Five haplotypes in Black beta-thalassaemia heterozygotes: three are associated with high and two with low G gamma values in fetal haemoglobin.
Genotypes at seven different polymorphic restriction sites (5' to the epsilon gene, at the G gamma, at the A gamma, at the psi beta, 3' to the psi beta, at the beta, and 3' to the beta genes) were analysed by restriction endonuclease mapping of the DNA from 66 Black beta-thalassaemia heterozygotes from Georgia and several of their normal relatives. Five different haplotypes were observed. Three of these were associated with high G gamma values in the small amount of Hb F (0.8-8.3%) present in the blood of these patients and two with low G gamma values. One haplotype [- + - + + + +] that occurred on two of every three beta thalassaemia chromosomes was associated with high G gamma levels, and is the same as that found in some Black SS patients also having high G gamma values (Gilman & Huisman, 1984). Two others [- + + - + - +] and [- + - - + + +] were also associated with high G gamma, while two [- - - - + + +] and [+ - - - - + +] were associated with low G gamma. Variation in haematological data, mainly MCV and MCH values, was found to be caused in part by the type of beta-thalassaemia (defined by its haplotype) and by the presence of an additional alpha-thalassaemia-2 heterozygosity or homozygosity.
Harano
T
T
Reese
A L
AL
Ryan
R
R
Abraham
B L
BL
Huisman
T H
TH
D000483:Alleles; D044383:Black People; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes; D004909:Erythrocyte Indices; D005260:Female; D005319:Fetal Hemoglobin / Q000235:genetics*; D005787:Gene Frequency; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D010375:Pedigree; D013789:Thalassemia / Q000097:blood / Q000235:genetics*
D005319:Fetal Hemoglobin; D004262:DNA Restriction Enzymes