Homozygous COQ7 mutation: a new cause of potentially treatable distal hereditary motor neuropathy.

Distal hereditary motor neuropathy represents a group of motor inherited neuropathies leading to distal weakness. We report a family of two brothers and a sister affected by distal hereditary motor neuropathy in whom a homozygous variant c.3G>T (p.1Met?) was identified in the COQ7 gene. This gene encodes a protein required for coenzyme Q10 biosynthesis, a component of the respiratory chain in mitochondria. Mutations of COQ7 were previously associated with severe multi-organ disorders characterized by early childhood onset and developmental delay. Using patient blood samples and fibroblasts derived from a skin biopsy, we investigated the pathogenicity of the variant of unknown significance c.3G>T (p.1Met?) in the COQ7 gene and the effect of coenzyme Q10 supplementation in vitro. We showed that this variation leads to a severe decrease in COQ7 protein levels in the patient's fibroblasts, resulting in a decrease in coenzyme Q10 production and in the accumulation of 6-demethoxycoenzyme Q10, the COQ7 substrate. Interestingly, such accumulation was also found in the patient's plasma. Normal coenzyme Q10 and 6-demethoxycoenzyme Q10 levels were restored in vitro by using the coenzyme Q10 precursor 2,4-dihydroxybenzoic acid, thus bypassing the COQ7 requirement. Coenzyme Q10 biosynthesis deficiency is known to impair the mitochondrial respiratory chain. Seahorse experiments showed that the patient's cells mainly rely on glycolysis to maintain sufficient ATP production. Consistently, the replacement of glucose by galactose in the culture medium of these cells reduced their proliferation rate. Interestingly, normal proliferation was restored by coenzyme Q10 supplementation of the culture medium, suggesting a therapeutic avenue for these patients. Altogether, we have identified the first example of recessive distal hereditary motor neuropathy caused by a homozygous variation in the COQ7 gene, which should thus be included in the gene panels used to diagnose peripheral inherited neuropathies. Furthermore, 6-demethoxycoenzyme Q10 accumulation in the blood can be used to confirm the pathogenic nature of the mutation. Finally, supplementation with coenzyme Q10 or derivatives should be considered to prevent the progression of COQ7-related peripheral inherited neuropathy in diagnosed patients.

Use of MFM-20 to monitor SMA types 1 and 2 patients treated with nusinersen.

OBJECTIVE: To evaluate sensitivity to change and discriminant validity of the 20-item Motor Function Measure (MFM-20) in 2-7-year-old patients with spinal muscular atrophy types 1 (SMA1) or 2 (SMA2) treated with nusinersen. METHODS: Children aged 2 to 7 years old with SMA1 or SMA2 treated with nusinersen were assessed at least three times using the MFM-20 over an average follow-up time of 17 months. Evolution of 4-month-standardized MFM-20 scores was calculated for each MFM-20 domain (D1 standing and transfers, D2 axial and proximal, D3 distal) and for the total score (TS). RESULTS: Included in the study were 22 SMA1 subjects and 19 SMA2 subjects. Baseline MFM scores were significantly lower in patients with SMA1 than SMA2 (TS 29.5% vs. 48.3%, D1 4.5% vs. 10.6%, D2 43.6% vs. 72.6%, D3 51.2% vs. 75.0%). When considering the mean change during nusinersen treatment, standardized over a 4-month period, TS was improved for both SMA1 (+ 4.1%, SRM 1.5) and SMA2 (+ 2.8%, SRM 0.89) patients. For SMA1 patients, considerable changes were observed in D2 (+ 6.2%, SRM 0.89) and D3 (+ 6.0%, SRM 0.72), whereas the change in D1 was small (+ 0.5%, SRM 0.44). In SMA2 2 subjects, D3 was improved to a larger extent (+ 4.2%, SRM 0.53) than D1 (+ 1.8% SRM 0.63) or D2 (+ 3.2%, SRM 0.69). CONCLUSION: Our results validate use of MFM-20 to monitor function of young SMA1 and SMA2 subjects treated with nusinersen. Significant motor function improvements following treatment were observed in both SMA1 and SMA2 patients.

Expanding the phenotypic variability of MORC2 gene mutations: From Charcot-Marie-Tooth disease to late-onset pure motor neuropathy.

