The closely related Lowe syndrome (oculocerebrorenal), an X-linked disease characterized by congenital cataracts, cognitive impairment, proximal tubular dysfunction and arthropathy, is caused by mutations in the inositol polyphosphate 5-phosphatase gene (OCRL; typically in exons 8–23) associated with impaired Rab GTPase binding and clathrin regulation leading to dysfunctional megalin-mediated endocytosis [11]. The gene discussed is OCRL; the disease is oculocerebrorenal syndrome.