Hemoglobin variants in which a frameshift results in chain elongation are unusual and also have a low population frequency. Hb Tak was previously characterized by amino acid analysis, and it was assumed to be due to an insertion of the dinucleotide CA into codon 146 [CAC→CA(CA)C] which abolishes the normal stop codon at position 147. This insertion causes a frameshift which results in elongation of the β chain by 11 amino acids. This variant has previously been described in a few Thai families. We report the DNA sequence of Hb Tak in an individual of Cambodian descent who is a Hb E/Hb Tak compound heterozygote. In contrast with extended variants of the α- globin chain that are expressed as α-thalassemias, the hematologic effect of Hb Tak/Hb E is a mild polycythemia. The combination of Hb Tak/Hb E is not expressed as a thalassemia.
|Original language||English (US)|
|Number of pages||8|
|State||Published - 1998|
ASJC Scopus subject areas