Mutations in the mitochondrial cysteinyl-tRNA synthase gene, CARS2, lead to a severe epileptic encephalopathy and complex movement disorder

Background: Mitochondrial disease is often suspected in cases of severe epileptic encephalopathy especially when a complex movement disorder, liver involvement and progressive developmental regression are present. Although mutations in either mitochondrial DNA or POLG are often present, other nuclear defects in mitochondrial DNA replication and protein translation have been associated with a severe epileptic encephalopathy. Methods: and results We identified a proband with an epileptic encephalopathy, complex movement disorder and a combined mitochondrial respiratory chain enzyme deficiency. The child presented with neurological regression, complex movement disorder and intractable seizures. A combined deficiency of mitochondrial complexes I, III and IV was noted in liver tissue, along with increased mitochondrial DNA content in skeletal muscle. Incomplete assembly of complex V, using blue native polyacrylamide gel electrophoretic analysis and complex I, using western blotting, suggested a disorder of mitochondrial transcription or translation. Exome sequencing identified compound heterozygous mutations in CARS2, a mitochondrial aminoacyl-tRNA synthetase. Both mutations affect highly conserved amino acids located within the functional ligase domain of the cysteinyl-tRNA synthase. A specific decrease in the amount of charged mt-tRNACys was detected in patient fibroblasts compared with controls. Retroviral transfection of the wild-type CARS2 into patient skin fibroblasts led to the correction of the incomplete assembly of complex V, providing functional evidence for the role of CARS2 mutations in disease aetiology. Conclusions: Our findings indicate that mutations in CARS2 result in a mitochondrial translational defect as seen in individuals with mitochondrial epileptic encephalopathy

Clinical, biochemical, and genetic spectrum of seven patients with NFU1 deficiency

Disorders of the mitochondrial energy metabolism are clinically and genetically heterogeneous. An increasingly recognized subgroup is caused by defective mitochondrial iron-sulfur (Fe-S) cluster biosynthesis, with defects in 13 genes being linked to human disease to date. Mutations in three of them, NFU1, BOLA3, and IBA57, affect the assembly of mitochondrial [4Fe-4S] proteins leading to an impairment of diverse mitochondrial metabolic pathways and ATP production. Patients with defects in these three genes present with lactic acidosis, hyperglycinemia, and reduced activities of respiratory chain complexes I and II, the four lipoic acid-dependent 2-oxoacid dehydrogenases and the glycine cleavage system (GCS). To date, five different NFU1 pathogenic variants have been reported in 15 patients from 12 families. We report on seven new patients from five families carrying compound heterozygous or homozygous pathogenic NFU1 mutations identified by candidate gene screening and exome sequencing. Six out of eight different disease alleles were novel and functional studies were performed to support the pathogenicity of five of them. Characteristic clinical features included fatal infantile encephalopathy and pulmonary hypertension leading to death within the first 6 months of life in six out of seven patients. Laboratory investigations revealed combined defects of pyruvate dehydrogenase complex (five out of five) and respiratory chain complexes I and II+III (four out of five) in skeletal muscle and/or cultured skin fibroblasts as well as increased lactate (five out of six) and glycine concentration (seven out of seven). Our study contributes to a better definition of the phenotypic spectrum associated with NFU1 mutations and to the diagnostic workup of future patients

Functional and clinical studies reveal pathophysiological complexity of CLCN4-related neurodevelopmental condition

Missense and truncating variants in the X-chromosome-linked CLCN4 gene, resulting in reduced or complete loss-of-function (LOF) of the encoded chloride/proton exchanger ClC-4, were recently demonstrated to cause a neurocognitive phenotype in both males and females. Through international clinical matchmaking and interrogation of public variant databases we assembled a database of 90 rare CLCN4 missense variants in 90 families: 41 unique and 18 recurrent variants in 49 families. For 43 families, including 22 males and 33 females, we collated detailed clinical and segregation data. To confirm causality of variants and to obtain insight into disease mechanisms, we investigated the effect on electrophysiological properties of 59 of the variants in Xenopus oocytes using extended voltage and pH ranges. Detailed analyses revealed new pathophysiological mechanisms: 25% (15/59) of variants demonstrated LOF, characterized by a “shift” of the voltage-dependent activation to more positive voltages, and nine variants resulted in a toxic gain-of-function, associated with a disrupted gate allowing inward transport at negative voltages. Functional results were not always in line with in silico pathogenicity scores, highlighting the complexity of pathogenicity assessment for accurate genetic counselling. The complex neurocognitive and psychiatric manifestations of this condition, and hitherto under-recognized impacts on growth, gastrointestinal function, and motor control are discussed. Including published cases, we summarize features in 122 individuals from 67 families with CLCN4-related neurodevelopmental condition and suggest future research directions with the aim of improving the integrated care for individuals with this diagnosis

