BACKGROUND:There is evidence that some Hereditary Spastic Paraplegia (HSP) genes are linked to Amyotrophic Lateral Sclerosis (ALS). In particular, KIF5A and SPG11 genes, which cause two different forms of HSP, are also associated with adult-onset and Juvenile ALS, respectively. OBJECTIVES:To study the frequencies of pathogenetic and likely pathogenetic variants in HSP genes in ALS patients and to determine whether they act as predisposing factors. METHODS:We analysed 72 HSP-associated genes in 1024 ALS and 44 Primary Lateral Sclerosis patients and applied customized ACMG criteria to identify pathogenic and likely pathogenic variants. Based on the frequency of identified variants, six genes, including SPG7, SPG11 and the four genes encoding the subunits of the AP4 adaptor protein, were selected for analysis in an additional cohort of 481 ALS patients. Overall results on 1549 patients were compared with 1138 controls. RESULTS:The frequency of variants in SPG7 gene was 0.45% (7/1549) in patients vs 0.18% (2/1138) in controls (p = 0.19), in SPG11 was 0.77% (12/1549) in cases and 0.26% (3/1138) in controls (p = 0.06), in AP4 genes was 0.64% (10/1549) in patients and 0.26% (3/1138) in controls (p = 0.13). The total number of variants detected across SPG7, SPG11 and AP4 genes was statistically different between patients and controls (1.87% vs 0.7%; p = 0.006). CONCLUSIONS:We found a significant enrichment of variants in a set of HSP genes, including SPG7, SPG11 and AP4 genes, in a large cohort of ALS patients, suggesting that they may act as predisposing factors for ALS.

Objectives: Variants in Cyclin F (CCNF) have been associated to amyotrophic lateral sclerosis (ALS) and/or frontotemporal dementia (FTD) in a group of cases. The objectives of this study were to determine the contribution of CCNF in a large cohort of Italian ALS patients, to look for genotype-phenotype correlation of the mutations and to evaluate the CCNF-associated clinical features. Methods: We applied next-generation sequencing technologies on 971 unrelated Italian ALS patients and we filtered results to look for variants in CCNF gene. Results: We identified 13 rare missense variants in 16 index cases (2 familial and 14 sporadic), with a cumulative mutational frequency of 1.6%. The most prevalent variant was p.Phe197Leu, found in three patients. The clinical presentation was heterogeneous, with a classic phenotype in eight patients, upper motor neuron dominant (UMN-D) phenotype in four patients, and flail arm in four patients. Clinical evaluation for cognitive impairment was performed in 13 patients using the Edinburgh Cognitive and Behavioural ALS Screen (ECAS) test, demonstrating that almost half of the patients (n = 6) had variable degrees of frontal dysfunction. Discussion: In our cohort, we observed CCNF variants in 1.6% of patients (16/971), a percentage similar to that found in other series. Clinical presentation is heterogeneous, but CCNF variants are significantly associated to cognitive impairment. Conclusions: Our study expands the CCNF genetic variant spectrum in a large cohort of Italian ALS patients. Further studies are needed to assess genotype-phenotype associations of CCNF variants and to specify the role of each variant, which are quite common, especially in sALS patients.

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.

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. 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. 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

Hereditary transthyretin amyloidosis (ATTRv) is a genetic, autosomal dominant, severe disease characterized by progressive sensory-motor polyneuropathy, cardiomyopathy, dysautonomia, renal and eyes involvement, provoked by the deposition of the mutated and unstable transthyretin protein. In past decades, liver transplant, avoiding the synthesis of the pathologic protein, has been a good, even if not resolutive, treatment. In this report we describe two siblings affected with ATTRv, who developed first symptoms of disease at a young age and underwent a liver transplant with prompt resolution of clinical manifestations. After several years, central nervous system and eyes symptoms relapsed despite treatment, considering that the synthesis of mutated protein continues in choroid plexus, a locum where current therapies are unable to act. In our opinion, these cases represent a long-term prognostic model for the novel gene-silencers approved for ATTRv, because they share a similar therapeutic effect with liver transplant: the block of mutated protein synthesis limited only in the main transthyretin (TTR) production organ is able to prevent the progression of disease only for some years, but not to avoid long-term clinical worsening due to extra-hepatic production of TTR. Novel future therapeutic strategies are demanded to guarantee a better long-term stabilization of symptomatology.

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.

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.

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.

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.

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.

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.

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.

