In addition to this, genetic variants in STAT6, high affinity receptor for IgE (FCER1A) and HLA-DRB1 genes have been found to influence susceptibility to various infectious and immune-mediated diseases [86, 87], and could be potential determinants of impaired immune response and high IgE concentration in CS. This evidence concerns the gene HLA-DRB1 and Cowden syndrome 1.