META Score: An International Consensus Scoring System on Mesh-Tissue Adhesions

Background: Currently, the lack of consensus on postoperative mesh-tissue adhesion scoring leads to incomparable scientific results. The aim of this study was to develop an adhesion score recognized by experts in the field of hernia surgery. Methods: Authors of three or more previously published articles on both mesh-tissue adhesion scores and postoperative adhesions were marked as experts. They were queried on seven items using a modified Delphi method. The items concerned the utility of adhesion scoring models, the appropriateness of macroscopic and microscopic variables, the range and use of composite scores or subscores, adhesion-related complications and follow-up length. This study comprised two questionnaire-based rounds and one consensus meeting. Results: The first round was completed by 23 experts (82%), the second round by 18 experts (64%). Of those 18 experts, ten were able to participate in the final consensus meeting and all approved the final proposal. From a total of 158 items, consensus was reached on 90 items. The amount of mesh surface covered with adhesions, tenacity and thickness of adhesions and organ involvement was concluded to be a minimal set of variables to be communicated separately in each future study on mesh adhesions. Conclusion: The MEsh Tissue Adhesion scoring system is the first consensus-based scoring system with a wide backing of renowned experts and can be used to assess mesh-related adhesions. By including this minimal set of variables in future research interstudy comparability and objectivity can be increased and eventually linked to clinically relevant outcomes

Long-term outcome of liver transplantation for unresectable liver metastases from neuroendocrine neoplasms: a Belgian retrospective multi-centre study

peer reviewedBackground: Liver transplantation (LT) is the only curative treatment for unresectable liver metastases from neuroendocrine neoplasms (NEN-Liver-Mets). While recurrence is frequent after LT, there is limited data available in the literature on the outcome of recurrent patients. Methods: We retrospectively reviewed the medical records of all patients who underwent LT by NEN-Mets at the six LT centres in Belgium from 1986 to 2020. Patient and tumour characteristics, indication for transplantation, overall survival (OS), disease-free survival (DFS), and tumour recurrence and outcomes were analysed. Results: Forty patients underwent a LT for NEN-Liver-Mets in Belgium. Twenty-nine patients were male (74.2%) with a mean age of 41.9 and 47.1 years at the time of NEN diagnosis and LT, respectively. WHO classification was available for 32 patients and changed over time (see table below). OS post-LT at 1-, 5-, and 10-years are: 84,3%, 65,0% and 54,6% respectively, while the overall DFS are: 76.3%, 44.5% and 38.2% in the same intervals. Patients transplanted after 2010 showed better OS at 5-and 10-years (74.8% and 74.8%) when compared with patients transplanted before (60,0% and 49.5%). Twenty patients (50%) presented a NEN recurrence, of this, 14 (70%) were transplanted before 2010 and only 6 (30%) were transplanted afterwards (p=0.03). The median time for recurrence diagnosis was 12.3 months (range: 5.1 to 69.2). The most frequent recurrence treatments were surgical resection, somatostatin analogs, chemotherapy, and sunitinib therapy (8, 6, 6, and 4 patients, respectively). Survival rates were 89.5% and 56.1% at 1- and 5-years after recurrence diagnosis.Conclusions: Patients transplanted for unresectable NEN-Liver metastases had good long-term survival. Although the total recurrence rate is high, it decreased dramatically after 2010, probably due to better patient selection. Furthermore, recurrence treatment should be recommended as it may prolong patient survival

Hypothermic Machine Perfusion in Liver Transplantation - A Randomized Trial

BACKGROUND Transplantation of livers obtained from donors after circulatory death is associated with an increased risk of nonanastomotic biliary strictures. Hypothermic oxygenated machine perfusion of livers may reduce the incidence of biliary complications, but data from prospective, controlled studies are limited. METHODS In this multicenter, controlled trial, we randomly assigned patients who were undergoing transplantation of a liver obtained from a donor after circulatory death to receive that liver either after hypothermic oxygenated machine perfusion (machine-perfusion group) or after conventional static cold storage alone (control group). The primary end point was the incidence of nonanastomotic biliary strictures within 6 months after transplantation. Secondary end points included other graft-related and general complications. RESULTS A total of 160 patients were enrolled, of whom 78 received a machine-perfused liver and 78 received a liver after static cold storage only (4 patients did not receive a liver in this trial). Nonanastomotic biliary strictures occurred in 6% of the patients in the machine-perfusion group and in 18% of those in the control group (risk ratio, 0.36; 95% confidence interval [CI], 0.14 to 0.94; P=0.03). Postreperfusion syndrome occurred in 12% of the recipients of a machine-perfused liver and in 27% of those in the control group (risk ratio, 0.43; 95% CI, 0.20 to 0.91). Early allograft dysfunction occurred in 26% of the machine-perfused livers, as compared with 40% of control livers (risk ratio, 0.61; 95% CI, 0.39 to 0.96). The cumulative number of treatments for nonanastomotic biliary strictures was lower by a factor of almost 4 after machine perfusion, as compared with control. The incidence of adverse events was similar in the two groups. CONCLUSIONS Hypothermic oxygenated machine perfusion led to a lower risk of nonanastomotic biliary strictures following the transplantation of livers obtained from donors after circulatory death than conventional static cold storage

