Despite the observation that the UGT1A1 (TA) n low -activity genotype is a leading factor in hyperbilirubinemia and lithogenesis among SCA patients [2, 6, 7, 41, 42], the impact of UGT1A1 polymorphism on the phenotypic expression of the Nigerian SCA patients was unknown prior to this study as none of the previous studies from Nigeria examined the UGT1A1 of the patients [31–33]. This evidence concerns the gene UGT1A1 and Hyperbilirubinemia.