Ultrasound assisted versus landmark based intrathecal administration of nusinersen in adults with spinal muscular atrophy disease: A randomized trial.

INTRODUCTION/AIMS: Nusinersen intrathecal administration can be challenging in spinal muscular atrophy (SMA) adults. We aimed to determine if the ultrasound (US)-assistance reduces the number of needle attempts and needle redirections needed for intrathecal drug administration and its impact on the procedure time, the incidence of adverse events (AEs), and patient satisfaction in these patients. METHODS: Fifty-eight patients aged 18 years and older scheduled for intrathecal nusinersen injection were enrolled and randomized (1:1 ratio) into Group 1 (nusinersen infusion with US-assisted technique) or Group 2 (nusinersen infusion with landmark-based technique). The number of attempts, number of redirections, periprocedural time, AEs and patient satisfaction were reported. Continuous variables were compared with the Student t-test or Wilcoxon rank sum test. Categorical variables were evaluated with the Chi-square test or Fisher's exact test in case of expected frequencies <5. The p-values <.05 were considered statistically significant. RESULTS: There were no statistical differences in the number of attempts, AEs, or patient satisfaction between the two groups. The number of needle redirections was significantly lower in the ultrasound group versus landmark-based group (p < .05) in both the overall group of patients and in the subgroup with difficult spines. The periprocedural time was about 40 seconds longer in US-group versus landmark-based group (p < .05). DISCUSSION: In SMA adults, US assistance reduces the number of needle redirections needed for intrathecal drug administration. These results suggest that the US assistance may be advantageous for nusinersen therapy to reduce the therapeutic burden of intrathecal infusion.

Clinical and genetic features of CMT2T in Italian patients confirm the importance of MME pathogenic variants in idiopathic, late-onset axonal neuropathies.

BACKGROUND AND AIMS: Since 2016, biallelic mutations in the membrane metalloendopeptidase (MME) gene have been associated with late-onset recessive CMT2 (CMT2T). More recently, heterozygous mutations have also been identified in familial and sporadic patients with late-onset axonal neuropathy, ranging from subclinical to severe. This indicates that the heterozygous MME variants may not be fully penetrant, or alternatively, that they may be a potential risk factor for neuropathy. Here, we describe the clinical, neurophysiological, and genetic findings of 32 CM2T Italian patients. METHODS: The patients were recruited from four different Italian referral centers. Following a comprehensive battery of neurological, electrophysiological, and laboratory examinations, the patients' DNA was subjected to sequencing in order to identify any variants in the gene. Bioinformatic and modeling analyses were performed to evaluate the identified variants' effects. RESULTS: We observe a relatively mild axonal sensory-motor neuropathy with a greater impairment of the lower extremities. Biallelic and monoallelic patients exhibit comparable disease severity, with an earlier onset observed in those with biallelic variants. When considering a subgroup with more than 10 years of disease, it becomes evident that biallelic patients exhibit a more severe form of neuropathy. This suggests that they are more prone to quick progression. INTERPRETATION: CM2T has been definitively defined as a late-onset neuropathy, with a typical onset in the fifth to sixth decades of life and a more rapidly progressing worsening for biallelic patients. CMT2T can be included in the neuropathies of the elderly, particularly if MME variants heterozygous patients are included.

Central venous catheter-related thrombosis in patients with amyotrophic lateral sclerosis.

