title: Dysfunctional alpha-globin genes in hemoglobin H disease in blacks: variation in restriction fragment size permits the detection of the -alpha/-alpha T genotype.
abstract: Hemoglobin H (HbH) disease is most often due to deletion of three of the four alpha-globin genes (genotype --/--alpha). In black subjects although the -alpha/chromosome is common, the --/haplotype is very rare and few examples of HbH disease have been detected. We have studied three black siblings with HbH by restriction endonuclease mapping of the alpha-like gene complex (5'-zeta-psi zeta-psi alpha 2-psi alpha 1-alpha 2-alpha 1-3') using zeta- and alpha- specific probes. The presence of size differences in the previously described hypervariable region between the zeta and psi zeta genes results in a restriction fragment length polymorphism which permitted the detection of single alpha genes on both number 16 chromosomes in these subjects. Quantitative DNA hybridization by a slot-blot technique confirmed that their genomes contained two alpha-globin genes. The results establish that in these black subjects HbH disease is associated with dysfunctional alpha-globin genes (genotype: -alpha/-alpha T).
mesh_terms: D044383:Black People; D002872:Chromosome Deletion; D005838:Genotype; D005914:Globins / Q000235:genetics*; D006801:Humans; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length; D013789:Thalassemia / Q000175:diagnosis / Q000235:genetics*
chemical_list: D005914:Globins