Hereditary sensory and autonomic neuropathies: types II, III, and IV

The hereditary sensory and autonomic neuropathies (HSAN) encompass a number of inherited disorders that are associated with sensory dysfunction (depressed reflexes, altered pain and temperature perception) and varying degrees of autonomic dysfunction (gastroesophageal reflux, postural hypotention, excessive sweating). Subsequent to the numerical classification of four distinct forms of HSAN that was proposed by Dyck and Ohta, additional entities continue to be described, so that identification and classification are ongoing. As a group, the HSAN are rare diseases that affect both sexes. HSAN III is almost exclusive to individuals of Eastern European Jewish extraction, with incidence of 1 per 3600 live births. Several hundred cases with HSAN IV have been reported. The worldwide prevalence of HSAN type II is very low. This review focuses on the description of three of the disorders, HSAN II through IV, that are characterized by autosomal recessive inheritance and onset at birth. These three forms of HSAN have been the most intensively studied, especially familial dysautonomia (Riley-Day syndrome or HSAN III), which is often used as a prototype for comparison to the other HSAN. Each HSAN disorder is likely caused by different genetic errors that affect specific aspects of small fiber neurodevelopment, which result in variable phenotypic expression. As genetic tests are routinely used for diagnostic confirmation of HSAN III only, other means of differentiating between the disorders is necessary. Diagnosis is based on the clinical features, the degree of both sensory and autonomic dysfunction, and biochemical evaluations, with pathologic examinations serving to further confirm differences. Treatments for all these disorders are supportive

Olfactory Stem Cells, a New Cellular Model for Studying Molecular Mechanisms Underlying Familial Dysautonomia

International audienceBackground: Familial dysautonomia (FD) is a hereditary neuropathy caused by mutations in the IKBKAP gene, the most common of which results in variable tissue-specific mRNA splicing with skipping of exon 20. Defective splicing is especially severe in nervous tissue, leading to incomplete development and progressive degeneration of sensory and autonomic neurons. The specificity of neuron loss in FD is poorly understood due to the lack of an appropriate model system. To better understand and modelize the molecular mechanisms of IKBKAP mRNA splicing, we collected human olfactory ecto-mesenchymal stem cells (hOE-MSC) from FD patients. hOE-MSCs have a pluripotent ability to differentiate into various cell lineages, including neurons and glial cells.Methodology/Principal Findings: We confirmed IKBKAP mRNA alternative splicing in FD hOE-MSCs and identified 2 novel spliced isoforms also present in control cells. We observed a significant lower expression of both IKBKAP transcript and IKAP/hELP1 protein in FD cells resulting from the degradation of the transcript isoform skipping exon 20. We localized IKAP/hELP1 in different cell compartments, including the nucleus, which supports multiple roles for that protein. We also investigated cellular pathways altered in FD, at the genome-wide level, and confirmed that cell migration and cytoskeleton reorganization were among the processes altered in FD. Indeed, FD hOE-MSCs exhibit impaired migration compared to control cells. Moreover, we showed that kinetin improved exon 20 inclusion and restores a normal level of IKAP/hELP1 in FD hOE-MSCs. Furthermore, we were able to modify the IKBKAP splicing ratio in FD hOE-MSCs, increasing or reducing the WT (exon 20 inclusion):MU (exon 20 skipping) ratio respectively, either by producing free-floating spheres, or by inducing cells into neural differentiation.Conclusions/Significance: hOE-MSCs isolated from FD patients represent a new approach for modeling FD to better understand genetic expression and possible therapeutic approaches. This model could also be applied to other neurological genetic diseases

Phosphatidylserine Increases IKBKAP Levels in Familial Dysautonomia Cells

Familial Dysautonomia (FD) is an autosomal recessive congenital neuropathy that results from abnormal development and progressive degeneration of the sensory and autonomic nervous system. The mutation observed in almost all FD patients is a point mutation at position 6 of intron 20 of the IKBKAP gene; this gene encodes the IκB kinase complex-associated protein (IKAP). The mutation results in a tissue-specific splicing defect: Exon 20 is skipped, leading to reduced IKAP protein expression. Here we show that phosphatidylserine (PS), an FDA-approved food supplement, increased IKAP mRNA levels in cells derived from FD patients. Long-term treatment with PS led to a significant increase in IKAP protein levels in these cells. A conjugate of PS and an omega-3 fatty acid also increased IKAP mRNA levels. Furthermore, PS treatment released FD cells from cell cycle arrest and up-regulated a significant number of genes involved in cell cycle regulation. Our results suggest that PS has potential for use as a therapeutic agent for FD. Understanding its mechanism of action may reveal the mechanism underlying the FD disease

Outcomes following small bowel obstruction due to malignancy in the national audit of small bowel obstruction

Introduction Patients with cancer who develop small bowel obstruction are at high risk of malnutrition and morbidity following compromise of gastrointestinal tract continuity. This study aimed to characterise current management and outcomes following malignant small bowel obstruction. Methods A prospective, multicentre cohort study of patients with small bowel obstruction who presented to UK hospitals between 16th January and 13th March 2017. Patients who presented with small bowel obstruction due to primary tumours of the intestine (excluding left-sided colonic tumours) or disseminated intra-abdominal malignancy were included. Outcomes included 30-day mortality and in-hospital complications. Cox-proportional hazards models were used to generate adjusted effects estimates, which are presented as hazard ratios (HR) alongside the corresponding 95% confidence interval (95% CI). The threshold for statistical significance was set at the level of P ≤ 0.05 a-priori. Results 205 patients with malignant small bowel obstruction presented to emergency surgery services during the study period. Of these patients, 50 had obstruction due to right sided colon cancer, 143 due to disseminated intraabdominal malignancy, 10 had primary tumours of the small bowel and 2 patients had gastrointestinal stromal tumours. In total 100 out of 205 patients underwent a surgical intervention for obstruction. 30-day in-hospital mortality rate was 11.3% for those with primary tumours and 19.6% for those with disseminated malignancy. Severe risk of malnutrition was an independent predictor for poor mortality in this cohort (adjusted HR 16.18, 95% CI 1.86 to 140.84, p = 0.012). Patients with right-sided colon cancer had high rates of morbidity. Conclusions Mortality rates were high in patients with disseminated malignancy and in those with right sided colon cancer. Further research should identify optimal management strategy to reduce morbidity for these patient groups