BACKGROUND: Central venous catheterization may be required in patients with amyotrophic lateral sclerosis (ALS) for parenteral nutrition, antibiotic treatment, or blood sampling. Different venous access devices can be taken into consideration-centrally inserted central catheters (CICC), peripherally inserted central catheters (PICC), and femorally inserted central catheters (FICCs)-depending on the clinical conditions of the patients. Regardless of the type of access, the presence of paraplegia or tetraplegia is commonly considered a risk factor for catheter-related thrombosis (CRT). METHOD: This retrospective study analyzes the rate of CRT and other non-infectious complications associated with central venous access in a cohort of 115 patients with paraplegia or tetraplegia, most of them affected by ALS (n = 109). RESULTS: In a period of 34 months, from January 2021 to October 2023, we inserted 75 FICCs, 29 CICCs, and 11 PICCs. PICCs were inserted only in patients with preserved motility of the upper limbs. All devices were inserted by trained operators adopting appropriate insertion bundles. We had no immediate or early complication. Though antithrombotic prophylaxis was adopted only in 61.7% of patients, we had no symptomatic CRT. Other non-infectious complications were infrequent (4 out of 115 patients). CONCLUSION: These results suggest (a) that the presence of paraplegia or tetraplegia is not necessarily associated with an increased risk of CRT, (b) that the adoption of well-designed insertion bundles plays a key role in minimizing non-infectious complications, and (c) that the insertion of FICCs by direct cannulation of the superficial femoral vein at mid-thigh in paraplegic/tetraplegic patients may have the same advantages which have been described in the general population.

M6A reduction relieves FUS-associated ALS granules.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease due to gradual motoneurons (MN) degeneration. Among the processes associated to ALS pathogenesis, there is the formation of cytoplasmic inclusions produced by aggregation of mutant proteins, among which the RNA binding protein FUS. Here we show that, in neuronal cells and in iPSC-derived MN expressing mutant FUS, such inclusions are significantly reduced in number and dissolve faster when the RNA m6A content is diminished. Interestingly, stress granules formed in ALS conditions showed a distinctive transcriptome with respect to control cells, which reverted to similar to control after m6A downregulation. Notably, cells expressing mutant FUS were characterized by higher m6A levels suggesting a possible link between m6A homeostasis and pathological aggregates. Finally, we show that FUS inclusions are reduced also in patient-derived fibroblasts treated with STM-2457, an inhibitor of METTL3 activity, paving the way for its possible use for counteracting aggregate formation in ALS.

Long-term treatment of SOD1 ALS with tofersen: a multicentre experience in 17 patients.

BACKGROUND: In Amyotrophic Lateral Sclerosis (ALS) patients with SOD1 mutation the intrathecal administration of tofersen slowed down the progression of disease in a controlled clinical study, but results were not statistically significant. METHODS: In this multicentre, observational study, we evaluated a cohort of 27 ALS-SOD1 patients who were treated with tofersen, focussing on 17 patients who were followed for at least 48 weeks (median period of 84 weeks, range 48-108). We compared the clinical slopes, as measured by ALSFRS-R, MRC scale and Forced Vital Capacity, during tofersen treatment with retrospective data at 1 year prior to therapy. Cerebrospinal fluid (CSF) and serum neurofilament light chains (NFL) were measured in all patients. RESULTS: Cumulative evaluation of the ALSFRS-R and MRC progression rates showed a statistically significant change during treatment with respect to the period prior to therapy (p = 0.023 and p = 0.007, respectively). The analysis of individual patients showed that nine of the seventeen patients substantially stabilized or slightly improved. Four patients deteriorated during treatment, while in the remaining patients the very slow course did not allow to identify significant changes. CSF and serum NFL concentration markedly decreased in the near totality of patients. Increased levels of white blood cells and proteins in the CSF were found in 60% of patients. Such alterations were clinically asymptomatic in all but two patients who showed an acute pure motor radiculitis, which responded to steroid therapy. CONCLUSIONS: Clinical findings and NFL analysis strongly suggest that tofersen may have a disease-modifying effect in a subset of SOD1-ALS patients.

Hospital admissions from the emergency department of adult patients affected by myopathies.

