High Frequency of Cognitive and Behavioral Impairment in Amyotrophic Lateral Sclerosis Patients with SOD1 Pathogenic Variants.

OBJECTIVE: While the cognitive-behavioral characteristics of amyotrophic lateral sclerosis (ALS) patients carrying C9orf72 pathological repeat expansion have been extensively studied, our understanding of those carrying SOD1 variants is mostly based on case reports. The aim of this paper is to extensively explore the cognitive-behavioral characteristics of a cohort of ALS patients carrying pathogenetic variants of SOD1 gene, comparing them to patients without pathogenetic variants of 46 ALS-related genes (wild-type [WT]-ALS) and healthy controls. METHODS: All ALS patients seen at the Turin ALS expert center in the 2009-2021 period who underwent both cognitive/behavioral and extensive genetic testing were eligible to be included in the study. Only patients with SOD1 pathogenetic variants (n = 28) (SOD1-ALS) and WT-ALS (n = 829) were enrolled in the study. A series of 129 controls was also included. RESULTS: Among the 28 SOD1-ALS patients, 16 (57.1%) had normal cognitive function, 5 (17.9%) isolated cognitive impairment (ALSci) (17.9%), 6 (21.4%) isolated behavioral impairment (ALSbi), 1 (3.6%) cognitive and behavioral impairment (ALScbi), and no one ALS-FTD. SOD1-ALS performed worse than controls in all explored domains, in particular Social Cognition and Language domains. SOD1-ALS patients had similar scores in all tests compared to WT-ALS, except the Story-based Empathy Task (SET), where they performed worse. INTERPRETATION: Cognitive-behavioral impairment is much more common in SOD1 patients than previously assumed. SOD1-ALS are characterized by a more frequent impairment of Social Cognition and, less markedly, of Language domains. These findings have relevant implication both in the clinical and in the research setting, also considering recently approved treatment for SOD1-ALS. ANN NEUROL 2024.

Sex Differences in Amyotrophic Lateral Sclerosis Survival and Progression: A Multidimensional Analysis.

OBJECTIVE: To investigate sex-related differences in amyotrophic lateral sclerosis (ALS) prognosis and their contributing factors. METHODS: Our primary cohort was the Piemonte and Aosta Register for ALS (PARALS); the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) and the Answer ALS databases were used for validation. Survival analyses were conducted accounting for age and onset site. The roles of forced vital capacity and weight decline were explored through a causal mediation analysis. Survival and disease progression rates were also evaluated after propensity score matching. RESULTS: The PARALS cohort included 1,890 individuals (44.8% women). Men showed shorter survival when stratified by onset site (spinal onset HR 1.20, 95% CI 1.00-1.44, p = 0.0439; bulbar onset HR 1.36, 95% CI 1.09-1.70, p = 0.006917), although women had a steeper functional decline (+0.10 ALSFRS-R points/month, 95% CI 0.07-0.15, p < 0.00001) regardless of onset site. Instead, men showed worse respiratory decline (-4.2 forced vital capacity%/month, 95% CI -6.3 to -2.2, p < 0.0001) and faster weight loss (-0.15 kg/month, 95% CI -0.25 to -0.05, p = 0.0030). Causal mediation analysis showed that respiratory function and weight loss were pivotal in sex-related survival differences. Analysis of patients from PRO-ACT (n = 1,394, 40.9% women) and Answer ALS (n = 849, 37.2% women) confirmed these trends. INTERPRETATION: The shorter survival in men is linked to worse respiratory function and weight loss rather than a faster disease progression. These findings emphasize the importance of considering sex-specific factors in understanding ALS pathophysiology and designing tailored therapeutic strategies. ANN NEUROL 2024.

Calculated Maximal Volume Ventilation (cMVV) as a Marker of Early Respiratory Failure in Amyotrophic Lateral Sclerosis (ALS).

