Interleukin-4 and IL-13 genes are located in a region of 140 kb on chromosome 5q31-33, which codes for a cluster of Th2 cytokines, and gene polymorphisms play an important role in the pathogenesis of atopic diseases, including AD, but also allergic rhinitis, idiopathic nephrotic syndrome, and asthma [94]. This evidence concerns the gene IL13 and Alzheimer disease.