Lowe syndrome is a rare X-linked disorder caused by the deficiency of a phosphatidylinositol bisphosphate (PIP2) 5-phosphatase. The disorder is characterized by bilateral congenital cataracts, a form of renal Fanconi syndrome, with proteinuria, albuminuria, aminoaciduria and phosphaturia, and neurologic deficits including developmental delay/mental retardation, seizures and behavioral stereotypies. Additional findings include hypotonia, a characteristic facies, postnatal growth retardation and corneal keloids.
Mutations in the OCRL gene also cause a form of Dent disease, known as Dent disease 2 (OMIM 300555). Although the most common cause of Dent disease is mutations in the CLCN5 gene, approximately 16-23% of Dent disease cases are due to mutations in the OCRL gene. Dent disease is a rare X-linked disorder characterized by renal Fanconi syndrome, without the cataracts and neurologic deficits that occur in Lowe syndrome.