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). The gene discussed is PTEN; the disease is immune system disorder.