In three SLCO1B1 variants (rs2291075, rs11045819, rs2306283) the heterozygous genotypes (CT, AC and AG, respectively) showed statistically differences between the two groups, with higher frequencies in the FD patients with GIS (respectively 84% versus 35% P = 0.0065, 58% versus 22% P = 0.0289 and 84% versus 38% P = 0.0083, respectively), while the homozygous genotypes CC in rs2291075 and rs11045819 were associated with absence of GIS (respectively 43% versus 8% P = 0.0371 and 70% versus 34% P = 0.0392, respectively). Here, SLCO1B1 is linked to Fabry disease.