Respiratory failure assessment is among the most debatable research topics in amyotrophic lateral sclerosis (ALS) clinical research due to the wide heterogeneity of its presentation. Among the different pulmonary function tests (PFTs), maximal voluntary ventilation (MVV) has shown potential utility as a diagnostic and monitoring marker, able to capture early respiratory modification in neuromuscular disorders. In the present study, we explored calculated MVV (cMVV) as a prognostic biomarker in a center-based, retrospective ALS population belonging to the Piemonte and Valle d'Aosta registry for ALS (PARALS). A Spearman's correlation analysis with clinical data and PFTs showed a good correlation of cMVV with forced vital capacity (FVC) and a moderate correlation with some other features such as bulbar involvement, ALSFRS-R total score, blood oxygen (pO2), carbonate (HCO3-), and base excess (BE), measured with arterial blood gas analysis. Both the Cox proportional hazard models for survival and the time to non-invasive ventilation (NIV) measurement highlighted that cMVV at diagnosis (considering cMVV(40) ≥ 80) is able to stratify patients across different risk levels for death/tracheostomy and NIV indication, especially considering patients with FVC% ≥ 80. In conclusion, cMVV is a useful marker of early respiratory failure in ALS, and is easily derivable from standard PFTs, especially in asymptomatic ALS patients with normal FVC measures.

Cognitive and Behavioral Features of Patients With Amyotrophic Lateral Sclerosis Who Are Carriers of the TARDBP Pathogenic Variant.

BACKGROUND AND OBJECTIVES: TARDBP patients are considered particularly prone to cognitive involvement, but no systematic studies of cognitive impairment in TARDBP patients are available. The aim of this article was to depict in depth the cognitive-behavioral characteristics of a cohort of patients with amyotrophic lateral sclerosis (ALS) carrying TARDBP pathogenetic variants followed by an ALS referral center. METHODS: We enrolled all patients with ALS seen at the Turin ALS expert center in the 2009-2021 period who underwent extensive genetic testing and a neuropsychological battery encompassing executive function, verbal memory, language, visual memory, visuoconstructive abilities, attention/working memory, psychomotor speed, nonverbal intelligence, cognitive flexibility, social cognition, and behavior. Tests were compared with the Mann-Whitney U test on age-corrected, sex-corrected, and education-corrected scores. Cognition was classified as normal (ALS-CN); isolated cognitive impairment (ALSci), that is, evidence of executive and/or language dysfunction; isolated behavioral impairment (ALSbi), that is, identification of apathy; cognitive and behavioral impairment (ALScbi), that is, evidence meeting the criteria for both ALSci and ALSbi; and frontotemporal dementia (ALS-FTD). RESULTS: This study includes 33 patients with TARDBP pathogenetic variants (TARDBP-ALS) (median age 61 years [interquartile range (IQR) 53-67], 8 female [24.2%]) and 928 patients with ALS not carrying the pathogenic variant (WT-ALS) (median age 67 years [IQR 59-74], 386 female [41.6%]). TARDBP-ALS cases were also compared with 129 matched controls (median age 66 years [IQR 57.5-71.5], 55 female [42.6%]). TARDBP-ALS and WT-ALS patients were cognitively classified as ALS-CN (54% vs 58.8%, respectively), ALSci (21.2% vs 18.3%), ALSci (9.1% vs 9.5%), ALScbi (6.1% vs 6.0%), and ALS-FTD (9.1 vs 6.7%), with no significant difference (p = 0.623). Compared with controls, TARDBP-ALS had a worse performance in executive functions, visual memory, visuoconstructive abilities, verbal fluency, and the apathy behavioral component of FrSBe. The scores of performed tests, including all Edinburgh Cognitive and Behavioral ALS Screen subdomains, were similar in TARDBP-ALS and WT-ALS. DISCUSSION: TARDBP-ALS patients were significantly more impaired than controls in most examined domains but do not show any specific pattern of cognitive impairment compared with WT-ALS. Our findings are relevant both clinically, considering the effect of cognitive impairment on patients' decision-making and caregivers' burden, and in designing clinical trials for the treatment of patients carrying TARDBP pathogenetic variants.

Giving Breath to Motor Neurons: Noninvasive Mechanical Ventilation Slows Disease Progression in Amyotrophic Lateral Sclerosis.

