Phosphoinositides constitute a class of seven phospholipids found in cell membranes, regulating various cellular processes like trafficking and signaling. Mutations in their metabolizing enzymes are implicated in several pathologies, including X-Linked Myotubular Myopathy (XLMTM), a severe myopathy caused by mutations in the MTM1 gene. MTM1 acts as a phosphoinositide 3-phosphatase, targeting PI3P and PI(3,5)P