Genetic and functional analyses of SHANK2 mutations suggest a multiple hit model of autism spectrum disorders.

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders with a complex inheritance pattern. While many rare variants in synaptic proteins have been identified in patients with ASD, little is known about their effects at the synapse and their interactions with other genetic variations. Here, following the discovery of two de novo SHANK2 deletions by the Autism Genome Project, we identified a novel 421 kb de novo SHANK2 deletion in a patient with autism. We then sequenced SHANK2 in 455 patients with ASD and 431 controls and integrated these results with those reported by Berkel et al. 2010 (n = 396 patients and n = 659 controls). We observed a significant enrichment of variants affecting conserved amino acids in 29 of 851 (3.4%) patients and in 16 of 1,090 (1.5%) controls (P = 0.004, OR = 2.37, 95% CI = 1.23-4.70). In neuronal cell cultures, the variants identified in patients were associated with a reduced synaptic density at dendrites compared to the variants only detected in controls (P = 0.0013). Interestingly, the three patients with de novo SHANK2 deletions also carried inherited CNVs at 15q11-q13 previously associated with neuropsychiatric disorders. In two cases, the nicotinic receptor CHRNA7 was duplicated and in one case the synaptic translation repressor CYFIP1 was deleted. These results strengthen the role of synaptic gene dysfunction in ASD but also highlight the presence of putative modifier genes, which is in keeping with the "multiple hit model" for ASD. A better knowledge of these genetic interactions will be necessary to understand the complex inheritance pattern of ASD.

Randomized investigation of the MitraClip device in heart failure: Design and rationale of the RESHAPE-HF2 trial design.

AIMS: The safety and effectiveness of the MitraClip device to treat functional mitral regurgitation (FMR) has been tested in previous clinical trials yielding somewhat heterogeneous results in heart failure (HF) patients. Over time, the MitraClip device system has been modified and clinical practice evolved to consider also less severely diseased HF patients with FMR for this therapeutic option. The RESHAPE-HF2 trial aims to assess the safety and effectiveness of the MitraClip device system on top of medical therapy considered optimal in the treatment of clinically significant FMR in symptomatic patients with chronic HF. METHODS: The RESHAPE-HF2 is an investigator-initiated, prospective, randomized, parallel-controlled, multicentre trial designed to evaluate the use of the MitraClip device (used in the most up-to-date version as available at sites) plus optimal standard of care therapy (device group) compared to optimal standard of care therapy alone (control group). Eligible subjects have signs and symptoms of HF (New York Heart Association [NYHA] class II-IV despite optimal therapy), and have moderate-to-severe or severe FMR, as confirmed by a central echocardiography core laboratory; have an ejection fraction between ≥20% and ≤50% (initially 15-35% for NYHA class II patients, and 15-45% for NYHA class III/IV patients); have been adequately treated per applicable standards, and have received appropriate revascularization and cardiac resynchronization therapy, if eligible; had a HF hospitalization or elevated natriuretic peptides (B-type natriuretic peptide [BNP] ≥300 pg/ml or N-terminal proBNP ≥1000 pg/ml) in the last 90 days; and in whom isolated mitral valve surgery is not a recommended treatment option. The trial has three primary endpoints, which are these: (i) the composite rate of total (first and recurrent) HF hospitalizations and cardiovascular death during 24 months of follow-up, (ii) the rate of total (i.e. first and recurrent) HF hospitalizations within 24 months, and (iii) the change from baseline to 12 months in the Kansas City Cardiomyopathy Questionnaire overall score. The three primary endpoints will be analysed using the Hochberg procedure to control the familywise type I error rate across the three hypotheses. CONCLUSIONS: The RESHAPE-HF2 trial will provide sound evidence on the MitraClip device and its effects in HF patients with FMR. The recruitment was recently completed with 506 randomized patients.

Percutaneous repair of moderate-to-severe or severe functional mitral regurgitation in patients with symptomatic heart failure: Baseline characteristics of patients in the RESHAPE-HF2 trial and comparison to COAPT and MITRA-FR trials.

