Background/Aim: Variability in the severity and age at onset of autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) may be associated with certain types of variants in the arginine vasopressin (AVP) gene. In this study, we aimed to describe a large family with an apparent predominant female occurrence of polyuria and polydipsia and to determine the underlying cause. Methods: The family members reported their family demography and symptoms. Two subjects were diagnosed by fluid deprivation and dDAVP challenge tests. Eight subjects were tested genetically. The identified variant along with 3 previously identified variants in the AVP gene were investigated by heterologous expression in a human neuronal cell line (SH-SY5Y). Results: Both subjects investigated clinically had a partial neurohypophyseal diabetes insipidus phenotype. A g.276_278delTCC variant in the AVP gene causing a Ser18del deletion in the signal peptide (SP) of the AVP preprohormone was perfectly co-segregating with the disease. When expressed in SH-SY5Y cells, the Ser18del variant along with 3 other SP variants (g.227G>A, Ser17Phe, and Ala19Thr) resulted in reduced AVP mRNA, impaired AVP secretion, and partial AVP prohormone degradation and retention in the endoplasmic reticulum. Impaired SP cleavage was demonstrated directly in cells expressing the Ser18del, g.227G>A, and Ala19Thr variants, using state-of-the-art mass spectrometry. Conclusion: Variants affecting the SP of the AVP preprohormone cause adFNDI with variable phenotypes by a mechanism that may involve impaired SP cleavage combined with effects at the mRNA, protein, and cellular level.

Familial neurohypophyseal diabetes insipidus (FNDI) typically presents with age-dependent penetrance and autosomal dominant inheritance caused by missense variations in one allele of the AVP gene encoding the arginine vasopressin (AVP) prohormone. We present the molecular genetic characteristics underlying an unusual form of FNDI occurring with very early onset and seemingly autosomal recessive inheritance. By DNA amplification and sequencing, we identified a novel variant allele of the AVP gene carrying a 10,396 base pair deletion involving the majority of the AVP gene as well as its regulatory sequences in the intergenic region between the AVP and the OXT gene, encoding the oxytocin prohormone. We found two chromosomes carrying the deletion in affected family members and one in unaffected family members suspected to transmit the deleted allele. Whole-genome array analysis confirmed the results and excluded the presence of any additional major pathogenic abnormalities. The deletion is predicted to abolish the transcription of the AVP gene, thus the fact that family members heterozygous for the deletion remain healthy argues, in general, against haploinsufficiency as the pathogenic mechanism FNDI. Accordingly, our data is strong support to the prevailing idea that dominant inheritance of FNDI is due to a dominant-negative effect exerted by variant AVP prohormone.

A novel mutation in the AVP gene predicted to cause a neurophysin II dimerization defect is causing surprisingly late onset of FNDI in a large, six generation, Swedish-Norwegian family. The mutation is associated with both complete and partial deficiency in evoked AVP secretion during fluid deprivation in patients who have suffered from FNDI for decades.

Being a rapid diagnostic tool for CNDI, direct sequencing of AVPR2 should be encouraged in newborns with familial predisposition to CNDI. What is Known: • Disease-causing variants in AVPR2 cause X-linked congenital nephrogenic diabetes insipidus (CNDI). • DNA sequencing of AVPR2 is rapid, facilitates differential diagnosis, early intervention, and genetic diagnosis thus reducing morbidity in CNDI. What is New: • We identified eight novel disease-causing variants in AVPR2: p.Arg68Alafs*124, p.Ser171Arg, p.Gln174Pro, p.Trp200Arg, p.Gly201Cys, p.Gly220Arg, p.Val226Glu, and p.Gln291Pro, thereby adding to the growing list of AVPR2 disease-causing variants and emphasizing the importance of genetic testing in CNDI.

