Homozygosity for a New Type of ^Gγ(^Aγδβ)°-Thalassemia in a Malaysian Male

Abstract

Hematological and clinical data are presented for a young Malay patient with a homozygous (δβ)°-thalas- semic condition. His red blood cells contained 1007% fetal hemoglobin with α and ^Gγ chains only. Detailed gene mapping defined a large deletion with a 5' end between the Aha III and Apa I sites, some 200–400 bp 5' to the ^Aγ globin gene and a 3' end beyond sequences 17–18 kb 3' to the β globin gene. This ^Gγ(^Aγδβ)°-type of thalassemia is different from all the other six types described before. Comparison of the hematological data of this patient with those of homozygotes for either the Sicilian or Spanish types of ^Gγ^Aγ(δβ)°-thalassemia showed no differences; all homozygotes have a moderate anemia which is accentuated by the relatively high oxygen affinity of the Hb F containing erythrocytes.