OBJECTIVE: Noninvasive mechanical ventilation (NIMV) improves amyotrophic lateral sclerosis (ALS) quality of life and survival. However, data about its effect on disease progression are still lacking. Here, we test whether NIMV use changed the rate of functional decline among ALS patients. METHODS: In this retrospective observational study, we included 448 ALS patients followed up at the ALS Center in Turin, Italy, who underwent NIMV during the disease course. The primary outcome was the change in functional decline after NIMV initiation adjusting for covariates. Functional decline was based on the nonrespiratory items of the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R). RESULTS: NIMV initiation resulted in a slower functional decline (mean improvement = 0.16 points per month, 95% confidence interval = 0.12-0.19, p < 0.001), with consistent effects observed across various demographic factors, including sex, age at diagnosis, and disease duration before NIMV initiation. This finding was replicated using the PRO-ACT (Pooled Resource Open-Access ALS Clinical Trials) dataset. The favorable impact of NIMV on ALSFRS-R progression was evident independently of disease stages. Notably, NIMV benefits were not dose-dependent but were particularly prominent for nighttime respiratory support. INTERPRETATION: NIMV significantly influences the rate of motor progression in ALS, and this effect is not determined by the nonlinearity of ALSFRS-R trajectory. The functional decline slowed following NIMV initiation, independently of the site of disease onset or disease severity at the time of NIMV initiation. Our findings underscore the importance of timely NIMV initiation for all ALS patients and highlight the need to consider NIMV-induced slowing of disease progression when evaluating clinical trial outcomes. ANN NEUROL 2024;95:817-822.

High serum uric acid levels are protective against cognitive impairment in amyotrophic lateral sclerosis.

BACKGROUND: Uric acid (UA) has emerged as a factor that can modify cognitive function both in the general population and in people with neurodegenerative disorders. Since very few data are available concerning amyotrophic lateral sclerosis (ALS), we explored the correlation of UA levels and cognitive impairment in a large cohort of ALS patients. METHODS: We enrolled ALS patients consecutively seen at the Turin ALS expert center in the 2007-2018 period who underwent both cognitive/behavioral and UA evaluation at diagnosis. Patients were classified in 5 categories: normal cognition (ALS-CN), isolated cognitive impairment (ALSci), isolated behavioural impairment (ALSbi), cognitive and behavioural impairment (ALScbi), frontotemporal dementia (ALS-FTD). For this study, ALSci, ALSbi and ALScbi were merged as ALS with intermediate cognitive impairment (ALS-INT). RESULTS: Out of the 841 ALS patients, 422 had ALS-CN, 271 ALS-INT and 148 ALS-FTD. The mean values of UA were significantly different among the cognitive subgroups of patients, with the lowest values in the ALS-FTD (ALS-CN, 288.5 ± 78.0 (µmol/L; ALS-INT, 289.7 ± 75.5 µmol/L; ALS-FTD, 271.8 ± 74.9 µmol/L; p = 0.046). The frequency of ALS-FTD was significantly higher in the 1st tertile of UA. Lower UA levels were independently associated with FTD (OR 1.32, 95% c.i. 1.01-1.43; p = 0.038) in binary logistic regression. CONCLUSIONS: We found that in ALS lower UA serum levels are correlated with reduced frequency of co-morbid FTD. Patients with intermediate cognitive impairment showed UA levels similar to ALS-CN but higher than ALS-FTD, implying that higher UA levels can prevent or delay cognitive function deterioration.

Predictors for progression in amyotrophic lateral sclerosis associated to SOD1 mutation: insight from two population-based registries.

