As observed in other population groups, the UGT1A1 (AT)7 homozygosity was significantly associated with raised serum total bilirubin level, but the prevalence of gallstones in the Omani SCA patients was not associated with α thalassaemia, UGT1A1 polymorphism, or βs haplotypes. This evidence concerns the gene UGT1A1 and gallstones.