UGT1A1 and cholelithiasis: The frequency of cholelithiasis in the study groups revealed; 40% SCA patients with UGT1A1 (TA)6\6 genotype developed gallstones, 76.5% heterozygotes (TA)6\7 and 100% homozygous SCA patients with UGT1A1 (TA)7\7 had cholelithiasis (Table 3).