scholarly journals SAT-093 Two Cases of Autosomal Dominant Familial Central Diabetes Insipidus: A Novel Variant in Neurophysin II Region of AVP Gene

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Pablo Ramirez, Biochemist ◽  
Elisa Vaiani ◽  
Roxana Marcela Marino, Biochemist ◽  
Natalia Isabel Perez-Garrido, Biochemist ◽  
Cintia Morales ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Conformational Changes ◽  
Signal Peptide ◽  
Structural Changes ◽  
Autosomal Dominant ◽  
Disulfide Bridge ◽  
Central Diabetes Insipidus ◽  
Novel Variant ◽  
Neurophysin Ii ◽  
Avp Gene

Abstract Central diabetes insipidus (CDI) is a disorder of water balance characterized by polyuria and polydipsia owing to partial or complete deficiency of the antidiuretic hormone, arginine vasopressin (AVP). Although non-hereditary causes are the most frequent, Familial CDI forms, due to heterozygous mutations in the AVP gene, have also long been recognized. Inheritance occurs mostly in an autosomal dominant manner with almost complete penetrance. The AVP gene encodes for a 164 aminoacids preprotein: the AVP preprohormone which consists of a signal peptide, AVP hormone (9 amino acidpeptide), Neurophysin II (AVP carrier), and a glycoprotein, Copeptin. The AVP preprohormone, is produced in the hypothalamus sand is targeted to the endoplasmic reticulum (ER) by the signal peptide. After cleavage and processing, the AVP hormone is packaged within protein carrier NPII and are transported by axonal trafficking to the neurohypophysis where they can be stored and secreted. Structural changes in NPII have been associated with intracellular accumulation of mutant AVP precursors that have been postulated to be cytotoxic and decreased cell viability of vasopressin-producing neuronsin the neurohypophysis. In this study we describe two index cases from two families of four-generation kindred suspected to have Familial neurohypophyseal diabetes insipidus (FNDI), with absent or barely visibleposterior pituitary by MRI. A water deprivation test was performed in both cases, resulting confirmatory for DI in case 1 while it was inconclusive in case 2. In both cases, molecular studies revealed a pathogenic variant in heterozygous state in the NPII region of the AVP gene, in case 1 we found a previously reported and well characterized variant p.Cys116Gly, cysteine at codon 116 is involved in disulfide bridge important for the secondary structure of NPII. While in case 2 we found a novel variant, p.Gly45Val, in which all in silico tools predict deletereous, whereas there are a previously reported patogenic variant at the same amino acid residueand in 3D modeling it can be observed that structural and conformational changes occur in binding bridge of NPII. We are reporting two novel non related familial CDI cases, even though lack of functional studies, the clinical phenotype in each pedigree suggest this diagnosis, and support the genetic counseling.

scholarly journals Autosomal dominant familial neurohypophyseal diabetes insipidus caused by a novel missense mutation in AVP gene in a large Italian kindred

Endocrine ◽  
2021 ◽  
Author(s):  
Carlotta Marzocchi ◽  
Silvia Cantara ◽  
Alfonso Sagnella ◽  
Maria Grazia Castagna ◽  
Marco Capezzone
Keyword(s):  
Diabetes Insipidus ◽  
Missense Mutation ◽  
Autosomal Dominant ◽  
Three Dimensional ◽  
Rare Condition ◽  
Central Diabetes Insipidus ◽  
Disulfide Bridges ◽  
Italian Family ◽  
Avp Gene

Abstract Purpose Familial neurohypophysial diabetes insipidus (FNDI), commonly caused by autosomal dominant arginine vasopressin (AVP) mutations, is a rare condition in which vasopressin fails in regulating body’s level of water with final polyuria and polydipsia. Genetic testing in familial cases of FNDI should be carry out to ensure adequate treatments and avoid disease manifestations especially in infants. Methods In this study, we investigated three-generations of a large Italian family with clinical diagnosis of familial central diabetes insipidus for the presence of potential pathogenic mutations in the AVP gene. Results We identified a heterozygous missense mutation (c.154 T > A; p.C52S) in AVP gene in all affected members studied of a large Italian family. In silico tools were used to investigate the pathogenic role of the mutation and three-dimensional protein structure predicted that the p.C52S impairs disulfide bridges formation resulting in misfolding of the protein. Conclusions This is the first study that identified a novel missense p.C52S mutation as causative of central diabetes insipidus in a large Italian pedigree.

scholarly journals Identification of Mutations of the Arginine Vasopressin-Neurophysin II Gene in Two Kindreds with Familial Central Diabetes Insipidus

