Molecular characterization of alpha-thalassemia in the Dohuk region of Iraq.
The molecular basis of alpha-thalassemia (alpha-thal) has been addressed by several studies from the eastern Mediterranean region, but not from Iraq. To address this issue, we studied 51 individuals with unexplained hypochromia and/or microcytosis, as well as nine patients with documented Hb H disease from the Dohuk region in northern Iraq. We used multiplex gap-polymerase chain reaction (gap-PCR), reverse hybridization, and sequencing for this purpose. It was found that the most common genotypes in those with unexplained hypochromia and/or microcytosis were -alpha(3.7)/alpha alpha, followed by - -(MED-I)/alpha alpha, then -alpha(3.7)/-alpha (3.7), respectively, detected in 84.3% of the above individuals. Other genotypes identified sporadically were -alpha(4.2)/alpha alpha, alpha(poly A1)alpha/alpha alpha (AATAAA>AATAAG), alpha(Adana)alpha/alpha alpha [Hb Adana, codon 59 (Gly-->Asp) or HBA1:c.179G>A], and alpha(Evanston)alpha/alpha alpha [Hb Evanston, codon 14 (Trp-->Arg) or HBA1:c.43 T>C]. Three cases (5.88%) remained uncharacterized even after sequencing. All nine Hb H cases carried the -alpha(3.7)/- -(MED-I) genotype. Such findings are rather different from those in other eastern Mediterranean populations, particularly with relevance to an Hb H molecular basis.
Al-Allawi
Nasir A S
NA
Department of Pathology, College of Medicine, University of Dohuk, Dohuk, Iraq. nallawi@yahoo.com
Badi
Ameer I A
AI
Imanian
Hasham
H
Nikzat
Nooshin
N
Jubrael
Jaladet M S
JM
Najmabadi
Hossein
H
D000747:Anemia, Hypochromic / Q000235:genetics; D004252:DNA Mutational Analysis; D005838:Genotype; D006801:Humans; D007493:Iraq / Q000453:epidemiology; D017085:alpha-Thalassemia / Q000453:epidemiology / Q000235:genetics*