AIM: The RESHAPE-HF2 trial is designed to assess the efficacy and safety of the MitraClip device system for the treatment of clinically important functional mitral regurgitation (FMR) in patients with heart failure (HF). This report describes the baseline characteristics of patients enrolled in the RESHAPE-HF2 trial compared to those enrolled in the COAPT and MITRA-FR trials. METHODS AND RESULTS: The RESHAPE-HF2 study is an investigator-initiated, prospective, randomized, multicentre trial including patients with symptomatic HF, a left ventricular ejection fraction (LVEF) between 20% and 50% with moderate-to-severe or severe FMR, for whom isolated mitral valve surgery was not recommended. Patients were randomized 1:1 to a strategy of delivering or withholding MitraClip. Of 506 patients randomized, the mean age of the patients was 70 ± 10 years, and 99 of them (20%) were women. The median EuroSCORE II was 5.3 (2.8-9.0) and median plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) was 2745 (1407-5385) pg/ml. Most patients were prescribed beta-blockers (96%), diuretics (96%), angiotensin-converting enzyme inhibitors/angiotensin receptor blockers/angiotensin receptor-neprilysin inhibitors (82%) and mineralocorticoid receptor antagonists (82%). The use of sodium-glucose cotransporter 2 inhibitors was rare (7%). Cardiac resynchronization therapy (CRT) devices had been previously implanted in 29% of patients. Mean LVEF, left ventricular end-diastolic volume and effective regurgitant orifice area (EROA) were 31 ± 8%, 211 ± 76 ml and 0.25 ± 0.08 cm2, respectively, whereas 44% of patients had mitral regurgitation severity of grade 4+. Compared to patients enrolled in COAPT and MITRA-FR, those enrolled in RESHAPE-HF2 were less likely to have mitral regurgitation grade 4+ and, on average, HAD lower EROA, and plasma NT-proBNP and higher estimated glomerular filtration rate, but otherwise had similar age, comorbidities, CRT therapy and LVEF. CONCLUSION: Patients enrolled in RESHAPE-HF2 represent a third distinct population where MitraClip was tested in, that is one mainly comprising of patients with moderate-to-severe FMR instead of only severe FMR, as enrolled in the COAPT and MITRA-FR trials. The results of RESHAPE-HF2 will provide crucial insights regarding broader application of the transcatheter edge-to-edge repair procedure in clinical practice.

The dynactin p150 subunit: cell biology studies of sequence changes found in ALS/MND and Parkinsonian syndromes.

The dynactin p150glued subunit, encoded by the gene DCTN1 is part of the dynein-dynactin motor protein complex responsible for retrograde axonal transport. This subunit is a candidate modifier for neurodegenerative diseases, in particular motoneuron and extrapyramidal diseases. Based on an extensive screening effort of all 32 exons in more than 2,500 ALS/MND patients, patients suffering from Parkinsonian Syndromes and controls, we investigated 24 sequence variants of p150 in cell-based studies. We used both non-neuronal cell lines and primary rodent spinal motoneurons and report on cell biological abnormalities in five of these sequence alterations and also briefly report on the clinical features. Our results suggest the presence of biological changes caused by some p150 mutants pointing to a potential pathogenetic significance as modifier of the phenotype of the human disease.

Transcranial versus Direct Cortical Stimulation for Motor-Evoked Potentials during Resection of Supratentorial Tumors under General Anesthesia (The TRANSEKT-Trial): Study Protocol for a Randomized Controlled Trial.

BACKGROUND: Monitoring of motor function during surgery for supratentorial tumors under general anesthesia applies either transcranial electrical stimulation (TES) or direct cortical stimulation (DCS) to elicit motor-evoked potentials. To date, there is no guideline that favor one method over the other. Therefore, we designed this randomized study to compare between both methods regarding the prediction of postoperative motor deficits and extent of tumor resection. METHODS: This is a multicenter (six centers in Germany and one in Switzerland), double blind, parallel group, exploratory, randomized controlled clinical trial. Patients without or with mild paresis, who are scheduled for surgical resection of motor-eloquent brain tumors under general anesthesia will be randomized to surgical resection under TES or surgical resection under DCS. The primary endpoint is sensitivity and specificity in prognosis of motor function 7 days after surgery. The main secondary endpoint is the extent of tumor resection. The study is planned to include 120 patients within 2 years. DISCUSSION: The present exploratory study should compare TES and DCS regarding sensitivity and specificity in predicting postoperative motor deficit and extent of tumor resection to calculate the required number of patients in a confirmatory trial to test the superiority of one method over the other.

Heterogeneous nuclear ribonucleoprotein k interacts with Abi-1 at postsynaptic sites and modulates dendritic spine morphology.

BACKGROUND: Abelson-interacting protein 1 (Abi-1) plays an important role for dendritic branching and synapse formation in the central nervous system. It is localized at the postsynaptic density (PSD) and rapidly translocates to the nucleus upon synaptic stimulation. At PSDs Abi-1 is in a complex with several other proteins including WASP/WAVE or cortactin thereby regulating the actin cytoskeleton via the Arp 2/3 complex. PRINCIPAL FINDINGS: We identified heterogeneous nuclear ribonucleoprotein K (hnRNPK), a 65 kDa ssDNA/RNA-binding-protein that is involved in multiple intracellular signaling cascades, as a binding partner of Abi-1 at postsynaptic sites. The interaction with the Abi-1 SH3 domain is mediated by the hnRNPK-interaction (KI) domain. We further show that during brain development, hnRNPK expression becomes more and more restricted to granule cells of the cerebellum and hippocampal neurons where it localizes in the cell nucleus as well as in the spine/dendritic compartment. The downregulation of hnRNPK in cultured hippocampal neurons by RNAi results in an enlarged dendritic tree and a significant increase in filopodia formation. This is accompanied by a decrease in the number of mature synapses. Both effects therefore mimic the neuronal morphology after downregulation of Abi-1 mRNA in neurons. CONCLUSIONS: Our findings demonstrate a novel interplay between hnRNPK and Abi-1 in the nucleus and at synaptic sites and show obvious similarities regarding both protein knockdown phenotypes. This indicates that hnRNPK and Abi-1 act synergistic in a multiprotein complex that regulates the crucial balance between filopodia formation and synaptic maturation in neurons.