1998 ◽  
Vol 83 (2) ◽  
pp. 693-696 ◽  
Author(s):  
Christina Heppner ◽  
Jörg Kotzka ◽  
Catharina Bullmann ◽  
Wilhelm Krone ◽  
Dirk Müller-Wieland
Keyword(s):  
Diabetes Insipidus ◽  
Missense Mutation ◽  
Signal Peptide ◽  
Arginine Vasopressin ◽  
Family Members ◽  
Central Diabetes Insipidus ◽  
Nucleotide Position ◽  
Coding Region ◽  
Control Subjects ◽  
Neurophysin Ii

Familial central diabetes insipidus is transmitted as an autosomal dominant trait with almost complete penetrance. Twenty-three different mutations of the arginine vasopressin-neurophysin II gene have been reported to date, located within the signal peptide-, the arginine vasopressin-, or the neurophysin II-coding region. In the present study two kindreds with familial central diabetes insipidus were examined. The entire coding region of the arginine vasopressin-neurophysin II gene of one affected subject of each family was amplified by PCR and subcloned into a pUC 18 plasmid, and six positive clones were sequenced. After identification of the mutation, direct sequencing was performed on the respective sequence of family members and 28 healthy control subjects. In family A, a missense mutation (C→T) at nucleotide position 280 was detected, predicting the substitution of alanine by valine at position −1 of the signal peptide. All affected subjects were heterozygote for the mutation, whereas none of the unaffected family members or control subjects displayed the mutant sequence. In family B, a missense mutation within the neurophysin II-coding sequence was identified (nucleotide 1757, G→C), predicting the substitution of glycine by arginine at position 23. Again, affected family members were found to be heterozygote for the mutation, which was not observed in unaffected family members or in control subjects. Although the mutation of family A was recently described in 3 other kindreds as well, the mutation within the neurophysin II-coding region represents a novel mutation of the AVP-NP II gene.

Signal Peptide and Neurophysin II Gene Mutations in Hereditary Central Diabetes Insipidus

Physiology ◽  
1997 ◽  
Vol 12 (2) ◽  
pp. 67-71
Author(s):  
J Rutishauser ◽  
ER Froesch
Keyword(s):  
Diabetes Insipidus ◽  
Antidiuretic Hormone ◽  
Signal Peptide ◽  
Gene Mutations ◽  
Central Diabetes Insipidus ◽  
Carrier Protein ◽  
Gene Encoding ◽  
Precursor Processing ◽  
The Impact ◽  
Neurophysin Ii

Recent studies on the molecular background of central diabetes insipidus have identified several mutations in the gene encoding antidiuretic hormone and its carrier protein neurophysin II. This article discusses the impact of such mutations on precursor processing and transport in neuronal cells.

scholarly journals Clinical and molecular analysis of three families with autosomal dominant neurohypophyseal diabetes insipidus associated with a novel and recurrent mutations in the vasopressin-neurophysin II gene

2002 ◽  
pp. 649-656 ◽  
Author(s):  
J Rutishauser ◽  
P Kopp ◽  
MB Gaskill ◽  
TJ Kotlar ◽  
GL Robertson
Keyword(s):  
Diabetes Insipidus ◽  
Autosomal Dominant ◽  
De Novo ◽  
Index Patient ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Heterozygous Mutation ◽  
Posterior Pituitary ◽  
Recurrent Mutations ◽  
Neurophysin Ii

OBJECTIVE: To test further the hypothesis that autosomal dominant neurohypophyseal diabetes insipidus (adFNDI) is caused by heterozygous mutations in the vasopressin-neurophysin II (AVP-NPII) gene that exert a dominant negative effect by producing a precursor that misfolds, accumulates and eventually destroys the neurosecretory neurons. METHODS: Antidiuretic function, magnetic resonance imaging (MRI) of the posterior pituitary and AVP-NPII gene analysis were performed in 10 affected members of three unreported families with adFNDI. RESULTS: As in previously studied patients, adFNDI apparently manifested after birth, was due to a partial or severe deficiency of AVP, and was associated with absence or diminution of the hyperintense MRI signal normally emitted by the posterior pituitary, and with a heterozygous mutation in the AVP-NPII gene. In family A, a transition 275G-->A, which predicts replacement of cysteine 92 by tyrosine (C92Y), was found in the index patient, but not in either parent, indicating that it arose de novo. The six affected members of family B had a transversion 160G-->C, which predicts replacement of glycine 54 by arginine (G54R). It appeared de novo in the oldest affected member, and was transmitted in a dominant manner. In family C, six of 15 living affected members were tested and all had a novel transition, 313T-->C, which predicts replacement of cysteine 105 by arginine (C105R). It, too, was transmitted in a dominant manner. As in other patients with adFNDI, the amino acids replaced by the mutations in these three families are known to be particularly important for correct and efficient folding of the precursor. CONCLUSIONS: These findings are consistent with the malfolding/toxicity hypothesis underlying the pathogenesis of adFNDI. Moreover, they illustrate the value of genetic analysis in all patients who develop idiopathic diabetes insipidus in childhood, even if no other family members are affected.

