We have determined the alpha-thalassaemia (alpha-thal) determinants in 78 patients with Hb H disease from Cyprus ; 25 were Turkish Cypriots and 53 were Greek Cypriots.
Four deletional and three non-deletional alpha-thal alleles were present ; the - alpha (3-7 kb) alpha-thal-2 and the - - MED-1alpha-thal-1 were most frequently seen ; - - MED-II and - (alpha) 20.5 deletions occurred at considerably lower frequencies.
About 15% of all chromosomes carried a non-deletional alpha-thal-2 allele ; of these the 5 nucleotide (nt) deletion at the first intervening sequence (IVS-I) donor splice site was present in ~8% of all chromosomes.
Two types of polyadenylation signal (poly A) mutations were observed.
No striking frequency differences were seen between Greek and Turkish Cypriot patients.
Combinations of the various types of alpha-thal resulted in eight different forms of Hb H disease.
The phenotypes were comparable except for great variations in the level of Hb H which was highest (average ~22%) in the 12 patients with the alpha5nta/--MED-I combination.
One patient with the same corm of Hb H disease but with an additional bêta-thal (IVS-I-110, G-A) heterozygosity had a most severe microcytosis and hypochromia with<1% Hb H. Variations in the level of Hb H might correlate with the severity of the disease, although this was not evident from the haematological data.
Mots-clés Pascal : Thalassémie alpha, Hémoglobine H, Homme, Ethnie, Epidémiologie, Déterminisme génétique, Exploration, Délétion, Allèle, Chypre, Asie, Hémopathie, Anémie hémolytique, Hémoglobinopathie, Maladie héréditaire, Aberration chromosomique, Chromosome anormal
Mots-clés Pascal anglais : alpha-Thalassemia, Hemoglobin H, Human, Ethnic group, Epidemiology, Genetic inheritance, Exploration, Deletion, Allele, Cyprus, Asia, Hemopathy, Hemolytic anemia, Hemoglobinopathy, Genetic disease, Chromosomal aberration, Abnormal chromosome
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 95-0240674
Code Inist : 002B19A01. Création : 09/06/1995.