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 β C in the schools of Ouagadougou was 0.112+/-0.015 and of β 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, β S and β 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, β C gene frequency increases, and β S decreases with age. The Mossi, living mainly in Ouagadougou, show a gene frequency which is similar to the Bissa ethnic groups, where the β C gene frequencies (0.116 and 0.118) are higher than the β S (0.049 and 0.044 respectively). On the contrary in the Peuhl ethnic group β C and β S gene frequencies (0.049 and 0.049) are the same, while in the Yorouba ethnic group immigrated from Nigeria β S gene frequency is higher (0.117) than the β C (0.068), showing that different gene frequencies are found in different ethnic groups.
Conclusion: The difference in β S and β 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 β S gene and 0.14 for the β C gene), may be due to migration flow of β S genes from the near Sahel region or to changes in life expectancy of children with β C and β 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 β S genotype. However, even today the number of students affected by HbSC and Hb SS attending the schools remains low. Stricter controls of correlated diseases are necessary to guarantee healthier life conditions.