scholarly journals Autosomal dominant familial neurohypophyseal diabetes insipidus caused by a novel mutation in arginine-vasopressin gene in a Brazilian family

2008 ◽  
Vol 52 (8) ◽  
pp. 1272-1276 ◽  
Author(s):  
Maria Edna de Melo ◽  
Suemi Marui ◽  
Vinícius Nahime de Brito ◽  
Marcio Corrêa Mancini ◽  
Berenice B. Mendonca ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Arginine Vasopressin ◽  
Autosomal Dominant ◽  
Novel Mutation ◽  
Direct Sequencing ◽  
Sequencing Analysis ◽  
The Novel ◽  
Autosomal Dominant Disorder ◽  
Vasopressin Gene ◽  
Avp Gene

Autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) is a rare autosomal dominant disorder characterized by polyuria and polydipsia due to deficiency of arginine vasopressin (AVP). More than 50 mutations causing adFNDI have been already reported in the AVP gene. The aim of the present study is to analyze the AVP gene in four generations of one Brazilian kindred with adFNDI. The proband was a 31-year old female with huge hypotonic polyuria (10 L/day) dated from childhood. Molecular analysis included amplification of all exons and exon-intron regions of the AVP gene by PCR and direct sequencing. Sequencing analysis showed a novel point mutation in heterozygous: G88V (GGC>GTC). All affected patients presented the same mutation also in heterozygous, while it was absent in four normal members. We expand the repertoire of mutations in AVP describing the novel G88V mutation in one Brazilian kindred with adFNDI.

A Novel Synonymous Variant in the AVP Gene Associated with Autosomal Dominant Familial Neurohypophyseal Diabetes Insipidus Causes Partial RNA Missplicing

2018 ◽  
Vol 107 (2) ◽  
pp. 167-180
Author(s):  
Helene Kvistgaard ◽  
Jane H. Christensen ◽  
Jan-Ove Johansson ◽  
Niels Gregersen ◽  
Charlotte Siggaard Rittig ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Laser Scanning ◽  
Dna Analysis ◽  
Autosomal Dominant ◽  
Challenge Test ◽  
Family Members ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Synonymous Variant ◽  
Avp Gene

Objective: Autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) is characterized by severe polyuria and polydipsia and is caused by variations in the gene encoding the AVP prohormone. This study aimed to ascertain a correct diagnosis, to identify the underlying genetic cause of adFNDI in a Swedish family, and to test the hypothesis that the identified synonymous exonic variant in the AVP gene (c.324G>A) causes missplicing and endoplasmic reticulum (ER) retention of the prohormone. Design/Patients: Three affected family members were admitted for fluid deprivation test and dDAVP (1-deamino-8-d-arginine-vasopressin) challenge test. Direct sequencing of the AVP gene was performed in the affected subjects, and genotyping of the identified variant was performed in family members. The variant was examined by expression of AVP minigenes containing the entire coding regions as well as intron 2 of AVP. Methods/Results: Clinical tests revealed significant phenotypical variation with both complete and partial adFNDI phenotype. DNA analysis revealed a synonymous c.324G>A substitution in one allele of the AVP gene in affected family members only. Cellular studies revealed both normally spliced and misspliced pre-mRNA in cells transfected with the AVP c.324G>A minigene. Confocal laser scanning microscopy showed collective localization of the variant prohormone to ER and vesicular structures at the tip of cellular processes. Conclusion: We identified a synonymous variant affecting the second nucleotide of exon 3 in the AVP gene (c.324G>A) in a family in which adFNDI segregates. Notably, we showed that this variant causes partial missplicing of pre-mRNA, resulting in accumulation of the variant prohormone in ER. Our study suggests that even a small amount of aberrant mRNA might be sufficient to disturb cellular function, resulting in adFNDI.

Sign in / Sign up

Export Citation Format

Share Document