HB T-CAMBODIA, A BETA-CHAIN VARIANT WITH THE MUTATIONS OF HB-E AND HBD-PUNJAB, CONFIRMED BY DNA ANALYSIS

Hemoglobin variants with two amino acid substitutions affecting one gl obin chain are relatively rare. Hb T-Cambodia, a doubly substituted be ta-globin variant, was characterized. previously by amino acid sequenc ing as having sequence alterations in beta 26(beta 8)Glu-->Lys and bet a 121(GH4)Glu-->Gln (1). It is a variant that migrates cathodic to Hb A(2) on alkaline electrophoresis and with Hb A on acid citrate agar el ectrophoresis. We report here the mutations of Hb T-Cambodia at the nu cleotide level using DNA sequencing, in beta-globin gene codon 121 (GA A-->CAA) and in codon 26 (GAG-->AAG). These are the mutations of Hb D- Punjab and Hb E, respectively.