Dent Disease Type 2

Dent disease type 2 is a type of Dent disease in which patients have the manifestations of Dent disease type 1 associated with extra-renal features.

Epidemiology

About 20 cases have been reported to date.

Clinical description

All of them had hypercalciuria and low-molecular-weight (LMW) proteinuria. In addition, these patients may also have nephrocalcinosis, nephrolithiasis, hematuria, hypophosphatemia and/or renal insufficiency. Only a minority (approximately one fourth) of these patients have been observed to have mild intellectual deficit, hypotonia and sub-clinical cataract. The presence of intellectual impairment and sub-clinical cataract were so mild as to dissuade the clinicians from considering a diagnosis of Lowe syndrome (see this term), which is characterized by congenital cataracts, delayed motor milestones, some degree of intellectual impairment in almost all affected males, growth retardation, rickets and renal proximal tubulopathy. Moreover, the patients with Dent disease type 2 and mild intellectual deficit were adults, who had not, over time, developed more overt features of Lowe syndrome.

Etiology

The reported patients share mutations in the OCRL1 gene with the oculocerebrorenal syndrome of Lowe.

Genetic counseling

The disease follows an X-linked recessive mode of inheritance.