Genetic origin of Hb D-Los Angeles [beta121(GH4)Glu-->Gln, GAA-->CAA] according to the beta-globin gene cluster haplotypes.

Hb D-Los Angeles (also known as D-Punjab, D-North Carolina, D-Portugal, D-Chicago and Oak Ridge) is an abnormal hemoglobin (Hb) with an amino acid substitution of glutamine for glutamic acid at codon 121 of the beta-globin gene. The origin and spread of Hb D-Los Angeles is not known. This is due to lack of information and remains to be elucidated. According to published reports, the Hb D-Los Angeles mutation is mostly linked with Mediterranean haplotype I [+ - - - - + +]. Besides the Mediterranean haplotype, a novel haplotype was also reported from Thailand [- - + + - - + + +]. Here we report a new haplotype from Turkey [- + -- + + +] that has not been described before. These results suggest that the Hb D-Los Angeles mutation has at least three different genetic origins.