Anthropological consideration on prevalence and fitness of β C and β S genotypes in Burkina Faso (a survey in the public schools)

Abstract

Objective: To study the incidence of hemoglobinopathies (Hb C and Hb S) we have examined 15,367 students, aged 11.4 +/-4.64 years (median 11; range 1-26), living in Burkina Faso (12,019 were students of 23 public schools of Ouagadougou and 3348 students of 7 public schools situated in six villages about 12-35 Km from Ouagadougou).Results: In all schools, we found a prevalence of females (54.2%) over males (45.8%) with a high incidence of Hb AC (19.16%), over Hb AS (8.35%). As expected, the gene frequency of B C in the schools of Ouagadougou was 0.112 +/-0.015 and of B S 0.049 +/-0.012, and this was similar in village schools (0.128 +/-0.010 and 0.049 +/-0.09 respectively), irrespective of town latitude. In all groups studied, 13 S and 13 C gene frequencies were age dependent since the advantage of HbS carriers in a malarial region is prevalently expressed in the first years of life. In fact, 13 C gene frequency increases, and 13 S decreases with age. The Mossi, living mainly in Ouagadougou, show a gene frequency which is similar to the Bissa ethnic groups, where the 13 C gene frequencies (0.116 and 0.118) are higher than the 13 S (0.049 and 0.044 respectively). On the contrary in the Peuhl ethhic group 13 C and 13 S gene frequencies (0.049 and 0.049) are the same, while in the Yorouba ethnic group immigrated from Nigeria 13 S gene frequency is higher (0,117) than the 13 C (0.068), showing that different genr frequencies are found in different ethnic groups. Conclusion: The difference in 13 S and 13 C genes frequencies (0.049 and 0.116) found in comparison with a previously performed study (Labie et al, 1984) in the same region (0.03 for the B S gene and 0.14 for the 13 C gene)~ may be due to migration flow of 13 S genes from the near Sahel region or to changes in life expectancy of children with 13 C and i~ S phenotypes. Moreover, the high percentage of SC (1,06%) and SS (0.188%) individuals detected with the present screening, compared with the lower percentages found by Labie et al in 1984, suggest that a modified environment can play an important role in reducing the morbility and lethality of 13 S genotype. HoweVer, even today the number of students affected by HbSC and lib SS attending the schools remains low. Stricter controls of correlated diseases are necessary to guarantee healthier life conditions. Anthropological consideration on prevalence fitness of B C and B S genotypes in Burkins Faso (a survey in the public schools) is a reprint of the publication published in the last issue

Hemoglobin AE, AO-Arab and SO-Arab Genotypes in Burkina Faso: Hematological Parameters, Genotypic and Allelic Frequencies of Hemoglobinopathies

“…However, some studies report more HbSS subjects than HbSC individuals 19,20 . These differences could be due to the Burkinabe origin of HbC 15,21 and the demographic data of each country because the sickle cell disease is not a X-linked inherited disease 8 . HbC is the most common abnormal hemoglobin in West Africa with its epicenter located in Burkina Faso (in the Mossi plateau, Bissa country), northern Ghana, northern Benin and northern Togo 21 .…”