LHPP and major depressive disorder: As one of the only 3 known pHis phosphatases, LHPP has long been recognized as a risk gene only for major depressive disorder [13,14].In 2018, Hall and Hunter first reported that LHPP, a tumor suppressor in liver cancer, is triggered by phosphatidylinositol 3-kinase (PI3K)–AKT phosphorylation (pSer) [8].