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Kermond R, Mallett A, McCarthy H. A clinical approach to tubulopathies in children and young adults. Pediatr Nephrol 2023; 38:651-662. [PMID: 35585366 PMCID: PMC9842573 DOI: 10.1007/s00467-022-05606-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 01/21/2023]
Abstract
Kidney tubules are responsible for the preservation of fluid, electrolyte and acid-base homeostasis via passive and active mechanisms. These physiological processes can be disrupted by inherited or acquired aetiologies. The net result is a tubulopathy. It is important to make a prompt and accurate diagnosis of tubulopathies in children and young adults. This allows timely and appropriate management, including disease-specific therapies, and avoids complications such as growth failure. Tubulopathies can present with a variety of non-specific clinical features which can be diagnostically challenging. In this review, we build from this common anatomical and physiological understanding to present a tangible appreciation of tubulopathies as they are likely to be clinically encountered among affected children and young adults.
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Affiliation(s)
- Rachael Kermond
- Department of Renal Medicine, Sydney Children’s Hospital Network, Sydney, NSW Australia
| | - Andrew Mallett
- Department of Renal Medicine, Townsville University Hospital, Douglas, QLD, Australia. .,College of Medicine and Dentistry, James Cook University, Douglas, QLD, Australia. .,Institute for Molecular Bioscience & Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.
| | - Hugh McCarthy
- Department of Renal Medicine, Sydney Children's Hospital Network, Sydney, NSW, Australia. .,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia. .,Centre for Kidney Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
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Özcan Türkmen M, Karaduman T, Mergen H. Comparison of ELISA and RIA methods to quantify arginine vasopressin hormone levels in cell culture. Biologia (Bratisl) 2022. [DOI: 10.1007/s11756-022-01301-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Genomic analysis of arginine vasopressin gene in riverine buffalo reveals its potential association with silent estrus behavior. Mol Biol Rep 2022; 49:9315-9324. [PMID: 35902449 DOI: 10.1007/s11033-022-07776-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 07/06/2022] [Indexed: 10/16/2022]
Abstract
BACKGROUND Poor estrus expression behavior causes suboptimal reproductive efficiency through poor conception rate. Various signaling pathways are involved in estrus expression but arginine vasopressin (AVP) gene with oxytocin predominantly regulates estrus behavior. This study aimed to perform genomic characterization and evolutionary dynamics of AVP gene through association testing of the novel polymorphic loci and comparative genomic analysis to explore the potential effect of AVP gene on estrus behavior of Nili-Ravi buffaloes. METHODS AND RESULTS 198 Nili-Ravi buffaloes were screened for the quest of novel polymorphism in the AVP gene. In exon-1, five polymorphic sites were detected including deletion of two (c.47delA and c.57delA) nucleotides that caused drastic variation in subsequent amino acid sequence due to frame shift including functional short peptide of nine residues. The 3-D structure revealed a loss of transmembrane loop between 16 and 31 residues in Nili-Ravi buffalo AVP protein sequence, suggesting that missing loop apparently reduced the gene functionality in Nili-Ravi buffalo by inhibiting cellular reactions and muting the animal estrus cyclicity. Three polymorphisms detected in AVP gene were significantly associated with silent estrus (P < 0.05). The comparative genomic analysis revealed that AVP gene is present on chromosome 14 having one conserved motif (Neurohypophysial) in buffalo. CONCLUSIONS This study suggested the potential use of polymorphic sites as promising genetic markers for selection of buffaloes with pronounced estrus expression.
