The molecular basis of Hb H disease in Turkey.
A total of 25 unrelated Hb H patients were studied at the DNA level. Ten different genotypes were found to be responsible for the disease. The most prevalent alpha-thalassemia-2 determinant was the alpha alpha/-alpha (3.7) kb deletion (56%) which was followed by a nondeletional type of alpha-thalassemia, namely the pentanucleotide deletion in the 5' first intervening sequence splice junction [alpha(-5nt) alpha] (16%). The two most frequent alpha-thalassemia-1 determinants were alpha alpha/-20.5 kb and alpha alpha/-17.5 kb (MED-I) deletions. In two patients, homozygosity for the polyadenylation signal mutation [alpha (PA-2)alpha] was found to be responsible for Hb H disease. Clinical and hematological expression seems more severe in patients with the alpha (-5nt) alpha deletion at the donor site of the first intervening sequence and the alpha(PA-2) alpha mutation in trans to an alpha-thalassemia-1 determinant. Homozygosity for the alpha (PA-2)alpha mutation was also found to be associated with severe phenotype.
Oner
C
C
Department of Molecular Biology, Hacettepe University Science Faculty, Beytepe, Ankara, Turkey.
Gürgey
A
A
Oner
R
R
Balkan
H
H
Gümrük
F
F
Baysal
E
E
Altay
C
C
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006403:Hematologic Tests; D006447:Hemoglobin H / Q000235:genetics*; D006801:Humans; D008297:Male; D010641:Phenotype; D014421:Turkey
D006447:Hemoglobin H