BACKGROUND: Uncovering distinct features and trajectories of amyotrophic lateral sclerosis (ALS) associated with SOD1 mutations (SOD1-ALS) can provide valuable insights for patient' counseling and stratification for trials, and interventions timing. Our study aims to pinpoint distinct clinical characteristics of SOD1-ALS by delving into genotype-phenotype correlations and factors that potentially impact disease progression. METHODS: This is a retrospective observational study of a SOD1-ALS cohort from two Italian registers situated in the regions of Emilia-Romagna, Piedmont and Valle d'Aosta. RESULTS: Out of 2204 genotyped ALS patients, 2.5% carried SOD1 mutations, with a M:F ratio of 0.83. SOD1-ALS patients were younger, and more frequently reported a family history of ALS and/or FTD. SOD1-ALS had a longer survival compared to patients without ALS-associated gene mutations. However, here was considerable variability in survival across distinct SOD1 mutations, with an average survival of less than a year for the L39V, G42S, G73S, D91N mutations. Among SOD1-ALS, multivariate analysis showed that, alongside established clinical prognostic factors such as advanced age at onset and high progression rate at diagnosis, mutations located in exon 2 or within highly conserved gene positions predicted worse survival. Conversely, among comorbidities, cancer history was independently associated with longer survival. INTERPRETATION: Within the context of an overall slower disease, SOD1-ALS exhibits some degree of heterogeneity linked to the considerable genetic diversity arising from the multitude of potential mutations sites and specific clinical prognostic factors, including cancer history. Revealing the factors that modulate the phenotypic heterogeneity of SOD1-ALS could prove advantageous in improving the efficacy of upcoming therapeutic approaches.

The role of peripheral immunity in ALS: a population-based study.

BACKGROUND: Systemic inflammation has been proposed as a relevant mechanism in amyotrophic lateral sclerosis (ALS). Still, comprehensive data on ALS patients' innate and adaptive immune responses and their effect on the clinical phenotype are lacking. Here, we investigate systemic immunity in a population-based ALS cohort using readily available hematological indexes. METHODS: We collected clinical data and the complete blood count (CBC) at diagnosis in ALS patients from the Piemonte and Valle d'Aosta Register for ALS (PARALS) from 2007 to 2019. Leukocytes populations, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic-immune-inflammation index (SII), and lymphocyte-to-monocyte ratio (LMR) were derived from CBC. All variables were analyzed for association with clinical features in the entire cohort and then in sex- and age-based subgroups. RESULTS: Neutrophils (P = 0.001) and markers of increased innate immunity (NLR, P = 0.008 and SII, P = 0.006) were associated with a faster disease progression. Similarly, elevated innate immunity correlated with worse pulmonary function and shorter survival. The prognosis in women also correlated with low lymphocytes (P = 0.045) and a decreased LMR (P = 0.013). ALS patients with cognitive impairment exhibited lower monocytes (P = 0.0415). CONCLUSIONS AND RELEVANCE: The dysregulation of the systemic immune system plays a multifaceted role in ALS. More specifically, an elevated innate immune response is associated with faster progression and reduced survival. Conversely, ALS patients with cognitive impairment showed a reduction in monocyte count. Additionally, immune response varied according to sex and age, thus suggesting that involved immune pathways are patient specific. Further studies will help translate those findings into clinical practice or targeted treatments.

Serum chloride as a respiratory failure marker in amyotrophic lateral sclerosis.

Respiratory failure is the most common cause of death in patients with amyotrophic lateral sclerosis (ALS) and occurs with great variability among patients according to different phenotypic features. Early predictors of respiratory failure in ALS are important to start non-invasive ventilation (NIV). Venous serum chloride values correlate with carbonate (HCO3-) blood levels and reflect metabolic compensation of respiratory acidosis. Despite its wide availability and low cost, few data on serum chloride as a prognostic marker exist in ALS literature. In the present study, we evaluated serum chloride values at diagnosis as prognostic biomarkers for overall survival and NIV adaptation in a retrospective center-based cohort of ALS patients. We collected all ALS patients with serum chloride assessment at diagnosis, identified through the Piemonte and Valle d'Aosta Register for ALS, evaluating the correlations among serum chloride, clinical features, and other serum biomarkers. Thereafter, time-to-event analysis was modeled to predict overall survival and NIV start. We found a significant correlation between serum chloride and inflammatory status markers, serum sodium, forced vital capacity (FVC), ALS functional rating scale-revised (ALSFRS-R) item 10 and 11, age at diagnosis, and weight loss. Time-to-event analysis confirmed both in univariate analysis and after multiple confounders' adjustment that serum chloride value at diagnosis significantly influenced survival and time to NIV start. According to our analysis, based on a large ALS cohort, we found that serum chloride analyzed at diagnosis is a low-cost marker of impending respiratory decompensation. In our opinion, it should be added among the serum prognostic biomarkers that are able to stratify patients into different prognostic categories even when performed in the early phases of the disease.