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Türkmen MÖ, Karaduman T, Tuncdemir BE, Ünal MA, Mergen H. Functional analyses of three different mutations in the AVP-NPII gene causing familial neurohypophyseal diabetes insipidus. Endocrine 2021; 74:658-665. [PMID: 34232487 DOI: 10.1007/s12020-021-02803-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 06/14/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE Familial neurohypophyseal diabetes insipidus (FNDI), a rare disorder, which is clinically characterized by polyuria and polydipsia, results from mutations in the arginine vasopressin-neurophysin II (AVP-NPII) gene. The aim of this study was to perform functional analyses of three different mutations (p.G45C, 207_209delGGC, and p.G88V) defined in the AVP-NPII gene of patients diagnosed with FNDI, which are not included in the literature. METHODS For functional analysis studies, the relevant mutations were created using PCR-based site-directed mutagenesis and restriction fragment replacement strategy and expressed in Neuro2A cells. AVP secretion into the cell culture medium was determined by radioimmunoassay (RIA) analysis. Fluorescence imaging studies were conducted to determine the differences in the intracellular trafficking of wild-type (WT) and mutant AVP-NPII precursors. Molecular dynamics (MD) simulations were performed to determine the changing of the conformational properties of domains for both WT and 207-209delGGC mutant structures and dynamics behavior of residues. RESULTS Reduced levels of AVP in the supernatant culture medium of p.G45C and p.G88V transfected cells compared to 207_209delGGC and WT cells were found. Fluorescence imaging studies showed that a substantial portion of the mutant p.G45C and p.G88V AVP-NPII precursors appeared to be located in the endoplasmic reticulum (ER), whereas 207_209delGGC and WT AVP-NPII precursors were distributed throughout the cytoplasm. CONCLUSIONS The mutations p.G45C and p.G88V cause a failure in the intracellular trafficking of mutant AVP-NPII precursors. However, 207_209delGGC mutation does not result in impaired cellular trafficking, probably due to not having any significant effect in processes such as the proper folding, gain of three-dimensional structure, or processing. These results will provide valuable information for understanding the influence of mutations on the function of the AVP precursor hormone and cellular trafficking. Therefore, this study will contribute to elucidate the mechanisms of the molecular pathology of AVP-NPII mutations.
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Affiliation(s)
- Merve Özcan Türkmen
- Department of Biology, Faculty of Science, Hacettepe University, Ankara, Turkey.
- Department of Molecular Biology and Genetics, Faculty of Science, Necmettin Erbakan University, Konya, Turkey.
| | - Tugce Karaduman
- Department of Biology, Faculty of Science, Hacettepe University, Ankara, Turkey
- Department of Biotechnology and Molecular Biology, Faculty of Science and Letters, Aksaray University, Aksaray, Turkey
| | | | | | - Hatice Mergen
- Department of Biology, Faculty of Science, Hacettepe University, Ankara, Turkey
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Feldkamp LLI, Kaminsky E, Kienitz T, Quinkler M. Central Diabetes Insipidus Caused by Arginine Vasopressin Gene Mutation: Report of a Novel Mutation and Review of Literature. Horm Metab Res 2020; 52:796-802. [PMID: 32629514 DOI: 10.1055/a-1175-1307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Familial neurohypophyseal diabetes insipidus (FNDI) is an autosomal dominant hereditary disorder characterized by severe polydipsia and polyuria that usually presents in early childhood. In this study, we describe a new arginine vasopressin (AVP) gene mutation in an ethnic German family with FNDI and provide an overview of disease-associated AVP-gene mutations that are already described in literature. Three members of a German family with neurohypophyseal diabetes insipidus were studied. Isolated DNA from peripheral blood samples was used for mutation analysis by sequencing the whole coding region of AVP-NPII gene. Furthermore, we searched the electronic databases MEDLINE (Pubmed) as well as HGMD, LOVD-ClinVar, db-SNP and genomAD in order to compare our cases to that of other patients with FNDI. Genetic analysis of the patients revealed a novel heterozygote missense mutation in exon 2 of the AVP gene (c.274T>G), which has not yet been described in literature. We identified reports of more than 90 disease-associated mutations in the AVP gene in literature. The novel mutation of the AVP gene seems to cause FNDI in the presented German family. Similar to our newly detected mutation, most mutations causing FNDI are found in exon 2 of the AVP gene coding for neurophysin II. Clinically, it is important to think of FNDI in young children presenting with polydipsia and polyuria.
