Identification of HBC [ß6(a3)GLU→LYS] in a thai Male

Abstract

The propositus was a 29-year-old Thai male, whose electrophoretic pattern showed Hb A (58% plus an abnormal hemoglobin (42% with mobility identical to Hb A2and Hb E. Protein sequencer analysis and tryptic peptide mapping of the ß chain indicated that the abnormal hemoglobin was Hb C [ß6(A3)Glu→Lys], rather than Hb E which is more commonly found in South East Asia. This conclusion was confirmed by direct sequence analysis of the propositus' DNA, which showed AAG as well as GAG at codon 6 of the ß gene, in agreement with heterozygosity for Hb C and Hb A. Furthermore, the ß gene framework (Ava II -, Bam HI + of the propositus suggested that the ßcgene may have arisen from an independent mutation. Since Hb C and Hb E have the same mutation (Glu→Lys) in the ß chain, although at different positions, and behave similarly in electrophoresis, cases of Hb C and Hb E may sometimes have been mistakenly identified for each other, based on whichever variant is most prevalent in the particular population. © 1993 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.