Hereditary Persistence of Fetal Hemoglobin and Genetic Heterogeneity in Alexandria, Egypt

Abstract

Fetal hemoglobin [HbF] production in normal adults varies over a 20-fold range and is under genetic control. To estimate and assess the mode of inheritance of hereditary persistence of fetal hemoglobin [HPFH], 1009 apparently health preparatory school students were included in this study. Fetal hemoglobin and other hematological indices were determined in these subjects. Four hundred and twenty four subjects had HbF representing 42.4%. The levels of HbF ranged from 0.4%-39.5%. The frequency distribution of HbF showed 2 groups, low [≤9.5% for F1, ≤5% for F2] and high HbF group [>9.5% for F1, >5% for F2]. The hemoglobin [Hb] content showed a positive correlation with HbF level which may indicate the increased HbF in mildly anemic adults. Mathematics of population genetic on families of 66 subjects with elevated HbF showed that autosomal dominant inheritance was the possible mode in 18 families [X2 = 9.68]. In other families, the value of heritability for the first degree relatives was 91% suggesting the multifactorial inheritance. In conclusion, this form of HPFH is heterogenous and the mode of inheritance is different in different families.