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Affiliation(s)
- Lara L I Feldkamp
- Endocrinology in Charlottenburg, Berlin, Germany
- Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | - Tina Kienitz
- Endocrinology in Charlottenburg, Berlin, Germany
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Abstract
Diabetes insipidus is a disease characterized by polyuria and polydipsia due to inadequate release of arginine vasopressin from the posterior pituitary gland (neurohypophyseal diabetes insipidus) or due to arginine vasopressin insensitivity by the renal distal tubule, leading to a deficiency in tubular water reabsorption (nephrogenic diabetes insipidus). This article reviews the genetics of diabetes insipidus in the context of its diagnosis, clinical presentation, and therapy.
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Affiliation(s)
- Marie Helene Schernthaner-Reiter
- Clinical Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Vienna 1090, Austria; Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 31 Center Drive, Bethesda, MD 20892, USA.
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 31 Center Drive, Bethesda, MD 20892, USA
| | - Anton Luger
- Clinical Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Vienna 1090, Austria
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Beuret N, Hasler F, Prescianotto-Baschong C, Birk J, Rutishauser J, Spiess M. Amyloid-like aggregation of provasopressin in diabetes insipidus and secretory granule sorting. BMC Biol 2017; 15:5. [PMID: 28122547 PMCID: PMC5267430 DOI: 10.1186/s12915-017-0347-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/04/2017] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Aggregation of peptide hormone precursors in the trans-Golgi network is an essential process in the biogenesis of secretory granules in endocrine cells. It has recently been proposed that this aggregation corresponds to the formation of functional amyloids. Our previous finding that dominant mutations in provasopressin, which cause cell degeneration and diabetes insipidus, prevent native folding and produce fibrillar aggregates in the endoplasmic reticulum (ER) might thus reflect mislocalized amyloid formation by sequences that evolved to mediate granule sorting. RESULTS Here we identified two sequences responsible for fibrillar aggregation of mutant precursors in the ER: the N-terminal vasopressin nonapeptide and the C-terminal glycopeptide. To test their role in granule sorting, the glycopeptide was deleted and/or vasopressin mutated to inactivate ER aggregation while still permitting precursor folding and ER exit. These mutations strongly reduced sorting into granules and regulated secretion in endocrine AtT20 cells. CONCLUSION The same sequences - vasopressin and the glycopeptide - mediate physiological aggregation of the wild-type hormone precursor into secretory granules and the pathological fibrillar aggregation of disease mutants in the ER. These findings support the amyloid hypothesis for secretory granule biogenesis.
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Affiliation(s)
- Nicole Beuret
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
| | - Franziska Hasler
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
| | | | - Julia Birk
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
| | - Jonas Rutishauser
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
| | - Martin Spiess
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland.
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Abstract
Neurohypophyseal diabetes insipidus is characterized by polyuria and polydipsia owing to partial or complete deficiency of the antidiuretic hormone, arginine vasopressin (AVP). Although in most patients non-hereditary causes underlie the disorder, genetic forms have long been recognized and studied both in vivo and in vitro. In most affected families, the disease is transmitted in an autosomal dominant manner, whereas autosomal recessive forms are much less frequent. Both phenotypes can be caused by mutations in the vasopressin-neurophysin II (AVP) gene. In transfected cells expressing dominant mutations, the mutated hormone precursor is retained in the endoplasmic reticulum, where it forms fibrillar aggregates. Autopsy studies in humans and a murine knock-in model suggest that the dominant phenotype results from toxicity to vasopressinergic neurons, but the mechanisms leading to cell death remain unclear. Recessive transmission results from AVP with reduced biologic activity or the deletion of the locus. Genetic neurohypophyseal diabetes insipidus occurring in the context of diabetes mellitus, optic atrophy, and deafness is termed DIDMOAD or Wolfram syndrome, a genetically and phenotypically heterogeneous autosomal recessive disorder caused by mutations in the wolframin (WFS 1) gene.