BACKGROUND AND PURPOSE: Myopathies are associated with classic signs and symptoms, but also with possible life-threatening complications that may require assistance in an emergency setting. This phenomenon is understudied in the literature. We aimed to assess the presentation, management, and outcomes of clinical manifestations potentially related to a muscle disorder requiring referral to the adult emergency department (ED) and hospitalization. METHODS: Anonymized patient data retrieved using the International Classification of Diseases, Ninth Revision codes related to muscle disorders over 4 years were retrospectively analyzed. Medical reports were evaluated to extract demographic and clinical variables, along with outcomes. Two groups were defined based on the presence (known diagnosis [KD] group) or absence (unknown diagnosis [UD] group) of a diagnosed muscle disorder at arrival. RESULTS: A total of 244 patients were included, 51% of whom were affected by a known myopathy, predominantly limb-girdle muscular dystrophies and myotonic dystrophies. The main reasons for ED visits in the KD group were respiratory issues, worsening of muscle weakness, and gastrointestinal problems. Heart complications were less prevalent. In the UD group, 27 patients received a new diagnosis of a specific primary muscle disorder after the ED access, mostly an inflammatory myopathy. Death during hospitalization was recorded in 26 patients, with a higher rate in the KD group and in patients affected by mitochondrial and inflammatory myopathies. Sepsis and dyspnea were associated with increased death risk. CONCLUSIONS: Respiratory complications are the most common reason for myopathic patients accessing the ED, followed by gastrointestinal issues. Infections are severe threats and, once hospitalized, these patients have relatively high mortality.

Rare ACTN2 Frameshift Variants Resulting in Protein Extension Cause Distal Myopathy and Hypertrophic Cardiomyopathy through Protein Aggregation.

Distal myopathies are a group of rare, inherited muscular disorders characterized by progressive loss of muscle fibers that begins in the distal parts of arms and legs. Recently, variants in a new disease gene, ACTN2 , have been shown to cause distal myopathy. ACTN2 , a gene previously only associated with cardiomyopathies, encodes alpha-actinin-2, a protein expressed in both cardiac and skeletal sarcomeres. The primary function of alpha-actinin-2 is to link actin and titin to the sarcomere Z-disk. New ACTN2 variants are continuously discovered, however, the clinical significance of many variants remains unknown. Thus, lack of clear genotype-phenotype correlations in ACTN2 -related diseases, actininopathies, persists. Objective: The objective of the study is to characterize the pathomechanisms underlying actininopathies. Methods: Functional characterization in C2C12 cell models of several ACTN2 variants is conducted, including frameshift and missense variants associated with dominant actininopathies. We assess the genotype-phenotype correlations of actininopathies using clinical data from several patients carrying these variants. Results: The results show that the missense variants associated with a recessive form of actininopathy do not cause detectable alpha-actinin-2 aggregates in the cell model. Conversely, dominant frameshift variants causing a protein extension do produce alpha-actinin-2 aggregates. Interpretation: The results suggest that alpha-actinin-2 aggregation is the disease mechanism underlying some dominant actininopathies, and thus we recommend that protein-extending frameshift variants in ACTN2 should be classified as pathogenic. However, this mechanism is likely elicited by only a limited number of variants. Alternative functional characterization methods should be explored to further investigate other molecular mechanisms underlying actininopathies.

Early detection of nerve involvement in presymptomatic TTR mutation carriers: exploring potential markers of disease onset.

