Sickle cell disease is a group of genetic conditions in which pathology results from the inheritance of the sickle cell gene variant either homozygously or as a double heterozygote with another interacting gene. The spectrum of resulting conditions is influenced by the geography of individual hemoglobin genes, but in most populations, the commonest genotype at birth is homozygous sickle cell (SS) disease. Since this genotype involves a greater mortality, the relative proportion of sickle cell genotypes is influenced by age as well as by the geographical distribution of individual genes.1