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Affiliation(s)
- Jonas Rutishauser
- Kantonsspital Baselland, Department of Medicine, CH-4101 Bruderholz, Switzerland; University of Basel, Biozentrum, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland.
| | - Martin Spiess
- University of Basel, Biozentrum, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland.
| | - Peter Kopp
- Northwestern University, Division of Endocrinology, Metabolism and Molecular Medicine, Feinberg School of Medicine, Tarry 15, 303 East Chicago Ave., Chicago, IL 60611, USA.
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Chitturi S, Harris M, Thomsett MJ, Bowling F, McGown I, Cowley D, Leong GM, Batch J, Cotterill AM. Utility of AVP gene testing in familial neurohypophyseal diabetes insipidus. Clin Endocrinol (Oxf) 2008; 69:926-30. [PMID: 18494865 DOI: 10.1111/j.1365-2265.2008.03303.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
CONTEXT Familial neurohypophyseal diabetes insipidus (FNDI) is a rare disorder resulting from arginine vasopressin (AVP) gene mutations. A partial defect in AVP secretion occurs early in the course of FNDI and may not be detected by a water deprivation test (WDT). Testing for AVP gene mutations may confirm a diagnosis of FNDI when a WDT is inconclusive and may also predict individuals who will later develop FNDI. OBJECTIVE To test the utility of AVP gene analysis in confirming the diagnosis of FNDI. PATIENTS Five families (20 subjects, 14 symptomatic and six asymptomatic) with FNDI and nine children with idiopathic neurohypophyseal diabetes insipidus (INDI). MEASUREMENTS Genomic DNA was analysed for AVP gene mutations using polymerase chain reaction (PCR) amplification and sequencing. RESULTS Heterozygous AVP gene mutations were found in all subjects with FNDI but none of the ICDI patients. Each family had their own distinct mutation. We identified two novel mutations (C44W and C105S). One asymptomatic subject developed diabetes insipidus (DI) 4 months after detection of an AVP gene mutation. The WDT suggested partial DI in 4/6 but was normal in 2/6 children with FNDI. CONCLUSION AVP gene testing allowed diagnostic confirmation of FNDI when the WDT was inconclusive in symptomatic children, therefore obviating the need for a repeat WDT and enabling earlier initiation of appropriate treatment. AVP gene testing also has the potential to identify which asymptomatic children will later develop FNDI.
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Affiliation(s)
- Sridhar Chitturi
- Paediatric Endocrinology and Diabetes, Mater Children's Hospital, Brisbane, Australia
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Castino R, Thepparit C, Bellio N, Murphy D, Isidoro C. Akt induces apoptosis in neuroblastoma cells expressing a C98X vasopressin mutant following autophagy suppression. J Neuroendocrinol 2008; 20:1165-75. [PMID: 18673414 DOI: 10.1111/j.1365-2826.2008.01769.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mutations in the arginine vasopressin (AVP)-neurophysin II (NP-II) gene that affect the folding and transport of the prohormone result in loss of secretion of the anti-diuretic hormone AVP from pituitary nerve terminals and cause autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI). One such mutation consists of the replacement of a Cys residue at position 98 with a stop codon (C98X) in the AVP precursor (corresponding to C67X in NP domain). In neuroblastoma cells over-expressing this truncated AVP precursor autophagy, a macromolecular degradation process, was shown to be essential for assuring cell survival. In the present study, we investigated the role of the Akt pro-survival signalling in the regulation of autophagy and of apoptosis linked with the handling of C98X AVP. Impairing autophagy-lysosomal sequestration or cathepsin D (CD)-mediated proteolysis triggered the activation of the intrinsic death pathway of apoptosis in C98X-expressing cells, but not in the wild-type -AVP-expressing cells. This was shown by the expression of a Vps34 dominant negative, which down-regulates the PI3k class III-dependent signalling needed for autophagosome (APH) formation, by genetic silencing as a result of RNA interference (RNAi) of Lamp2, a protein indispensable for the fusion of APHs with lysosomes, and by RNAi silencing of the lysosomal protease CD. Ectopic expression of either the wild-type or the mutated C98X AVP altered neither the expression nor the phosphorylation of the pro-survival signalling molecule Akt. Strikingly, the ectopic adenoviral-directed expression of a constitutively active Akt, instead of preserving cell survival, resulted in the suppression of autophagy, and precipitated Bax-mediated cell death. The present data demonstrate the need for autophagy-mediated degradation of mutated C98X peptides, which otherwise become toxic to the cell, and suggest that, in the presence of mis-folded proteins, the stimulation of the Akt signalling counteracts the beneficial effects of autophagy and precipitates cell death. It follows that growth factors impinging on the Akt pathway may have deleterious effect in neurones expressing mutant neuropeptides. This can provide an explanation for the late onset and progressive neuronal cell loss observed in hypothalamic magnocellular neurones of adFNDI patients.
