HBG2 and Schnyder corneal dystrophy: Therefore, the financial burden is heavy and the necessary medical care is often out of reach, and patients suffer from multiple SCD complications albeit the vast majority of the patients show the Senegal haplotype (XmnI-rs7482144) bearing the C>T single nucleotide polymorphism (SNP) at position –158 of the Gγ- globin gene (HBG2:g.-158C>T or NM_000184.2(HBG2):c.-211C>T) which is associated with higher fetal hemoglobin (HbF) levels known to result in a less severe clinical expression of SCD [3, 4].