MORC2 gene encodes a ubiquitously expressed nuclear protein involved in chromatin remodeling, DNA repair, and transcriptional regulation. Heterozygous mutations in MORC2 gene have been associated with a spectrum of disorders affecting the peripheral nervous system such as Charcot-Marie-Tooth (CMT2Z), spinal muscular atrophy-like with or without cerebellar involvement, and a developmental syndrome associated with impaired growth, craniofacial dysmorphism and axonal neuropathy (DIGFAN syndrome). Such variability in clinical manifestations associated with the increasing number of variants of unknown significance detected by next-generation sequencing constitutes a serious diagnostic challenge. Here we report the characterization of an in vitro model to evaluate the pathogenicity of variants of unknown significance based on MORC2 overexpression in a neuroblastoma cell line SH-EP or cortical neurons. Likewise, we show that MORC2 mutants affect survival and trigger apoptosis over time in SH-EP cell line. Furthermore, overexpression in primary cortical neurons increases apoptotic cell death and decreases neurite outgrowth. Altogether, these approaches establish the pathogenicity of two new variants p.Gly444Arg and p.His446Gln in three patients from two families. These new mutations in MORC2 gene are associated with autosomal dominant CMT and with adult late onset proximal motor neuropathy, further increasing the spectrum of clinical manifestations associated with MORC2 mutations.

Severe congenital myasthenic syndromes caused by agrin mutations affecting secretion by motoneurons.

Congenital myasthenic syndromes (CMS) are predominantly characterized by muscle weakness and fatigability and can be caused by a variety of mutations in genes required for neuromuscular junction formation and maintenance. Among them, AGRN encodes agrin, an essential synaptic protein secreted by motoneurons. We have identified severe CMS patients with uncharacterized p.R1671Q, p.R1698P and p.L1664P mutations in the LG2 domain of agrin. Overexpression in primary motoneurons cultures in vitro and in chick spinal motoneurons in vivo revealed that the mutations modified agrin trafficking, leading to its accumulation in the soma and/or in the axon. Expression of mutant agrins in cultured cells demonstrated accumulation of agrin in the endoplasmic reticulum associated with induction of unfolded protein response (UPR) and impaired secretion in the culture medium. Interestingly, evaluation of the specific activity of individual agrins on AChR cluster formation indicated that when secreted, mutant agrins retained a normal capacity to trigger the formation of AChR clusters. To confirm agrin accumulation and secretion defect, iPS cells were derived from a patient and differentiated into motoneurons. Patient iPS-derived motoneurons accumulated mutant agrin in the soma and increased XBP1 mRNA splicing, suggesting UPR activation. Moreover, co-cultures of patient iPS-derived motoneurons with myotubes confirmed the deficit in agrin secretion and revealed a reduction in motoneuron survival. Altogether, we report the first mutations in AGRN gene that specifically affect agrin secretion by motoneurons. Interestingly, the three patients carrying these mutations were initially suspected of spinal muscular atrophy (SMA). Therefore, in the presence of patients with a clinical presentation of SMA but without mutation in the SMN1 gene, it can be worth to look for mutations in AGRN.

Comparison of clinical outcomes and accuracy of electrode placement between robot-assisted and conventional deep brain stimulation of the subthalamic nucleus: a single-center study.

BACKGROUND: Several surgical methods are used for deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson's disease (PD). This study aimed to compare clinical outcomes and electrode placement accuracy after robot-assisted (RAS) versus frame-based stereotactic (FSS) STN DBS in Parkinson's disease. METHODS: In this single-center open-label study, we prospectively collected data from 48 consecutive PD patients who underwent RAS (Neuromate®; n = 20) or FSS (n = 28) STN DBS with the same MRI-based STN targeting between October 2016 and December 2018 in the university neurological hospital of Lyon, France. Clinical variables were assessed before and 1 year after surgery. The number of electrode contacts within the STN was determined by merging post-operative CT and pre-operative MRI using Brainlab® GUIDE™XT software. RESULTS: One year after surgery, the improvement of motor manifestations (p = 0.18), motor complications (p = 0.80), and quality of life (p= 0.30) and the reduction of dopaminergic treatment (p = 0.94) and the rate of complications (p = 0.99) were similar in the two groups. Surgery duration was longer in the RAS group (p = 0.0001). There was no difference in the number of electrode contacts within the STN. CONCLUSION: This study demonstrates that RAS and FSS STN DBS for PD provide similar clinical outcomes and accuracy of electrode placement.

