Abstract
Members of a Black family from Georgia who were investigated for the first time in 1960 (Ref. 2) and several times thereafter (Refs. 8,19,20) were reinvesti-gated through DNA restriction endonuclease analyses and haplotyping, while the γ chain heterogeneity of the Hb F was reevaluated using a newly developed HPLC procedure. Four different abnormalities were present, (a) Heterozygosity for GγAγ−HPFH type II characterized by a large deletion involving the δ and β globin genes with a 5′ end within the ψβ gene. (b) Heterozygosity for an -ϵ-Gγ-Gγ-ψβ-δ-βS-chromosome, thus carrying a βS globin gene and two Gγ genes instead of one Gγ and one Aγgene. (c) Heterozygosity for an -ϵ-Gγ-Aγ-T-ψβ-δ-βS-chromosome, carrying the βS globin gene and an allele of the aγ (or aγI) gene. These three chromosomes occurred in combination with each other, resulting in SS and S-HPFH conditions, and with a normal -ϵ-Gβ-Aβ-ψβ-δ-βA-chromosome resulting in the HPFH and Hb S het-erozygosities. The presence of the -Gγ-Gγ- and -Gγ-AγT-chromosomes in the one SS patient was resonsible for the high Gγ value (average 75%), 25% aγT chain, and for the absence of the AγI chain. (d) An α-thalasse-mia-2 heterozygosity in one member.