UNLABELLED: Familial neurohypophyseal diabetes insipidus (FNDI) is a rare hereditary disorder with unknown prevalence characterized by arginine-vasopressin hormone (AVP) deficiency resulting in polyuria and polydipsia from early childhood. We report the clinical manifestation and genetic test results in seven unrelated kindreds of Czech or Slovak origin with FNDI phenotype. The age of the sign outset ranged from 2 to 17 years with remarkable interfamilial and intrafamilial variability. Inconclusive result of the fluid deprivation test in three children aged 7 and 17 years old might cause misdiagnosis; however, the AVP gene analysis confirmed the FNDI. The seven families segregated together five different mutations, two of them were novel (c.164C > A, c.298G > C). In addition, DNA analysis proved mutation carrier status in one asymptomatic 1-year-old infant. CONCLUSIONS: The present study together with previously published data identified 38 individuals with FNDI in the studied population of 16 million which predicts a disease prevalence of 1:450,000 for the Central European region. The paper underscores that diagnostic water deprivation test may be inconclusive in polyuric children with partial diabetes insipidus and points to the clinical importance and feasibility of molecular genetic testing for AVP gene mutations in the proband and her/his first degree relatives. WHAT IS KNOWN: • At least 70 different mutations were reported to date in about 100 families with neurohypophyseal diabetes insipidus (FNDI), and new mutations appear sporadically. What is New: • Two novel mutations of the AVP gene are reported • The importance of molecular testing in children with polyuria and inconclusive water deprivation test is emphasized.

• Klíčová slova
• AVP gene, FNDI, Mutation, Polyuria, Water deprivation test,
• MeSH
• arginin vasopresin genetika   MeSH
• centrální diabetes insipidus epidemiologie   genetika   MeSH
• dítě MeSH
• dospělí MeSH
• genetické testování metody   MeSH
• heterozygot MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mozek diagnostické zobrazování   patologie   MeSH
• mutace * MeSH
• polydipsie etiologie   MeSH
• polyurie etiologie   MeSH
• prevalence MeSH
• rodina MeSH
• sekvence nukleotidů MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• věk při počátku nemoci MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Slovenská republika epidemiologie   MeSH
• Názvy látek
• arginin vasopresin MeSH