OBJECTIVETo detect potential mutation in a pedigree affected with congenital nephrogenic diabetes insipidus (NDI).

METHODSClinical data of a male patient affected with NDI was collected. Genomic DNA was extracted from peripheral blood samples from the patient and five family members. The whole coding region of the arginine vasopressin receptor 2 (AVPR2) gene was amplified by PCR and directly sequenced.

RESULTSThe patient presented polyuria and polydipsia postnatally. Computerized tomography revealed bilateral hydronephrosis and hydroureter. The patient was responsive to hydrochlorothiazide but not to desmopressin. DNA analysis identified a hemizygous missence mutation c.295 T>C in exon 2 of the AVPR2 gene in the proband. His mother and grandmother were both heterozygous for the same mutation.

CONCLUSIONThe congenital NDI in the patient was probably due to mutation of the AVPR2 gene.