Association of Copresence of Pathogenic Variants Related to Amyotrophic Lateral Sclerosis and Prognosis.

BACKGROUND AND OBJECTIVES: Despite recent advances, it is not clear whether the various genes/genetic variants related to amyotrophic lateral sclerosis (ALS) interact in modifying patients' phenotype. The aim of this study was to determine whether the copresence of genetic variants related to ALS has interactive effects on the course of the disease. METHODS: The study population includes 1,245 patients with ALS identified through the Piemonte Register for ALS between 2007 and 2016 and not carrying superoxide dismutase type 1, TAR DNA binding protein, and fused in sarcoma pathogenic variants. Controls were 766 Italian participants age-matched, sex-matched, and geographically matched to cases. We considered Unc-13 homolog A (UNC13A) (rs12608932), calmodulin binding transcription activator 1 (CAMTA1) (rs2412208), solute carrier family 11 member 2 (SLC11A2) (rs407135), and zinc finger protein 512B (ZNF512B) (rs2275294) variants, as well as ataxin-2 (ATXN2) polyQ intermediate repeats (≥31) and chromosome 9 open reading frame 72 (C9orf72) GGGGCC intronic expansions (≥30). RESULTS: The median survival time of the whole cohort was 2.67 years (interquartile range [IQR] 1.67-5.25). In univariate analysis, only C9orf72 (2.51 years, IQR 1.74-3.82; p = 0.016), ATXN2 (1.82 years, IQR 1.08-2.33; p < 0.001), and UNC13A C/C (2.3 years, IQR 1.3-3.9; p < 0.001) significantly reduced survival. In Cox multivariable analysis, CAMTA1 also emerged to be independently related to survival (hazard ratio 1.13, 95% CI 1.001-1.30, p = 0.048). The copresence of 2 detrimental alleles/expansions was correlated with shorter survival. In particular, the median survival of patients with CAMTA1 G/G+G/T and UNC13A C/C alleles was 1.67 years (1.16-3.08) compared with 2.75 years (1.67-5.26) of the patients not carrying these variants (p < 0.001); the survival of patients with CAMTA1 G/G+G/T alleles and ATXN2 ≥31 intermediate polyQ repeats was 1.75 years (0.84-2.18) (p < 0.001); the survival of patients with ATXN2 ≥31 polyQ repeats and UNC13A C/C allele was 1.33 years (0.84-1.75) (p < 0.001); the survival of patients with C9ORF72 ≥30 and UNC13A C/C allele was 1.66 years (1.41-2.16). Each pair of detrimental alleles/expansions was associated to specific clinical phenotypes. DISCUSSION: We showed that gene variants acting as modifiers of ALS survival or phenotype can act on their own or in unison. Overall, 54% of patients carried at least 1 detrimental common variant or repeat expansion, emphasizing the clinical impact of our findings. In addition, the identification of the interactive effects of modifier genes represents a crucial clue for explaining ALS clinical heterogeneity and should be considered when designing and interpreting clinical trials results.

Amyotrophic lateral sclerosis regional progression intervals change according to time of involvement of different body regions.

BACKGROUND AND PURPOSE: The prediction of disease course is one of the main targets of amyotrophic lateral sclerosis (ALS) research, particularly considering its wide phenotypic heterogeneity. Despite many attempts to classify patients into prognostic categories according to the different spreading patterns at diagnosis, a precise regional progression rate and the time of involvement of each region has yet to be clarified. The aim of our study was to evaluate the functional decline in different body regions according to their time of involvement during disease course. METHODS: In a population-based dataset of ALS patients, we analysed the functional decline in different body regions according to time and order of regional involvement. We calculated the regional progression intervals (RPIs) between initial involvement and severe functional impairment using the ALS Functional Rating Scale revised (ALSFRS-r) subscores for the bulbar, upper limb, lower limb and respiratory/thoracic regions. Time-to-event analyses, adjusted for age, sex, ALSFRS-r pre-slope (ΔALSFRS-R), cognitive status, and mutational status were performed. RESULTS: The duration of RPI differed significantly among ALS phenotypes, with the RPI of the first region involved being significantly longer than the RPIs of regions involved later. Cox proportional hazard models showed that in fact a longer time between disease onset and initial regional involvement was related to a reduced duration of the RPI duration in each different body region (bulbar region: hazard ratio [HR] 1.11, 95% confidence interval [CI] 1.06-1.16, p < 0.001; upper limb region: HR 1.16, 95% CI 1.06-1.28, p = 0.002; lower limb region: HR 1.11, 95% CI 1.03-1.19, p = 0.009; respiratory/thoracic region: HR 1.10, 95% CI 1.06-1.14, p = 0.005). CONCLUSIONS: We found that the progression of functional decline accelerates in regions involved later during disease course. Our findings can be useful in patient management and prognosis prediction.