BACKGROUND: Hereditary transthyretin (ATTRv) amyloidosis is a heterogeneous, progressive, multisystemic disease with a life-threatening course if left untreated. Given the current availability of effective therapies, close follow-up of presymptomatic TTR mutation carriers is essential to recognize disease onset at the earliest sign. In addition to routine techniques, in recent years several novel tools have been proposed, although a consensus on their use has not been reached yet. In this paper, we aimed to evaluate possible markers of neuropathic disease onset intended to discriminate clinically asymptomatic carriers from early symptomatic patients, thus allowing timely treatment initiation. METHODS: Thirty-eight presymptomatic carriers were enrolled. Clinical and electrophysiological findings at first evaluation and follow-up were collected. All carriers underwent an extensive clinical and instrumental evaluation according to the standard clinical practice. One or more non-routine investigations, whose use in this field is not yet validated (henceforth "unconventional"), were additionally assessed in a subgroup of individuals. RESULTS: Based on the exclusive use of routine investigations, it was possible to define disease onset in 4/38 carriers during the follow-up. Employing additionally one or more "unconventional" tests, abnormal findings, indicative of a possible "conversion" to symptomatic disease, were detected in further 12 cases. More than half of our study cohort showed findings suggestive of small nerve fiber (SF) involvement at either invasive or non-invasive tests. CONCLUSIONS: A close, multidisciplinary monitoring of presymptomatic TTR mutation carriers is fundamental, and diagnostic workup should include both routine and "unconventional" tests. Assessment of SF involvement is important also in non-endemic countries.

Muscle magnetic resonance imaging of a large cohort of distal hereditary motor neuropathies reveals characteristic features useful for diagnosis.

Distal motor neuropathies (dHMN) are an heterogenous group of diseases characterized by progressive muscle weakness affecting predominantly the distal muscles of the lower and upper limbs. Our aim was to study the imaging features and pattern of muscle involvement in muscle magnetic resonance imaging (MRI) in dHMN patients of suspected genetic origin (dHMN). We conducted a retrospective study collecting clinical, genetic and muscle imaging data. Muscle MRI included T1-weighted and T2 weighted Short Tau Inversion Recovery images (STIR-T2w) sequences. Muscle replacement by fat was quantified using the Mercuri score. Identification of selective patterns of involvement was performed using hierarchical clustering. Eighty-four patients with diagnosis of dHMN were studied. Fat replacement was predominant in the distal lower leg muscles (82/84 cases), although also affected thigh and pelvis muscles. Asymmetric involvement was present in 29% of patients. The superficial posterior compartment of the leg, including the soleus and gastrocnemius muscles, was the most affected area (77/84). We observed a reticular pattern of fatty replacement progressing towards what is commonly known as "muscle islands" in 79.8%. Hyperintensities in STIR-T2w were observed in 78.6% patients mainly in distal leg muscles. Besides features common to all individuals, we identified and describe a pattern of muscle fat replacement characteristic of BICD2, HSPB1 and DYNC1H1 patients. We conclude that muscle MRI of patients with suspected dHMN reveals common features helpful in diagnosis process.

Clinical Classification of Variants in the Valosin-Containing Protein Gene Associated With Multisystem Proteinopathy.

Background and Objectives: Pathogenic variants in the valosin-containing protein (VCP) gene cause a phenotypically heterogeneous disorder that includes myopathy, motor neuron disease, Paget disease of the bone, frontotemporal dementia, and parkinsonism termed multisystem proteinopathy. This hallmark pleiotropy makes the classification of novel VCP variants challenging. This retrospective study describes and assesses the effect of 19 novel or nonpreviously clinically characterized VCP variants identified in 28 patients (26 unrelated families) in the retrospective VCP International Multicenter Study. Methods: A 6-item clinical score was developed to evaluate the phenotypic level of evidence to support the pathogenicity of the novel variants. Each item is allocated a value, a score ranging from 0.5 to 5.5 points. A receiver-operating characteristic curve was used to identify a cutoff value of 3 to consider a variant as high likelihood disease associated. The scoring system results were confronted with results of in vitro ATPase activity assays and with in silico analysis. Results: All variants were missense, except for one small deletion-insertion, 18 led to amino acid changes within the N and D1 domains, and 13 increased the enzymatic activity. The clinical score coincided with the functional studies in 17 of 19 variants and with the in silico analysis in 12 of 19. For 12 variants, the 3 predictive tools agreed, and for 7 variants, the predictive tools disagreed. The pooled data supported the pathogenicity of 13 of 19 novel VCP variants identified in the study. Discussion: This study provides data to support pathogenicity of 14 of 19 novel VCP variants and provides guidance for clinicians in the evaluation of novel variants in the VCP gene.