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Affiliation(s)
- R Castino
- Laboratorio di Patologia Molecolare, Dipartimento di Scienze Mediche, Università del Piemonte Orientale A. Avogadro, Novara, Italy
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Abstract
Although molecular research has contributed significantly to our knowledge of familial neurohypophyseal diabetes insipidus (FNDI) for more than a decade, the genetic background and the pathogenesis still is not understood fully. Here we provide a review of the genetic basis of FNDI, present recent progress in the understanding of the molecular mechanisms underlying its development, and survey diagnostic and treatment aspects. FNDI is, in 87 of 89 kindreds known, caused by mutations in the arginine vasopressin (AVP) gene, the pattern of which seems to be largely revealed as only few novel mutations have been identified in recent years. The mutation pattern, together with evidence from clinical, cellular, and animal studies, points toward a pathogenic cascade of events, initiated by protein misfolding, involving intracellular protein accumulation, and ending with degeneration of the AVP producing magnocellular neurons. Molecular research has also provided an important tool in the occasionally difficult differential diagnosis of DI and the opportunity to perform presymptomatic diagnosis. Although FNDI is treated readily with exogenous administration of deamino-D-arginine vasopressin (dDAVP), other treatment options such as gene therapy and enhancement of the endoplasmic reticulum protein quality control could become future treatment modalities.
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Affiliation(s)
- Jane H Christensen
- Research Unit for Molecular Medicine, Aarhus University Hospital, Skejby Sygehus, Aarhus, Denmark
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Kobayashi H, Fujisawa I, Ikeda K, Son C, Iwakura T, Yoshimoto A, Kasahara M, Ishihara T, Ogawa Y. A novel heterozygous missense mutation in the vasopressin moiety is identified in a Japanese person with neurohypophyseal diabetes insipidus. J Endocrinol Invest 2006; 29:252-6. [PMID: 16682840 DOI: 10.1007/bf03345549] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) is caused by diverse mutations in one allele of the gene that encodes the arginine vasopressin (AVP) precursor protein, AVP-neurophysin II (AVP-NP II). Most of the mutations identified so far are located in either the signal peptide or NP II moiety. Two recently published mutations in the AVP gene identified in kindreds with adFNDI predict a substitution of histidine for tyrosine at position 2 and a deletion of phenylalanine at position 3 in AVP. They are unique among adFNDI mutations in that they are the only adFNDI mutations that affect amino acid residues in the AVP moiety of the pro-hormone. Here, we report a novel heterozygous missense mutation in the AVP moiety of the AVP-NP II gene in a Japanese person with neurohypophyseal diabetes insipidus (DI). This mutation occurs at position 2 in AVP and predicts a substitution of serine for tyrosine (Y21S). It is expected to interfere with normal binding of AVP with NP II, and thus result in misfolding of the precursor proteins. The data of this study support the notion that mutations affecting the AVP moiety can result in the initiation of the pathological processes.
