HUS is due to various strains of STEC [4], which may generate two major types of Shiga toxin (Stx): Stx1, a family consisting of Stx1, 1c, and 1d, and the more heterogeneous Stx2 family, comprising the variants Stx2c, 2c2, 2d, 2d-activatable, 2e, and 2f [5]. This evidence concerns the gene STX1A and hemolytic-uremic syndrome.