Characterization of SOD1-DT, a Divergent Long Non-Coding RNA in the Locus of the SOD1 Human Gene.

Researchers studying Amyotrophic Lateral Sclerosis (ALS) have made significant efforts to find a unique mechanism to explain the etiopathology of the different forms of the disease. However, despite several mutations associated with ALS having been discovered in recent years, the link between the mutated genes and its onset has not yet been fully elucidated. Among the genes associated with ALS, superoxide dismutase 1 (SOD1) was the first to be identified, but its role in the etiopathogenesis of the disease is still unclear. In recent years, research has been focused on the non-coding part of the genome to fully understand the mechanisms underlying gene regulation. Non-coding RNAs are conserved molecules and are not usually translated in protein. A total of 98% of the human genome is composed of non-protein coding sequences with roles in the transcriptional and post-transcriptional regulation of gene expression. In this study, we characterized a divergent nuclear lncRNA (SOD1-DT) transcribed in the antisense direction from the 5' region of the SOD1 coding gene in both the SH-SY5Y cell line and fibroblasts derived from ALS patients. Interestingly, this lncRNA seems to regulate gene expression, since its inhibition leads to the upregulation of surrounding genes including SOD1. SOD1-DT represents a very complex molecule, displaying allelic and transcriptional variability concerning transposable elements (TEs) included in its sequence, widening the scenario of gene expression regulation in ALS disease.

The HFE p.H63D (p.His63Asp) Polymorphism Is a Modifier of ALS Outcome in Italian and French Patients with SOD1 Mutations.

Background: Data from published studies about the effect of HFE polymorphisms on ALS risk, phenotype, and survival are still inconclusive. We aimed at evaluating whether the p.H63D polymorphism is a modifier of phenotype and survival in SOD1-mutated patients. Methods: We included 183 SOD1-mutated ALS patients. Mutations were classified as severe or mild according to the median survival of the study population. Patients were screened for the HFE p.H63D polymorphism. Survival was calculated using the Kaplan-Meier modeling, and differences were measured by the log-rank test. Multivariable analysis was performed with the Cox proportional hazards model (stepwise backward). Results: SOD1 severe mutation carriers show more frequent familial history for ALS and shorter survival compared to mild mutation carriers. Carriers and non-carriers of the p.H63D polymorphism did not differ in terms of sex ratio, frequency of positive familial history, age at onset, and bulbar/spinal ratio. In univariate and in Cox multivariable analysis using sex, age at onset, site of onset, family history, country of origin, and mutation severity as covariates, p.H63D carriers had a longer survival (p = 0.034 and p = 0.004). Conclusions: We found that SOD1-mutated ALS patients carrying the p.H63D HFE polymorphism have a longer survival compared to non-carriers, independently of sex, age and site of onset, family history, nation of origin, and severity of mutations, suggesting a possible role as disease progression modifier for the p.H63D HFE polymorphism in SOD1-ALS.

Evaluating the contribution of the gene TARDBP in Italian patients with amyotrophic lateral sclerosis.