Psychometric Characteristics of the Motor Function Measure in Neuromuscular Diseases: A Systematic Review1.

BACKGROUND: Recent pharmaceutical breakthroughs in neuromuscular diseases may considerably change the prognosis and natural history these diseases. The ability to measure clinically relevant outcomes such as motor function is critical for the assessment of therapeutics and the follow up of individuals. The Motor Function Measure (MFM) is a quantitative scale designed to measure motor function in adult and children with neuromuscular disease (NMD). OBJECTIVE: The objective of this study is to assess the quality and level of evidence of the MFM's published measurement properties by completing a systematic review of the validation and responsiveness studies of the MFM20 (a 20-item version of MFM adapted for children 2 to 6 years of age) and the MFM32 (the original 32 item version), in all NMDs and in specific diseases. METHODS: A search for MFM responsiveness and MFM validation studies was completed in February 2023 in EMBASE, MEDLINE, SCOPUS and Web of Science databases. The PRISMA guidelines and the COSMIN manual for systematic reviews were followed for databases searches, articles screening and selection, study quality and measurement properties evaluation. RESULTS: 49 studies were included in analysis. In studies including individuals with all NMDs, MFM's internal consistency, reliability, convergent validity, construct validity and responsiveness were rated as sufficient with a high quality of evidence. Structural validity was rated sufficient with a moderate quality of evidence In SMA in particular, MFM's reliability, internal consistency, convergent validity, discriminant validity and responsiveness are sufficient with a high quality of evidence. More studies would be required to assess specific measurement properties in different diseases. MFM32's minimal clinically relevant difference has been defined between 2 and 6%. CONCLUSION: MFM's structural validity, internal consistency, reliability, construct validity, convergent validity and responsiveness have been verified with moderate to high level of evidence.

GLUcose COntrol Safety & Efficacy in type 2 DIabetes, a systematic review and NETwork meta-analysis.

BACKGROUND: The last international consensus on the management of type 2 diabetes (T2D) recommends SGLT-2 inhibitors or GLP-1 agonists for patients with clinical cardiovascular (CV) disease; metformin remains the first-line glucose lowering medication. Last studies suggested beneficial effects of SGLT-2 inhibitors or GLP-1 agonists compared to DPP-4 inhibitors, in secondary CV prevention. Recently, a potential benefit of SGLT-2 inhibitors in primary CV prevention also has been suggested. However, no comparison of all the new and the old hypoglycemic drugs is available on CV outcomes. We aimed to compare the effects of old and new hypoglycemic drugs in T2D, on major adverse cardiovascular events (MACE) and mortality. METHODS AND FINDINGS: We conducted a systematic review and network meta-analysis of clinical trials. Randomized trials, blinded or not, assessing contemporary hypoglycemic drugs on mortality or MACE in patients with T2D, were searched for in Medline, the Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov. References screening and data extraction were done by multiple observers. Each drug was analyzed according to its therapeutic class. A random Bayesian network meta-analysis model was used. The primary outcomes were overall mortality, cardiovascular mortality, and MACE. Severe adverse events and severe hypoglycemia were also recorded. 175,966 patients in 34 trials from 1970 to 2018 were included. No trials evaluating glinides or alpha glucosidase inhibitors were found. 17 trials included a majority of patients with previous cardiovascular history, 16 trials a majority of patients without. Compared to control, SGLT-2 inhibitors were associated with a decreased risk of overall mortality (OR = 0.84 [95% CrI: 0.74; 0.95]), SGLT-2 inhibitors and GLP-1 agonists with a decreased risk of MACE (OR = 0.89 [95% CrI: 0.81; 0.98] and OR = 0.88 [95% CrI: 0.81; 0.95], respectively). Compared to DPP-4 inhibitors, SGLT-2 inhibitors were associated with a decreased risk of overall mortality (OR = 0.82 [95% CrI: 0.69; 0.98]), GLP-1 agonists with a decreased risk of MACE (OR = 0.88 [95% CrI: 0.79; 0.99]). Insulin was also associated with an increased risk of MACE compared to GLP-1 agonists (OR = 1.19 [95% CrI: 1.01; 1.42]). Insulin and sulfonylureas were associated with an increased risk of severe hypoglycemia. In the trials including a majority of patients without previous CV history, the comparisons of SGLT-2 inhibitors, metformin and control did not showed significant differences on primary outcomes. We limited our analysis at the therapeutic class level. CONCLUSIONS: SGLT-2 inhibitors and GLP-1 agonists have the most beneficial effects, especially in T2D patients with previous CV diseases. Direct comparisons of SGLT-2 inhibitors, GLP-1 agonists and metformin are needed, notably in primary CV prevention. TRIAL REGISTRATION: PROSPERO CRD42016043823.

