MED-I), respectively (Abu-Ghoush 2008)
Kuwait	Among 17 HbH patients 70.8 % had the (α^{poly A1}α/α^{poly A1}α), while 25 % had the (α^{poly A1}α/–α^3.7)and 4.2 % were undetermined (Haider and Adekile 2005)
Kuwait	Of the 30 chromosomes from 15 patients with HbH disease, 86.7 % carried the (α^polyA1α), 10 % had (−α^3.7), and 3.3 % had the (α^−5ntα) (Adekile et al. 1994)
Saudi Arabia	Among 41 patients suffering from microcytic, hypochromic anemia from the eastern province, the most common alpha determinant was the (−α^3.7) in 64 % followed by the (α^{poly A1}α) in 41 % (Hellani et al. 2009)
	A study to determine the deletional forms of α-thalassemia revealed that the (−α/αα) varied between 9.6 and 38.8 %, while the (−α/–α) ranged from 5 to 12.7 % in various regions of the kingdom (El-Hazmi and Warsy 1999)
	In Eastern region, it was found that 45 % carried the (−α^3.7), while another 15 % had a non-deletional defect (αα^T), later found to be (α^polyA1α) (Al-Awamy 2000; Higgs et al. 1983)
Tunisia	No α⁰-thal alleles were found among 304 blood samples. Among cord blood samples from northeastern region, the (−α^3.7) was the most common defect (4.5 % allele frequency) followed by (α^{poly A1}α) in 1.8 %, while (α^−5ntα) and the (−α^4.2) in 0.9 % each (Zorai et al. 2002)
Tunisia	Testing 20 index cases with Hb Barts at birth revealed that 35 % had the (−α^3.7/αα), 25 % had the (α^−5ntα/αα), 5 % (−α^3.7/−α^3.7), while α^cd23^GAG>stop, α^cd119CCT>TCT and α^+6C>G were carried by 5 % each. In 7 families with HbH: 5 had the genotype (α^{poly A1}α/α^{poly A1}α), two had the (−α^3.7/− −^MED-I) (Siala et al. 2008)
UAE	Among 418 consecutive cord blood samples: 33.5 % were (−α^3.7/αα), 11 % were (−α^3.7/−α^3.7), 1.4 % (α^−5ntα/αα), 1.2 % (−α^4.2/αα), 0.7 % each for (α^polyA1α/αα) and (α^CSα/αα). Other sporadic mutations included (α^polyA2α/αα). In 22 patients with HbH disease or HbH-like syndrome, 9 were (α^polyA1α/−α^3.7), 6 were homozygous for the (α^polyA1α) mutation, 2 were homozygous for Hb CS, and 5 were compound heterozygous for either (α^polyA1α), (α^CSα), (α^−5ntα), or (− −^MED-I), with the (−α^3.7) (El-Kalla and Baysal 1998; Haj Khelil et al. 2010)