(NDI) a condition characterized by polyuria and polydipsia and due to failure of the renal tubules to respond, or to respond fully, to vasopressin. One form of congenital NDI is caused by an X-linked (see sex-linked) dominant mutation of the gene encoding the vasopressin V2 receptor. A rarer form of congenital NDI is an autosomal recessive condition associated with genetic mutations in the gene encoding AQP-2 water channels (see aquaporin). Acquired NDI is much commoner than the congenital form and usually less severe. It is present in most patients with advancing chronic renal failure, is a feature of certain electrolyte disorders (hypokalaemia, hypercalcaemia), and can complicate chronic lithium treatment.
Subjects: Medicine and Health — Chemistry.