IMPA1 (inositol monophosphatase 1) is a phosphatase that catalyzes dephosphorylation of myo-inositol monophosphates to generate free myo-inositol 12, which is essential for synthesis of phosphatidylinositols and maintaining normal brain function 3. The enzyme also dephosphorylates various inositol polyphosphates and sugar-phosphates in vitro 1. IMPA1 serves as a pharmacological target for lithium, which inhibits the enzyme to reduce PIP2 resynthesis and PLC signaling, thereby decreasing neuronal excitability—a mechanism relevant to bipolar disorder treatment 4. Beyond psychiatric applications, IMPA1 has emerged as a critical metabolic regulator in cancer: it maintains stemness in castration-resistant prostate cancer via IMPDH2 activation 5, promotes triple-negative breast cancer progression through mTOR pathway and EMT activation 6, and induces M2-type macrophage polarization in hepatocellular carcinoma 7. Clinically, loss-of-function mutations in IMPA1 cause autosomal recessive intellectual disability characterized by impaired neurogenesis 8, while IMPA2 variants show association with bipolar disorder susceptibility 9. These findings establish IMPA1 as a multifunctional enzyme with roles in normal neurodevelopment, psychiatric disorders, and cancer metabolism.