BACKGROUND AND OBJECTIVES: Genetic variants in the gene TARDBP, encoding TDP-43 protein, are associated with amyotrophic lateral sclerosis (ALS) in familial (fALS) and sporadic (sALS) cases. Objectives of this study were to assess the contribution of TARDBP in a large cohort of Italian ALS patients, to determine the TARDBP-associated clinical features and to look for genotype-phenotype correlation and penetrance of the mutations. METHODS: A total of 1992 Italian ALS patients (193 fALS and 1799 sALS) were enrolled in this study. Sanger sequencing of TARDBP gene was performed in patients and, when available, in patients' relatives. RESULTS: In total, 13 different rare variants were identified in 43 index cases (10 fALS and 33 sALS) with a cumulative mutational frequency of 2.2% (5.2% of fALS, 1.8% of sALS). The most prevalent variant was the p.A382T followed by the p.G294V. Cognitive impairment was detected in almost 30% of patients. While some variants, including the p.G294V and the p.G376D, were associated with restricted phenotypes, the p.A382T showed a marked clinical heterogeneity regarding age of onset, survival and association with cognitive impairment. Investigations in parents, when possible, showed that the variants were inherited from healthy carriers and never occurred de novo. CONCLUSIONS: In our cohort, TARDBP variants have a relevant frequency in Italian ALS patients and they are significantly associated with cognitive impairment. Clinical presentation is heterogeneous. Consistent genotype-phenotype correlations are limited to some mutations. A marked phenotypic variability characterizes the p.A382T variant, suggesting a multifactorial/oligogenic pathogenic mechanism.

Differential effects of mutations of POPDC proteins on heteromeric interaction and membrane trafficking.

The Popeye domain containing (POPDC) genes encode sarcolemma-localized cAMP effector proteins. Mutations in blood vessel epicardial substance (BVES) also known as POPDC1 and POPDC2 have been associated with limb-girdle muscular dystrophy and cardiac arrhythmia. Muscle biopsies of affected patients display impaired membrane trafficking of both POPDC isoforms. Biopsy material of patients carrying mutations in BVES were immunostained with POPDC antibodies. The interaction of POPDC proteins was investigated by co-precipitation, proximity ligation, bioluminescence resonance energy transfer and bimolecular fluorescence complementation. Site-directed mutagenesis was utilised to map the domains involved in protein-protein interaction. Patients carrying a novel homozygous variant, BVES (c.547G > T, p.V183F) displayed only a skeletal muscle pathology and a mild impairment of membrane trafficking of both POPDC isoforms. In contrast, variants such as BVES p.Q153X or POPDC2 p.W188X were associated with a greater impairment of membrane trafficking. Co-transfection analysis in HEK293 cells revealed that POPDC proteins interact with each other through a helix-helix interface located at the C-terminus of the Popeye domain. Site-directed mutagenesis of an array of ultra-conserved hydrophobic residues demonstrated that some of them are required for membrane trafficking of the POPDC1-POPDC2 complex. Mutations in POPDC proteins that cause an impairment in membrane localization affect POPDC complex formation while mutations which leave protein-protein interaction intact likely affect some other essential function of POPDC proteins.

Analysis of STMN2 CA repeats in italian ALS patients shows no association.

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease caused by a complex interaction of genetic and environmental factors. Recently, a polymorphic intronic CA repeat in STMN2 gene has been proposed as risk factor for ALS. The presence of long/long CA genotype, especially if one allele had 24 CA, was reported to be significantly associated with the disease in a cohort of sporadic ALS patients. We tested an Italian cohort of 366 ALS patients and 353 healthy controls and we found no association between CA length and ALS risk.

Pupillometric findings in ATTRv patients and carriers: results from a single-centre experience.

INTRODUCTION: Hereditary transthyretin amyloidosis (ATTRv) is a treatable multisystemic disease with great phenotypic heterogeneity. Among extra-neurological features, pupillary abnormalities have been reported, either related to amyloid deposition in the eye or to a progressive autonomic neuropathy. OBJECTIVE: To evaluate the role of automated pupillometry, a non-invasive and rapid test able to provide objective and reproducible data on pupil size and reactivity, as a marker of disease severity in late-onset ATTRv patients. PATIENTS AND METHODS: We performed automated pupillometry on a cohort of ATTRv patients and pre-symptomatic TTR mutation carriers and compared results to healthy controls. An exhaustive clinical and instrumental evaluation was performed on all enrolled subjects. RESULTS: A statistically significant difference in most pupillometry parameters was found in ATTRv patients as compared to both carriers and healthy controls. Moreover, in ATTRv patients, we found a significant correlation between many pupillometry findings and disease duration, as well as widely accepted clinical scales and investigations (NIS, Sudoscan from feet, and Norfolk QoL-DN questionnaire). CONCLUSIONS: We suggest pupillometry may play a role as a reliable and non-invasive biomarker to evaluate ATTRv disease severity and monitor its progression.