Hepatitis B (HBV) and hepatitis C (HCV) are major health burdens with more than 300 million infected individuals worldwide. While children with chronic HBV or HCV infection are thought to have a benign course, 1,2 serious liver disease can develop during childhood underlining the importance of exploring the natural disease course in order to optimise timing of treatment. 1.1 | Hepatitis B virus (HBV) Globally, 257 million people suffer from a chronic HBV infection and the estimated global prevalence is 3.5%. 3 In the European Union, the estimated prevalence of HBV is 0.9% 4 and in Denmark even lower with an estimated prevalence of 0.24% in people older than 15 years. 5 HBV caused an estimated 887 000 deaths worldwide in 2015, mostly from cirrhosis and hepatocellular carcinoma

We have recently developed a protocol for generating huge numbers of mature and functional mast cells from in vitro differentiated umbilical cord blood cells. Using CD133 as a positive selection marker to isolate haematopoietic progenitors we routinely expand the number of recovered cells at least 150‐fold, which vastly exceeds the yields of conventional protocols using CD34+ cells as a source of progenitors. Taking advantage of the large quantities of in vitro differentiated mast cells, here we assess at the levels of transcription and translation the kinetics of chemokine gene induction following receptor mediated mast cell activation or following pharmacological activation of specific signal transduction cascades that become activated upon classical FcɛRI receptor crosslinking. We demonstrate that chemokine genes encoding IL‐8, MCP‐1, MIP‐1α, and MIP‐1β are induced with different kinetics and with different amplitudes in a receptor activation dependent manner, and that these events can be mimicked using pharmacological agents which activate distinct signal transduction pathways. These findings were corroborated by adding immunomodulators such as cyclosporin A and dexamethasone prior to mast cell activation. Finally, we demonstrate that the same modulators added after mast cell activation can differentially quench ongoing chemokine gene induction. Thus, considering the vast yields of mast cells, our protocol is valuable not only for studying regulation of gene expression in mast cells in general, but also as an experimental tool to develop better and more balanced treatments of mast cell related disorders.

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The autosomal dominant familial form of neurohypophyseal diabetes insipidus (adFNDI) is a rare inherited endocrine disorder characterized by hypotonic polyuria, severe thirst and polydipsia, which results from a deficient neurosecretion of the antidiuretic hormone, also known as arginine vasopressin (AVP). To date, adFNDI has been linked to more than 70 different heterozygous point mutations of the 2.5 kb AVP gene, encoding the composite precursor protein of AVP. A minority of disease-causing mutations, such as the common c.55G>A variant, are predicted to affect amino acid residues close to the signal peptide (SP) cleavage site, and result in abnormal post-translational processing and intracellular trafficking of AVP precursors exerting neurotoxic activity on vasopressinergic magnocellular neurons. Generally, SP variants cause a gradual decline in the neurohypophyseal secretion of AVP in small children, although a wide variability in clinical onset and severity of manifestations has been reported. For the first time, we describe a kindred from Calabria (Southern Italy) with adFNDI and document a partial clinical phenotype in one female young adult member of the family. Methods: A young adult woman was subjected to clinical, neuroradiological and genetic assessments for a mild, adolescent-onset, polyuric state at our Endocrinology Unit. Her family medical history revealed an early-onset (<12 years of age) occurrence of polyuria and polydipsia, which was successfully managed with high doses of oral desmopressin, and a typical adFNDI inheritance pattern that was seen over three generations. Results: In the index patient, the extensive hypertonic dehydration during fluid deprivation test elicited a prompt elevation of urine osmolality and diuresis contraction, indicative of a partial adFNDI phenotype. Diagnosis was confirmed by concordant hormonal tests and magnetic resonance imaging (MRI) evidence of a reduced hyperintense signal of the neurohypophysis, which was regarded as compatible with the depletion of the vasopressinergic magnocellular neurons. Direct DNA sequencing and restriction enzyme cleavage analysis revealed that a heterozygous c.55G>A transition, predicting a p.Ala19Thr replacement in the C-terminal region of SP, was the cause of adFNDI in the investigated kindred. Conclusions: The identification of the genetic cause of aFNDI in this Calabrian kindred provides further information and confirms the wide variability of disease onset and severity of manifestations related to SP variants of the AVP gene, supporting the need for genetic testing in all patients with familial occurrence of polyuria, regardless of their clinical and radiological phenotype. Even though sexual differences in the antidiuretic responses are documented, it is unclear whether female gender would attenuate clinical disease progression in the presence of a pathogenic c.55G>A mutation.