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Alvelos MI, Francisco Â, Gomes L, Paiva I, Melo M, Marques P, Gama-de-Sousa S, Carreiro S, Quintela T, Gonçalves I, Lemos MC. Familial neurohypophyseal diabetes insipidus: clinical, genetic and functional studies of novel mutations in the arginine vasopressin gene. Pituitary 2021; 24:400-411. [PMID: 33433888 DOI: 10.1007/s11102-020-01119-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/21/2020] [Indexed: 11/27/2022]
Abstract
PURPOSE Familial neurohypophyseal diabetes insipidus (FNDI) is a rare disorder characterized by childhood-onset progressive polyuria and polydipsia due to mutations in the arginine vasopressin (AVP) gene. The aim of the study was to describe the clinical and molecular characteristics of families with neurohypophyseal diabetes insipidus. METHODS Five Portuguese families with autosomal dominant FNDI underwent sequencing of the AVP gene and the identified mutations were functionally characterized by in vitro studies. RESULTS Three novel and two recurrent heterozygous mutations were identified in the AVP gene. These consisted of one initiation codon mutation in the signal peptide coding region (c.2T > C, p.Met1?), three missense mutations in the neurophysin II (NPII) coding region (c.154T > C, p.Cys52Arg; c.289C > G, p.Arg97Gly; and c.293G > C, p.Cys98Ser), and one nonsense mutation in the NPII coding region (c.343G > T, p.Glu115Ter). In vitro transfection of neuronal cells with expression vectors containing each mutation showed that the mutations resulted in intracellular retention of the vasopressin prohormone. Patients showed progressive symptoms of polyuria and polydipsia, but with wide variability in severity and age at onset. No clear genotype-phenotype correlation was observed. CONCLUSION The intracellular accumulation of mutant vasopressin precursors supports the role of cellular toxicity of the mutant proteins in the etiology of the disorder and explains the progressive onset of the disorder. These findings further expand the AVP mutational spectrum in FNDI and contribute to the understanding of the molecular pathogenic mechanisms involved in FNDI.
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Affiliation(s)
- Maria Inês Alvelos
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilha, Portugal
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Ângela Francisco
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilha, Portugal
| | - Leonor Gomes
- Serviço de Endocrinologia, Diabetes e Metabolismo, Centro Hospitalar Universitário de Coimbra, 3000-075, Coimbra, Portugal
| | - Isabel Paiva
- Serviço de Endocrinologia, Diabetes e Metabolismo, Centro Hospitalar Universitário de Coimbra, 3000-075, Coimbra, Portugal
| | - Miguel Melo
- Serviço de Endocrinologia, Diabetes e Metabolismo, Centro Hospitalar Universitário de Coimbra, 3000-075, Coimbra, Portugal
| | - Pedro Marques
- Serviço de Endocrinologia, Instituto Português de Oncologia de Lisboa, 1099-023, Lisboa, Portugal
| | - Susana Gama-de-Sousa
- Serviço de Pediatria, Centro Hospitalar do Médio Ave, Unidade de V. N. Famalicão, 4761-917, Vila Nova de Famalicão, Portugal
| | - Sofia Carreiro
- Serviço de Patologia Clínica, Instituto Português de Oncologia de Coimbra, 3000-075, Coimbra, Portugal
| | - Telma Quintela
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilha, Portugal
| | - Isabel Gonçalves
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilha, Portugal
| | - Manuel Carlos Lemos
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilha, Portugal.
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Two novel mutations in seven Czech and Slovak kindreds with familial neurohypophyseal diabetes insipidus-benefit of genetic testing. Eur J Pediatr 2016; 175:1199-1207. [PMID: 27539621 DOI: 10.1007/s00431-016-2759-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 07/28/2016] [Accepted: 08/04/2016] [Indexed: 10/21/2022]
Abstract
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.
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