Nerve Conduction Studies of Dorsal Sural Nerve: Normative Data and Its Potential Application in ATTRv Pre-Symptomatic Subjects.

The objective of the study is to provide age-related normative values for dorsal sural nerve (DSN) and to analyse its application during follow-up of hereditary transthyretin amyloidosis (ATTRv) pre-symptomatic subjects. We consecutively recruited ATTRv pre-symptomatic carriers in which clinical examination, cardiological evaluation, and nerve conduction studies of the sural nerve and DSN were performed. To provide normative data of DSN, neurophysiologic parameters from healthy controls referred to our service were entered into linear regression analyses to check the relative influence of age and height. A correction grid was then derived. We collected 231 healthy subjects: the mean DSN sensory nerve action potential (SNAP) amplitude was 9.99 ± 5.48 µV; the mean conduction velocity was 49.01 ± 5.31 m/s. Significant correlations were found between age and height with DSN SNAP amplitude. Fifteen ATTRv pre-symptomatic carriers were examined. Sural nerve NCS were normal in 12/15 and revealed low/borderline values in three subjects. Considering our correction grid, we found an abnormal DNS amplitude in 9/15 subjects and low/borderline values in 2/15. In ATTRv, early detection of peripheral nerve damage is crucial to start a disease-modifying treatment. DSN may be easily and reliably included in the routine neurophysiological follow-up of ATTRv pre-symptomatic subjects.

Generation of an induced pluripotent stem cell line (UCSCi002-A) from a patient with a variant in TARDBP gene associated with familial amyotrophic lateral sclerosis and frontotemporal dementia.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that selectively affects motor neurons. In 20% of cases, ALS appears in comorbidity with frontotemporal dementia (FTD). We generated patient-derived-induced Pluripotent Stem Cells (iPSCs), from an ALS/FTD patient. The patient had a familial form of the disease and a missense variant in TARDBP gene. We used an established protocol based on Sendai virus to reprogram fibroblasts. We confirmed the stemness and the pluripotency of the iPSC clones, thus generating embryoid bodies. We believe that the iPSC line carrying a TARDBP mutation could be a valuable tool to investigate TDP-43 proteinopathy linked to ALS.

Characterization of the p.L145F and p.S135N Mutations in SOD1: Impact on the Metabolism of Fibroblasts Derived from Amyotrophic Lateral Sclerosis Patients.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the loss of the upper and lower motor neurons (MNs). About 10% of patients have a family history (familial, fALS); however, most patients seem to develop the sporadic form of the disease (sALS). SOD1 (Cu/Zn superoxide dismutase-1) is the first studied gene among the ones related to ALS. Mutant SOD1 can adopt multiple misfolded conformation, lose the correct coordination of metal binding, decrease structural stability, and form aggregates. For all these reasons, it is complicated to characterize the conformational alterations of the ALS-associated mutant SOD1, and how they relate to toxicity. In this work, we performed a multilayered study on fibroblasts derived from two ALS patients, namely SOD1L145F and SOD1S135N, carrying the p.L145F and the p.S135N missense variants, respectively. The patients showed diverse symptoms and disease progression in accordance with our bioinformatic analysis, which predicted the different effects of the two mutations in terms of protein structure. Interestingly, both mutations had an effect on the fibroblast energy metabolisms. However, while the SOD1L145F fibroblasts still relied more on oxidative phosphorylation, the SOD1S135N fibroblasts showed a metabolic shift toward glycolysis. Our study suggests that SOD1 mutations might lead to alterations in the energy metabolism.