title: AVP-NPII gene mutations and clinical characteristics of the patients with autosomal dominant familial central diabetes insipidus.
abstract: BACKGROUND
  Familial central diabetes insipidus (DI), usually an autosomal dominant disorder, is caused by mutations in arginine vasopressin-neurophysin II (AVP-NPII) gene that leads to aberrant preprohormone processing and gradual destruction of AVP-secreting cells.
  
  
  OBJECTIVE
  To determine clinical and molecular characteristics of patients with familial central DI from two different Turkish families.
  
  
  METHODS
  The diagnosis of central DI was established by 24-h urine collection, water deprivation test, and desmopressin challenge. To confirm the diagnosis of familial central DI, the entire coding region of AVP-NPII gene was amplified and sequenced. A total of eight affected patients and three unaffected healthy relatives from two families were studied.
  
  
  RESULTS
  Genetic analysis revealed a previously reported heterozygous mutation (p.C98X) in family A, and a heterozygous novel mutation (p.G45C) in family B, both detected in exon 2 of AVP-NPII gene. When we compared the clinical characteristics of the two families, it was noticed that as the age of onset of symptoms in family A ranges between 4 and 7 years, it was <1 year in family B. Additionally, pituitary bright spot was present in the affected siblings, but absent in their affected parents.
  
  
  CONCLUSIONS
  Familial central DI is a progressive disease, and age of onset of symptoms can differ depending on the mutation. Bright spot on pituitary MRI might be present at onset, but become invisible over time. Genetic testing and appropriate counseling should be given in familial cases of central DI to ensure adequate treatment, and to avoid chronic water deprivation that might result in growth retardation in childhood.
authors.affiliation: Department of Pediatric Endocrinology, Antalya Education and Research Hospital, Antalya, Turkey. drdoga@hotmail.com.
authors.forename: Doga
authors.initials: D
authors.lastname: Turkkahraman
authors.affiliation: Department of Biology, Faculty of Science, Hacettepe University, Beytepe, Ankara, Turkey.
authors.forename: Emel
authors.initials: E
authors.lastname: Saglar
authors.affiliation: Department of Biology, Faculty of Science, Hacettepe University, Beytepe, Ankara, Turkey.
authors.forename: Tugce
authors.initials: T
authors.lastname: Karaduman
authors.affiliation: Department of Biology, Faculty of Science, Hacettepe University, Beytepe, Ankara, Turkey.
authors.forename: Hatice
authors.initials: H
authors.lastname: Mergen
mesh_terms: D000328:Adult; D002648:Child; D020790:Diabetes Insipidus, Neurogenic / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D009481:Neurophysins / Q000235:genetics*; D011498:Protein Precursors / Q000235:genetics*; D014667:Vasopressins / Q000235:genetics*
chemical_list: C438657:AVP protein, human; D009481:Neurophysins; D011498:Protein Precursors; D014667:Vasopressins
keywords: AVP-NPII gene; Familial central diabetes insipidus; Mutation