Dent disease is characterized by renal Fanconi syndrome with low molecular weight proteinuria, hypercalciuria, nephrolithiasis (kidney stones), nephrocalcinosis (calcification of renal tissue) and progressive renal failure. Hypophosphatemic rickets in the first years of life can be a presenting feature. Renal tubular dysfunction may be evident even in the neonatal period. Mutations in the CLCN5 gene have been observed in patients with Dent disease but not in patients with isolated nephrolithiasis. Genetic heterogeneity in Dent Disease exists as mutations in the OCRL1 gene, encoding a phosphatidylinositol 4,5-bisphosphate (PIP2) 5-phosphatase, have been found in approximately 40% of families with the isolated renal phenotype of Dent disease who did not have mutations in CLCN5. These patients also lacked the classic findings of cataract, renal tubular acidosis and neurological abnormalities characteristic of Lowe syndrome.