Integrative genetic analysis illuminates ALS heritability and identifies risk genes.

Amyotrophic lateral sclerosis (ALS) has substantial heritability, in part shared with fronto-temporal dementia (FTD). We show that ALS heritability is enriched in splicing variants and in binding sites of 6 RNA-binding proteins including TDP-43 and FUS. A transcriptome wide association study (TWAS) identified 6 loci associated with ALS, including in NUP50 encoding for the nucleopore basket protein NUP50. Independently, rare variants in NUP50 were associated with ALS risk (P = 3.71.10-03; odds ratio = 3.29; 95%CI, 1.37 to 7.87) in a cohort of 9,390 ALS/FTD patients and 4,594 controls. Cells from one patient carrying a NUP50 frameshift mutation displayed a decreased level of NUP50. Loss of NUP50 leads to death of cultured neurons, and motor defects in Drosophila and zebrafish. Thus, our study identifies alterations in splicing in neurons as critical in ALS and provides genetic evidence linking nuclear pore defects to ALS.

Exposure to electromagnetic fields does not modify neither the age of onset nor the disease progression in ALS patients.

Being exposed to electromagnetic fields has been suggested to increase the risk of developing Amyotrophic Lateral Sclerosis (ALS). Here, we investigated the effect of exposure to electromagnetic fields on ALS onset age and progression rate (ΔALSFRS-r). A large cohort of ALS patients (n = 1098) was geolocalized at the time of their diagnosis. Concomitantly, data on the distribution of power lines and repeater antennas (extremely low frequency electromagnetic fields) during the same period were retrieved. Exposure to each repeater antenna was calculated as the sum of 1/(distance from each antenna)^2. Exposure to power lines was calculated assuming each patient's address as the center of several circles of variable radius (100, 250, 500, 1000, and 2000 m). For each radius, the exposure was calculated as the length of the power lines included in the circle. Finally, patients were divided into low- and high-exposed based on the median of the exposure and compared using the Mann-Whitney test. A regression model (one for each radius) was also performed. Neither the onset age nor the ΔALSFRS-r differed among patients' low- and high-exposed to electromagnetic fields. Similarly, we could not find any significant relationship using the regression models. Our findings suggest that electromagnetic fields do not modify the ALS phenotype or progression.

Factors predicting disease progression in C9ORF72 ALS patients.

OBJECTIVE: To unveil clinical features, comorbidities, disease progression and prognostic factors in a population-based cohort of ALS patients carrying C9ORF72 expansion (C9 + ALS). METHODS: This is a retrospective observational study on ALS patients residing in Emilia Romagna and Piedmont-Valle D'Aosta regions whose data are available through population based registers. We analysed patients who underwent genetic testing, focusing on C9 + ALS subgroup. RESULTS: Among 2204 genotyped patients of the two registers, 150 were C9 + ALS. In comparison with patients without mutation, a higher proportion of family history (12.85 vs 68%, p < 0.001) and frontotemporal dementia (3.93% vs 10.67%, p < 0.001) was detected in C9 + ALS. C9 + ALS presented a faster disease progression as measured by monthly decline in ALS Functional Rating Scale-Revised (1.86 ± 3.30 vs 1.45 ± 2.35, p < 0.01) and in forced vital capacity (5.90 ± 5.24 vs 2.97 ± 3.47, p < 0.01), a shorter diagnostic delay (8.93 ± 6.74 vs 12.68 ± 12.86 months, p < 0.01) and earlier onset (58.91 ± 9.02 vs 65.04 ± 11.55 years, p < 0.01). Consistently, they reached death or tracheostomy earlier than other patients (31 vs 37 months, HR = 1.52, 95% C.I. 1.27-1.82, p < 0.001). With respect to other genotyped patients, C9 + ALS patients did not present a significantly higher prevalence of concomitant diseases. Independent prognostic factors of survival of C9 + ALS included sex, age, progression rate, presence of frontotemporal dementia and thyroid disorders, with the latter being associated with prolonged ALS survival (43 vs 29 months, HR = 0.42, 95% C.I. 0.24-0.74, p = 0.003). CONCLUSION: Even in the context of a more aggressive disease, C9 + ALS had a longer survival in presence of thyroid disorders. This finding may suggest protective pathogenic pathways in C9 + ALS to be explored, looking for therapeutic strategies to slow disease course.