Limited evidence of physical therapy on balance after stroke: A systematic review and meta-analysis.

BACKGROUND: Stroke results in balance disorders and these directly affect autonomy and quality of life. The purpose of this systematic review and meta-analysis was to determine the efficacy of physical therapy (PT) on balance and postural control after stroke. METHODS: We included all randomized controlled trials assessing the efficacy of PT on balance and postural control in adult patients after stroke without language restriction. Medline, Embase/Scopus, Cochrane Central Register of Controlled Trials, PEDro, Pascal, and Francis databases were searched until January 2019. Primary outcomes were balance (Berg Balance scale and Postural Assessment Scale for Stroke) and postural control with postural deviation or stability measurement in sitting or standing static evaluation. A pair of independent reviewers selected studies, extracted data, and assessed risk of bias. Meta-analyses with subgroups (categories of PT, time post-stroke, and lesion location) and meta-regression (duration of PT) were conducted. RESULTS: A total of 145 studies (n = 5912) were selected from the 13,123 records identified. For balance, evidence was found in favor of the efficacy of functional task-training alone (standardized mean difference 0.39, 95% confidence interval [0.09; 0.68], heterogeneity I2 = 63%) or associated with musculoskeletal intervention and/or cardiopulmonary intervention (0.37, [0.19; 0.55], I2 = 48%), electrostimulation (0.91, [0.49; 1.34], I2 = 52%) immediately after intervention, compared to sham treatment or usual care (ST/UC). For postural deviation eyes open, assistive devices were more effective than no treatment (-0.21, [-0.37; -0.05], I2 = 0%) immediately after intervention; for postural stability eyes open, functional task-training and sensory interventions were more effective than ST/UC (0.97, [0.35; 1.59], I2 = 65% and 0.80, [0.46; 1.13], I2 = 37% respectively) immediately after intervention. CONCLUSIONS: Functional task-training associated with musculoskeletal intervention and/or cardiopulmonary intervention and sensory interventions seem to be immediately effective in improving balance and postural stability, respectively. The heterogeneity of PT and the weak methodological quality of studies limited the interpretation and the confidence in findings.

Protocol of GLUcose COntrol Safety and Efficacy in type 2 DIabetes, a NETwork meta-analysis: GLUCOSE DINET protocol-Rational and design.

The aim of this study was to propose a ranking of the currently available antidiabetic drugs, regarding vascular clinical outcomes, in patients with type 2 diabetes, through a network meta-analysis approach. Randomized clinical trials, regardless of the blinding design, testing contemporary antidiabetic drugs, and considering clinically relevant outcomes in patients with type 2 diabetes mellitus will be included. The primary outcomes of this analysis will be overall mortality, cardiovascular mortality, and major cardiovascular events. Diabetic microangiopathy will be a secondary outcome. Adverse events, hypoglycemia, weight evolution, bariatric surgery, and discontinuation of the treatment will also be recorded. Each drug will be analyzed according to its therapeutic class: biguanide, alpha-glucosidase inhibitors, sulfonylureas, glitazones, glinides, insulin, DPP-4 inhibitors, GLP-1 analogs, and gliflozins. The treatment effect of each drug class will be compared using pairwise meta-analysis and a Bayesian random model network meta-analysis. Sensitivity analyses will be conducted according to the quality of the studies and the glycemic control. The report will follow the PRISMA checklist for network meta-analysis. Results of the search strategy and of the study selection will be presented in a PRISMA compliant flowchart. The treatment effects will be summarized with odds ratio (OR) estimates and their 95% credible intervals. A ranking of the drugs will be proposed. Our network meta-analysis should allow a clinically relevant ranking of the contemporary antidiabetic drugs.