ABSTRACT
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.
Subject(s)
Black People , Fetal Hemoglobin/genetics , Thalassemia/genetics , Alleles , Chromosome Mapping , DNA Restriction Enzymes , Erythrocyte Indices , Female , Gene Frequency , Genotype , Heterozygote , Humans , Male , Pedigree , Thalassemia/bloodSubject(s)
Hemoglobins, Abnormal/analysis , Adult , Aged , Amino Acid Sequence , Amino Acids/blood , Female , Fetal Blood , Humans , Infant, Newborn , Male , Middle AgedABSTRACT
High pressure liquid chromatography (HPLC) has been used for the detection and quantitation of the beta chain variants Hb S and Hb C in blood samples of newborn babies with different hemoglobinopathies. The complete separation of the Hbs C, S, A, and F made it possible to diagnose conditions such as AS AC, SS, CC, SC and even S(C)-beta+ thalassemia. The procedure is fast (62 min) and ideally suited for the quantitation of Hb F at birth. Data for a few hundred cord blood samples indicate a great variability in the relative quantities of Hb S or Hb C in heterozygotes which prevents a definitive diagnosis of a simultaneously occurring alpha-thalassemia except perhaps of the homozygous form of alpha-thalassemia-2 (alpha o alpha/alpha o alpha). The large spread in the data also shows some overlap between the quantitative results in Hb S (or Hb C) heterozygotes and in babies with the Hb S (Hb C)-beta-thalassemia condition.
Subject(s)
Fetal Hemoglobin/analysis , Hemoglobin A/analysis , Hemoglobin C/analysis , Hemoglobin, Sickle/analysis , Hemoglobinopathies/blood , Infant, Newborn, Diseases/blood , Chromatography, High Pressure Liquid/methods , Fetal Blood/analysis , Heterozygote , Humans , Infant, NewbornABSTRACT
A survey of nearly 250,000 citizens of Georgia and South Carolina conducted during the past twenty years has led to the detection of over 40 abnormal hemoglobins and several additional hemoglobinopathies. The presence of some of these hemoglobin abnormalities cause (severe) clinical symptoms but others remain undetected unless a specific search is initiated. The incidence of Hb S varies slightly among the populations of different areas, and appears to be the highest in the coastal counties of Georgia and South Carolina. A survey of over 17,000 persons of mainly high school and college age has shown that a significant number of cases with clinically significant hemoglobinopathies will remain undetected unless such surveys are actively promoted.