This gene encodes a scaffold protein that is a component of the PIKfyve protein kinase complex. This complex is responsible for the synthesis of phosphatidylinositol 3,5-bisphosphate, an important component of cellular membranes, from phosphatidylinositol 3-phosphate. Mice lacking a functional copy of this gene exhibit severe neurodegeneration. Mutations in the human gene have been identified in patients with a childhood onset progressive neurological disorder characterized by impaired movement, dystonia, and striatal abnormalities.