Brain metabolic differences between pure bulbar and pure spinal ALS: a 2-[18F]FDG-PET study.

BACKGROUND: MRI studies reported that ALS patients with bulbar and spinal onset showed focal cortical changes in corresponding regions of the motor homunculus. We evaluated the capability of brain 2-[18F]FDG-PET to disclose the metabolic features characterizing patients with pure bulbar or spinal motor impairment. METHODS: We classified as pure bulbar (PB) patients with bulbar onset and a normal score in the spinal items of the ALSFRS-R, and as pure spinal (PS) patients with spinal onset and a normal score in the bulbar items at the time of PET. Forty healthy controls (HC) were enrolled. We compared PB and PS, and each patient group with HC. Metabolic clusters showing a statistically significant difference between PB and PS were tested to evaluate their accuracy in discriminating the two groups. We performed a leave-one-out cross-validation (LOOCV) over the entire dataset. Four classifiers were considered: support vector machines (SVM), K-nearest neighbours, linear classifier, and decision tree. Then, we used a separate test set, including 10% of patients, with the remaining 90% composing the training set. RESULTS: We included 63 PB, 271 PS, and 40 HC. PB showed a relative hypometabolism compared to PS in bilateral precentral gyrus in the regions of the motor cortex involved in the control of bulbar function. SVM showed the best performance, resulting in the lowest error rate in both LOOCV (4.19%) and test set (9.09 ± 2.02%). CONCLUSIONS: Our data support the concept of the focality of ALS onset and the use of 2-[18F]FDG-PET as a biomarker for precision medicine-oriented clinical trials.

Role of brain 2-[18F]fluoro-2-deoxy-D-glucose-positron-emission tomography as survival predictor in amyotrophic lateral sclerosis.

PURPOSE: The identification of prognostic tools in amyotrophic lateral sclerosis (ALS) would improve the design of clinical trials, the management of patients, and life planning. We aimed to evaluate the accuracy of brain 2-[18F]fluoro-2-deoxy-D-glucose-positron-emission tomography (2-[18F]FDG-PET) as an independent predictor of survival in ALS. METHODS: A prospective cohort study enrolled 418 ALS patients, who underwent brain 2-[18F]FDG-PET at diagnosis and whose survival time was available. We discretized the survival time in a finite number of classes in a data-driven fashion by employing a k-means-like strategy. We identified "hot brain regions" with maximal power in discriminating survival classes, by evaluating the Laplacian scores in a class-aware fashion. We retained the top-m features for each class to train the classification systems (i.e., a support vector machine, SVM), using 10% of the ALS cohort as test set. RESULTS: Data were discretized in three survival profiles: 0-2 years, 2-5 years, and > 5 years. SVM resulted in an error rate < 20% for two out of three classes separately. As for class one, the discriminant clusters included left caudate body and anterior cingulate cortex. The most discriminant regions were bilateral cerebellar pyramid in class two, and right cerebellar dentate nucleus, and left cerebellar nodule in class three. CONCLUSION: Brain 2-[18F]FDG-PET along with artificial intelligence was able to predict with high accuracy the survival time range in our ALS cohort. Healthcare professionals can benefit from this prognostic tool for planning patients' management and follow-up. 2-[18F]FDG-PET represents a promising biomarker for individual patients' stratification in clinical trials. The lack of a multicentre external validation of the model warrants further studies to evaluate its generalization capability.

