For example, phosphatase and tensin homolog (PTEN) regulates phosphoinositide 3-kinase (PI3K) signaling by dephosphorylating PI(3,4,5)P3 and loss-of-function mutations in PTEN have been shown to cause autoimmunity or immunodeficiency associated with IBD (195–197). This evidence concerns the gene PTEN and immunodeficiency disease.