title: Congenital nephrogenic diabetes insipidus with a novel mutation in the aquaporin 2 gene.
abstract: Congenital nephrogenic diabetes insipidus (CNDI) is a rare disorder caused by mutations of the arginine vasopressin (AVP) V2 receptor or aquaporin 2 (AQP2) genes. The current study presented the case of CNDI in a 1-month-old male with a novel mutation in theAQP2gene. The patient was referred due to the occurrence of hypernatremia and mild-intermittent fever since birth. An AVP stimulation test was compatible with CNDI as there was no significant response to desmopressin. Molecular genetic analysis demonstrated two mutations in exon 1 of theAQP2gene: C to T transition, which resulted in a missense mutation of108Thr (ACG) to Met (ATG); and a 127, 128 delCA, which resulted in a deletion mutation of glutamine in position 43 at codon CAG as the first affected amino acid, with the new reading frame endign in a termination codon at position 62. The molecular genetic analysis of the parents showed that the missense mutation was inherited maternally and the deletion mutation was inherited paternally. The parents showed no signs or symptoms of CNDI, indicating autosomal recessive inheritance. The108Thr (ACG) to Met (ATG) mutation was confirmed as a novel mutation. Therefore, the molecular identification of theAQP2gene has clinical significance, as early recognition of CNDI in infants that show only non-specific symptoms, can be facilitated. Thus, repeated episodes of dehydration, which may cause physical and mental retardation can be avoided.
authors.affiliation: Department of Pediatrics, School of Medicine, Eulji University, Daejeon 302-799, Korea.
authors.forename: Youn Jong
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine, Eulji University, Daejeon 302-799, Korea.
authors.forename: Haing Woon
authors.initials: HW
authors.lastname: Baik
authors.affiliation: Department of Pediatrics, Seoul National University Children's Hospital, Seoul 110-799, Korea.
authors.forename: Hae Il
authors.initials: HI
authors.lastname: Cheong
authors.affiliation: Department of Pediatrics, School of Medicine, Eulji University, Daejeon 302-799, Korea.
authors.forename: Ju Hyung
authors.initials: JH
authors.lastname: Kang
keywords: aquaporin 2 gene; deletion mutation; missense mutation; nephrogenic diabetes insipidus