Meanwhile, UGT1A1 mutation types differ considerably among ethnic groups: a homozygous TA insertion in the TATA box (TA7) of the UGT1A1 promoter region (TA7/7) commonly occurs in Japanese and Caucasian GS patients10, whereas UGT1A1*6(G71R), but not UGT1A1(TA7/7), is commonly seen in Taiwanese, Korean and Japanese patients11,12. Here, UGT1A1 is linked to Gerstmann syndrome.