Clinical and Metabolic Signature of UNC13A rs12608932 Variant in Amyotrophic Lateral Sclerosis.

Background and Objectives: To characterize the clinical and cognitive behavioral phenotype and brain 18F-2-fluoro-2-deoxy-d-glucose-PET (18F-FDG-PET) metabolism of patients with amyotrophic lateral sclerosis (ALS) carrying the rs12608932 variant of the UNC13A gene. Methods: The study population included 1,409 patients with ALS without C9orf72, SOD1, TARDBP, and FUS mutations identified through a prospective epidemiologic ALS register. Control participants included 1,012 geographically matched, age-matched, and sex-matched participants. Clinical and cognitive differences between patients carrying the C/C rs12608932 genotype and those carrying the A/A + A/C genotype were assessed. A subset of patients underwent 18F-FDG-PET. Results: The C/C genotype was associated with an increased risk of ALS (odds ratio: 1.54, 95% confidence interval 1.18-2.01, p = 0.001). Patients with the C/C genotype were older, had more frequent bulbar onset, and manifested a higher rate of weight loss. In addition, they showed significantly reduced performance in the letter fluency test, fluency domain of Edinburgh Cognitive and Behavioural ALS Screen (ECAS) and story-based empathy task (reflecting social cognition). Patients with the C/C genotype had a shorter survival (median survival time, C/C 2.25 years, interquartile range [IQR] 1.33-3.92; A/A + C/C: 2.90 years, IQR 1.74-5.41; p = 0.0001). In Cox multivariable analysis, C/C genotype resulted to be an independent prognostic factor. Finally, patients with a C/C genotype had a specific pattern of hypometabolism on brain 18F-FDG-PET extending to frontal and precentral areas of the right hemisphere. Discussion: C/C rs12608932 genotype of UNC13A is associated with a specific motor and cognitive/behavioral phenotype, which reflects on 18F-FDG-PET findings. Our observations highlight the importance of adding the rs12608932 variant in UNC13A to the ALS genetic panel to refine the individual prognostic prediction and reduce heterogeneity in clinical trials.

Phenotype Analysis of Fused in Sarcoma Mutations in Amyotrophic Lateral Sclerosis.

Background and Objectives: Pathogenic variations in fused in sarcoma (FUS) are among the most common genetic causes of amyotrophic lateral sclerosis (ALS) worldwide. They are supposedly characterized by a homogeneous pure motor phenotype with early-onset and short disease duration. However, a few FUS-mutated cases with a very late disease onset and slow progression have been reported. To analyze genotype-phenotype correlations and identify the prognostic factors in FUS-ALS cases. Methods: We identified and cross-sectionally analyzed 22 FUS-ALS patient histories from a single-center cohort of 2,615 genetically tested patients and reviewed 289 previously published FUS-ALS cases. Survival analysis was performed by Kaplan-Meier survival curves, followed by the log-rank test and multivariate Cox analysis. Results: Survival of FUS-ALS is age-dependent: In our cohort, early-onset cases had a rapid disease progression and short survival (p = 0.000003) while the outcome of FUS-mutated patients with mid-to-late onset did not differ from non-FUS-ALS patients (p = 0.437). Meta-analysis of literature data confirmed this trend (p = 0.00003). This survival pattern is not observed in other ALS-related genes in our series. We clustered FUS-ALS patients in 3 phenotypes: (1) axial ALS, with upper cervical and dropped-head onset in mid-to-late adulthood; (2) benign ALS, usually with a late-onset and slow disease progression; and (3) juvenile ALS, often with bulbar onset and preceded by learning disability or mild mental retardation. Those phenotypes arise from different mutations. Discussion: We observed specific genotype-phenotype correlations of FUS-ALS and identified age at onset as the most critical prognostic factor. Our results demonstrated that FUS mutations underlie a specific subtype of ALS and enable a careful stratification of newly diagnosed FUS-ALS cases for clinical course and potential therapeutic windows. This will be crucial in the light of incoming gene-specific therapy.