Hemoglobins S and C in Upper Volta.

We have studied the incidence of hemoglobinopathies in 1059 individuals in Upper Volta. We have found that this population has a high frequency of HbS and HbC and alpha-thalassemia. The gene frequency of HbS was high (0.1 for the beta s gene) in the arid Sahel portion of Upper Volta accompanied by a lower frequency for HbC (0.05 for the beta c gene). The reverse was true in the humid Savanna region of this country (0.03 for the beta s gene and 0.14 for the beta c gene). There was no age dependency of the HbS gene frequency, but alpha-thalassemia, detectable in HbS heterozygotes, showed a statistically significant decrease with age. No homozygote for HbS was detected after the age of 1 year, and SC and CC genotypes were found at a lower incidence than expected. The environmental and medical conditions in Upper Volta preclude the survival of SS individuals and decrease the survival of SC and CC genotypes.