Abstract: Abstract：Objective A case of congenital renal diabetes insipidus caused by mutation of arginine vasopressin receptor 2 (AVPR2) gene was reported to explore the clinical significance of AVPR2 gene mutation in congenital nephrotic diabetes insipidus and improve the understanding of the disease. Methods The clinical data of proband and his parents were retrospectively analyzed, and the related literature was reviewed. All exons of AVPR2 were amplified by PCR, and the amplified products were purified and sequenced in two directions. Results The clinical manifestations of the children were recurrent fever and hypernatremia, and hyperchloremia was difficult to correct. There was no abnormality in pituitary nuclear magnetic resonance in the child at the beginning. Short T1 signal disappeared in the posterior pituitary lobe after reexamination. Central diabetes insipidus was not excluded from clinical practice. However, vasopressin test supported renal diabetes insipidus, which caused troubles in clinical diagnosis. The treatment of vasopressin acetate tablets was ineffective. The results of gene analysis confirmed that mutations were found in the subregion of AVPR2 gene in the proband: c.359T (thymine)>G (guanine) caused amino acid changes: p.Met120Arg, which was located on the X chromosome, and the mother of the patient was the carrier of the mutation of AVPR2 gene. Clinical application of hydrochlorothiazide and amiloride in the treatment of the child with urinary volume significantly reduced, confirmed as congenital renal diabetes insipidus. Conclusion Congenital renal diabetes insipidus in infants and young children is rare and its clinical manifestations are not specific. It can only be manifested by repeated fever and electrolyte disturbance, which causes troubles in clinical diagnosis. AVPR2 gene detection can be used for screening and gene diagnosis of congenital renal diabetes insipidus.

Key words: diabetes insipidus, nephrogenic, congenital nephrogenic diabetes insipidus, AVPR2 genes, genetic mutation, child