title: The molecular basis of Hb H disease in Turkey.
abstract: 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.
authors.affiliation: Department of Molecular Biology, Hacettepe University Science Faculty, Beytepe, Ankara, Turkey.
authors.forename: C
authors.initials: C
authors.lastname: Oner
authors.forename: A
authors.initials: A
authors.lastname: Gürgey
authors.forename: R
authors.initials: R
authors.lastname: Oner
authors.forename: H
authors.initials: H
authors.lastname: Balkan
authors.forename: F
authors.initials: F
authors.lastname: Gümrük
authors.forename: E
authors.initials: E
authors.lastname: Baysal
authors.forename: C
authors.initials: C
authors.lastname: Altay
mesh_terms: 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
chemical_list: D006447:Hemoglobin H