Chronic motor neuropathy/neuronopathy (CMNs) encompass a group of rare diseases characterized by muscle weakness mainly affecting distal muscles of the limbs. Muscle magnetic resonance imaging (MRI) can be a useful tool for the diagnostic workup but has not been explored systematically in these patients. This is a retrospective study collecting clinical, genetic and imaging data. Muscle MRI included T1-weighted and Short Tau Inversion Recovery (STIR) sequences. Fat replacement was quantified using the Mercuri score. Identification of patterns was performed using hierarchical clustering. We included 76 patients with a clinical and electrophysiological diagnosis of CMN. A pathogenic gene variant was identified in 29 subjects, a VUS was identified in 15 and 32 subjects remained without molecular diagnosis. We collected 25 whole-body and 51 lower limb (LL) MRIs. All patients but one had pathological findings. We identified features common to all patients regardless of the genetic diagnosis. Muscle fat replacement was predominant in the LL distal muscles (75/76 cases), but also affected the thigh in 59, the pelvis in 18 and the trunk/upper limb muscles in seven. The posterior compartment of the leg, including soleus and gastrocnemius, was the most affected (71/76) followed by the peronei (63/76). Asymmetric involvement was found in 19 patients. A distal to proximal gradient of fat replacement was observed in 39 patients (52%). Texture analysis showed a reticular pattern or "muscle islets" in 63 patients (83%). Hyperintensities on STIR were observed in 49/59 and were predominantly located in the distal LL muscles. A distal to proximal gradient in STIR was observed in 25 subjects. Besides features common to all individuals, we identified a pattern of muscle fat replacement characteristic of BICD2 and HSPB1 patients. We did not identify a correlation between fat content and age, disease duration or motor functionality. Muscle MRI of CMN patients reveals common features that could be helpful for the diagnosis of patients. We have observed a pattern of MRI involvement characteristic of patients with mutations in specific genes. There was no correlation between fat content and functional status or time of disease progression. Chronic motor neuropathy/neuronopathy (CMNs) encompass a group of rare diseases characterized by muscle weakness mainly affecting distal muscles of the limbs. Muscle magnetic resonance imaging (MRI) can be a useful tool for the diagnostic workup but has not been explored systematically in these patients. This is a retrospective study collecting clinical, genetic and imaging data. Muscle MRI included T1-weighted and Short Tau Inversion Recovery (STIR) sequences. Fat replacement was quantified using the Mercuri score. Identification of patterns was performed using hierarchical clustering. We included 76 patients with a clinical and electrophysiological diagnosis of CMN. A pathogenic gene variant was identified in 29 subjects, a VUS was identified in 15 and 32 subjects remained without molecular diagnosis. We collected 25 whole-body and 51 lower limb (LL) MRIs. All patients but one had pathological findings. We identified features common to all patients regardless of the genetic diagnosis. Muscle fat replacement was predominant in the LL distal muscles (75/76 cases), but also affected the thigh in 59, the pelvis in 18 and the trunk/upper limb muscles in seven. The posterior compartment of the leg, including soleus and gastrocnemius, was the most affected (71/76) followed by the peronei (63/76). Asymmetric involvement was found in 19 patients. A distal to proximal gradient of fat replacement was observed in 39 patients (52%). Texture analysis showed a reticular pattern or "muscle islets" in 63 patients (83%). Hyperintensities on STIR were observed in 49/59 and were predominantly located in the distal LL muscles. A distal to proximal gradient in STIR was observed in 25 subjects. Besides features common to all individuals, we identified a pattern of muscle fat replacement characteristic of BICD2 and HSPB1 patients. We did not identify a correlation between fat content and age, disease duration or motor functionality. Muscle MRI of CMN patients reveals common features that could be helpful for the diagnosis of patients. We have observed a pattern of MRI involvement characteristic of patients with mutations in specific genes. There was no correlation between fat content and functional status or time of disease progression.

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.

Hereditary amyloidosis associated with mutations in the transthyretin gene (hATTR) is a progressive devastating disease, with a fatal outcome occurring within 10years after onset. In recent years, TTR gene silencing therapy appeared as a promising therapeutic strategy, showing evidence that disease progression can be slowed and perhaps reversed. We report here 18 subjects affected by hATTR amyloidosis treated with patisiran, a small interfering RNA acting as TTR silencer, and evaluated with a PND score, the NIS and NIS-LL scale, and a Norfolk QOL-DN questionnaire at baseline and then every 6 months. A global clinical stabilizationwas observed for the majority of the patients, with mild-moderate improvements in some cases, even in advanced disease stage (PND score > 2). Analysis of NIS, NIS-LL and Norfolk QOL-DN results, and PND score variation suggest the possible presence of a 6-month latency period prior to benefit of treatment.

In the last few years, NEK1 has been identified as a new gene related to amyotrophic lateral sclerosis (ALS). Loss-of-function variants have been mostly described, although several missense variants exist, which pathogenic relevance remains to be established. We attempted to determine the contribution of NEK1 gene in an Italian cohort of 531 sporadic and familial amyotrophic lateral sclerosis (ALS) patients applying massive parallel sequencing technologies. We filtered results of NEK1 gene and identified 20 NEK1 rare variants (MAF < 0.01) in 22 patients. In particular, we found two novel frameshift variants (p.Glu929Asnfs*12 and p.Val1030Ilefs*23), 18 missense variants, including the p.Arg261His in three patients, and a novel variant in the start codon, the p.Met1?, which most likely impairs translation initiation. To clarify the role of NEK1 missense variants we investigated NEK1 expression in primary fibroblast cultures. We obtained skin biopsies from four patients with NEK1 variants and we assessed NEK1 expression by western blot and immunofluorescence. We detected a decrease in NEK1 expression in fibroblasts from patients with NEK1 variants, suggesting that missense variants in NEK1 gene may have a pathogenic role. Moreover, we observed additional variants in ALS related genes in seven patients with NEK1 variants (32%), further supporting an oligogenic ALS model.