This report describes the occurrence, study and molecular diagnostics of 40
Hb O Arab beta 121 Glu Lys cases and 4
Hb D punjab beta 121 Glu Gln cases in Bulgaria. Hematological, morphological and clinical data for 12 patients with
Hb O arab are listed. Among them we observed 7 simple heterozygotes for
Hb O Arab/Hb A, two double heterozygotes-compounds for Hb O/
beta+-thalassemia and three compounds for Hb O/beta 0-thalassemia (the latter assumed). Also, general hematological, morphological and clinical data are presented for 4
Hb D Punjab carriers, from which two are simple heterozygotes and two are assumed, as compounds for
Hb D/beta 0-thalassemia. The consideration of heterozygosity, homozygosity for both
abnormal hemoglobins and of the compound state of Hb O or
Hb D/
beta-thalassemia or HbS types let us suggest the relative neutrality of the variants and the limitation in their distribution, depending on genetic structure of populations, where they spread. It may be concluded that human
hemoglobin is characterized by marked monomorphism. At the same time, the high frequency of HbS, HbE and HbC in some populations can be well explained by contemporary selectionism; the distribution of relatively neutral
Hb D Punjab and
Hb O Arab with some limitations can follow Kimura's neutralism concept.