Published online Dec 26, 2022. doi: 10.12998/wjcc.v10.i36.13443
Peer-review started: September 29, 2022
First decision: October 31, 2022
Revised: November 11, 2022
Accepted: December 8, 2022
Article in press: December 8, 2022
Published online: December 26, 2022
Processing time: 88 Days and 2.6 Hours
Congenital nephrogenic diabetes insipidus (CNDI) is a rare hereditary disorder. It is associated with mutations in the arginine vasopressin receptor 2 (AVPR2) gene and aquaporin 2 (AQP2) gene, and approximately 270 different mutation sites have been reported for AVPR2. Therefore, new mutations and new manifestations are crucial to complement the clinical deficiencies in the diagnosis of this disease. We report a case of a novel AVPR2 gene mutation locus and a new clinical mani-festation.
We describe the case of a 48-d-old boy who presented with recurrent fever and diarrhea 5 d after birth. Laboratory tests showed electrolyte disturbances and low urine specific gravity, and imaging tests showed no abnormalities. Genetic testing revealed a novel X-linked recessive missense mutation, c.283 (exon 2) C>T (p.P95S). This mutation results in the substitution of a proline residue with a serine residue in the AVPR2 protein sequence. The diagnosis of CNDI was confirmed based on the AVPR2 gene mutation. The treatment strategy for this patient was divided into two stages, including physical cooling supplemented with appropriate amounts of water in the early stage and oral hydrochlorothia-zide (1-2 mg/kg) after a clear diagnosis. After follow-up of one and a half years, the patient gradually improved.
AVPR2 gene mutations in new loci and new clinical symptoms help clinicians understand this disease and shorten the diagnosis cycle.
Core Tip: In this case, a pediatric patient with congenital nephrogenic diabetes insipidus harbored a mutation in the arginine vasopressin receptor 2 (AVPR2) gene at a new locus. In addition, the diarrhea observed in this case is likely related to the novel AVPR2 gene mutation. Therefore, the description of new mutations and new manifestations are crucial to complement the clinical deficiencies in the diagnosis of the disease. We report a case harboring an AVPR2 gene mutation at a new locus and a new clinical manifestation.