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Affiliation(s)
- H Kobayashi
- Department of Endocrinology, Kobe City General Hospital, 4-6, Minatojimanakamachi, Hyogo, 650-0046 Japan.
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Siggaard C, Christensen JH, Corydon TJ, Rittig S, Robertson GL, Gregersen N, Bolund L, Pedersen EB. Expression of three different mutations in the arginine vasopressin gene suggests genotype-phenotype correlation in familial neurohypophyseal diabetes insipidus kindreds. Clin Endocrinol (Oxf) 2005; 63:207-16. [PMID: 16060916 DOI: 10.1111/j.1365-2265.2005.02327.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE AND STUDY DESIGN The autosomal dominant form of familial neurohypophyseal diabetes insipidus (adFNDI) is a rare disease characterized by a severe and progressive deficiency of AVP secondary to mutations in the gene encoding the AVP precursor. Whereas a number of studies have investigated the pathogenetic mechanisms behind the disease only few studies have included detailed clinical characterization of the affected patients, thereby making genotype-phenotype correlations difficult. The aims of the present study were to investigate the cellular effects of three different adFNDI mutations (A19T, L81P and C110X) by heterologous expression in a neurogenic cell line and to correlate these findings to the corresponding clinical phenotype as determined by extensive clinical tests. RESULTS The clinical studies showed a later age of onset in the family carrying the A19T mutation (3.4 years, range 2-9 years) compared with families with the L81P and C110X mutations [0.75 year, range 0.5-1 year and 1.0 year (n = 1), respectively]. No other differences could be demonstrated in the clinical phenotype between families. Expression studies showed that each of the three mutant genes caused significant reduction of the amount of immunoreactive AVP in the cell culture medium and severe impairment of the intracellular trafficking and processing of the AVP prohormone, supporting the disease causing nature of all three mutations. However, the A19T mutation was associated with some capacity for processing and trafficking consistent with the clinical observations. Immunoflourescence studies provided evidence of reticular accumulation of protein within the ER in the A19T and C110X mutants but a unique accumulation of much larger aggregates in the L81P, which were localized both within and immediately outside the ER. CONCLUSION The study suggests a genotype-phenotype correlation with regard to age of onset of diabetes insipidus symptoms and provides support by expression studies.
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Affiliation(s)
- Charlotte Siggaard
- Department of Pediatrics, Aarhus University Hospital, Skejby Sygehus, Aarhus, Denmark
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Ghirardello S, Malattia C, Scagnelli P, Maghnie M. Current perspective on the pathogenesis of central diabetes insipidus. J Pediatr Endocrinol Metab 2005; 18:631-45. [PMID: 16128239 DOI: 10.1515/jpem.2005.18.7.631] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Diabetes insipidus is a heterogeneous condition characterised by polyuria and polydipsia caused by a lack of secretion of vasopressin, its physiological suppression following excessive water intake, or kidney resistance to its action. The clinical and laboratory diagnosis is confirmed by standard tests, but recent advances in molecular biology and imaging techniques have shed new light on the pathophysiology of this disease. In many patients, central diabetes insipidus is caused by a germinoma or craniopharyngioma; Langerhans' cell histiocytosis and sarcoidosis of the central nervous system; local inflammatory, autoimmune or vascular diseases; trauma from surgery or accident; and, rarely, genetic defects in vasopressin biosynthesis inherited as autosomal dominant or X-linked recessive traits. Thirty to fifty percent of cases are considered idiopathic. Tumour-associated central diabetes insipidus is uncommon in children younger than 5 years old. Biopsy of enlarged pituitary stalk should be reserved for patients with hypothalamic-pituitary mass and progressive thickening of the pituitary stalk since spontaneous recovery may occur. Molecular biology in selected patients may identify those with apparently idiopathic diabetes insipidus carrying the vasopressin-neurophysin II gene mutation.
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Affiliation(s)
- Stefano Ghirardello
- Department of Pediatrics, IRCCS Policlinico S Matteo, University of Pavia, Pavia, Italy
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