Functional and clinical studies reveal pathophysiological complexity of CLCN4-related neurodevelopmental condition

Missense and truncating variants in the X-chromosome-linked CLCN4 gene, resulting in reduced or complete loss-of-function (LOF) of the encoded chloride/proton exchanger ClC-4, were recently demonstrated to cause a neurocognitive phenotype in both males and females. Through international clinical matchmaking and interrogation of public variant databases we assembled a database of 90 rare CLCN4 missense variants in 90 families: 41 unique and 18 recurrent variants in 49 families. For 43 families, including 22 males and 33 females, we collated detailed clinical and segregation data. To confirm causality of variants and to obtain insight into disease mechanisms, we investigated the effect on electrophysiological properties of 59 of the variants in Xenopus oocytes using extended voltage and pH ranges. Detailed analyses revealed new pathophysiological mechanisms: 25% (15/59) of variants demonstrated LOF, characterized by a “shift” of the voltage-dependent activation to more positive voltages, and nine variants resulted in a toxic gain-of-function, associated with a disrupted gate allowing inward transport at negative voltages. Functional results were not always in line with in silico pathogenicity scores, highlighting the complexity of pathogenicity assessment for accurate genetic counselling. The complex neurocognitive and psychiatric manifestations of this condition, and hitherto under-recognized impacts on growth, gastrointestinal function, and motor control are discussed. Including published cases, we summarize features in 122 individuals from 67 families with CLCN4-related neurodevelopmental condition and suggest future research directions with the aim of improving the integrated care for individuals with this diagnosis

Added value of 3D-vision during robotic pancreatoduodenectomy anastomoses in biotissue (LAEBOT 3D2D): a randomized controlled cross-over trial

Background: We tested the added value of 3D-vision on procedure time and surgical performance during robotic pancreatoduodenectomy anastomoses in biotissue. Robotic surgery has the advantage of articulating instruments and 3D-vision. Consensus is lacking on the added value of 3D-vision during laparoscopic surgery. Given the improved dexterity with robotic surgery, the added value of 3D-vision may be even less with robotic surgery. Methods: In this experimental randomized controlled cross-over trial, 20 surgeons and surgical residents from 5 countries performed robotic pancreaticojejunostomy and hepaticojejunostomy anastomoses in a biotissue organ model using the da Vinci® system and were randomized to start with either 3D- or 2D-vision. Primary endpoint was the time required to complete both anastomoses. Secondary endpoint was the objective structured assessment of technical skill (OSATS; range 12–60) rating; scored by two observers blinded to 3D/2D. Results: Robotic 3D-vision reduced the combined operative time from 78.1 to 57.3 min (24.6% reduction, p < 0.001; 20.8 min reduction, 95% confidence intervals 12.8–28.8 min). This reduction was consistent for both anastomoses and between surgeons and residents, p < 0.001. Robotic 3D-vision improved OSATS performance by 6.1 points (20.8% improvement, p = 0.003) compared to 2D (39.4 to 45.1 points, ± 5.5). Conclusion: 3D-vision has a considerable added value during robotic pancreatoduodenectomy anastomoses in biotissue in both time reduction and improved surgical performance as compared to 2D-vision

Performance with robotic surgery versus 3D-and 2D-laparoscopy during pancreatic and biliary anastomoses in a biotissue model: pooled analysis of two randomized trials

Background Robotic surgery may improve surgical performance during minimally invasive pancreatoduodenectomy as compared to 3D- and 2D-laparoscopy but comparative studies are lacking. This study assessed the impact of robotic surgery versus 3D- and 2D-laparoscopy on surgical performance and operative time using a standardized biotissue model for pancreatico- and hepatico-jejunostomy using pooled data from two randomized controlled crossover trials (RCTs). Methods Pooled analysis of data from two RCTs with 60 participants (36 surgeons, 24 residents) from 11 countries (December 2017-July 2019) was conducted. Each included participant completed two pancreatico- and two hepatico-jejunostomies in biotissue using 3D-robotic surgery, 3D-laparoscopy, or 2D-laparoscopy. Primary outcomes were the objective structured assessment of technical skills (OSATS: 12-60) rating, scored by observers blinded for 3D/2D and the operative time required to complete both anastomoses. Sensitivity analysis excluded participants with excess experience compared to others. Results A total of 220 anastomoses were completed (robotic 80, 3D-laparoscopy 70, 2D-laparoscopy 70). Participants in the robotic group had less surgical experience [median 1 (0-2) versus 6 years (4-12), p < 0.001], as compared to the laparoscopic group. Robotic surgery resulted in higher OSATS ratings (50, 43, 39 points, p = .021 and p < .001) and shorter operative time (56.5, 65.0, 81.5 min, p = .055 and p < .001), as compared to 3D- and 2D-laparoscopy, respectively, which remained in the sensitivity analysis. Conclusion In a pooled analysis of two RCTs in a biotissue model, robotic surgery resulted in better surgical performance scores and shorter operative time for biotissue pancreatic and biliary anastomoses, as compared to 3D- and 2D-laparoscopy.Surgical oncolog