title: Novel AVPR2 mutation causing partial nephrogenic diabetes insipidus in a Japanese family.
abstract: BACKGROUND
  X-linked recessive congenital nephrogenic diabetes insipidus (NDI) is caused by mutations of the arginine vasopressin type 2 receptor gene (AVPR2). More than 200 mutations of the AVPR2 gene with complete NDI have been reported although only 15 mutations with partial NDI has been reported to date.
  
  
  METHODS
  We herein report a Japanese kindred with partial NDI. The proband is an 8-year-old boy who was referred to our hospital for nocturnal enuresis. Water deprivation test and hypertonic saline test suggested partial renal antidiuretic hormone arginine vasopressin (AVP) resistance.
  
  
  RESULTS
  Analysis of genomic DNA revealed a novel missense mutation (p.L161P) in the patient. The patient's mother was heterozygous for the mutation. Three-dimensional (3-D) modeling study showed that L161P possibly destabilizes the transmembrane domain of the V2 receptor, resulting in its misfolding or mislocalization.
  
  
  CONCLUSIONS
  Distinguishing partial NDI from nocturnal enuresis is important. A clinical clue for diagnosis of partial NDI is an incompatibly high level of AVP despite normal serum osmolality.
authors.forename: Sumie
authors.initials: S
authors.lastname: Yamashita
authors.forename: Astuko
authors.initials: A
authors.lastname: Hata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Usui
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Oda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hijikata
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Shirai
authors.forename: Naoto
authors.initials: N
authors.lastname: Kaneko
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hata
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002648:Child; D004252:DNA Mutational Analysis / Q000379:methods; D018500:Diabetes Insipidus, Nephrogenic / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007564:Japan; D008297:Male; D020125:Mutation, Missense / Q000235:genetics*; D010375:Pedigree; D016133:Polymerase Chain Reaction; D011379:Prognosis; D011487:Protein Conformation; D017483:Receptors, Vasopressin / Q000737:chemistry / Q000235:genetics*
chemical_list: C585768:AVPR2 protein, human; D015415:Biomarkers; D017483:Receptors, Vasopressin