nephrogenic syndrome of inappropriate antidiuresis

(NSIAD) a hyponatremic syndrome, clinically resembling the syndrome of inappropriate diuretic hormone, caused by inability of the renal collecting tubules to absorb water in response to antidiuretic hormone. Type I, which accounts for 90 percent of cases, is an X-linked syndrome caused by loss of vasopressin receptor function as a result of mutations in the gene encoding the receptors (locus: Xq28). Type II is caused by a mutation in the gene encoding aquaporin-2 (locus: 12q13); inheritance may be autosomal dominant or recessive.