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.

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.

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.

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.

Causal associations of genetic factors with clinical progression in amyotrophic lateral sclerosis.

BACKGROUND AND OBJECTIVE: Recent advances in the genetic causes of ALS reveals that about 10% of ALS patients have a genetic origin and that more than 30 genes are likely to contribute to this disease. However, four genes are more frequently associated with ALS: C9ORF72, TARDBP, SOD1, and FUS. The relationship between genetic factors and ALS progression rate is not clear. In this study, we carried out a causal analysis of ALS disease with a genetics perspective in order to assess the contribution of the four mentioned genes to the progression rate of ALS. METHODS: In this work, we applied a novel causal learning model to the CRESLA dataset which is a longitudinal clinical dataset of ALS patients including genetic information of such patients. This study aims to discover the relationship between four mentioned genes and ALS progression rate from a causation perspective using machine learning and probabilistic methods. RESULTS: The results indicate a meaningful association between genetic factors and ALS progression rate with causality viewpoint. Our findings revealed that causal relationships between ALSFRS-R items associated with bulbar regions have the strongest association with genetic factors, especially C9ORF72; and other three genes have the greatest contribution to the respiratory ALSFRS-R items with a causation point of view. CONCLUSIONS: The findings revealed that genetic factors have a significant causal effect on the rate of ALS progression. Since C9ORF72 patients have higher proportion compared to those carrying other three gene mutations in the CRESLA cohort, we need a large multi-centric study to better analyze SOD1, TARDBP and FUS contribution to the ALS clinical progression. We conclude that causal associations between ALSFRS-R clinical factors is a suitable predictor for designing a prognostic model of ALS.

A novel splice site FUS mutation in a familial ALS case: effects on protein expression.

Objective: To investigate the impact of a novel heterozygous FUS mutation in the acceptor splice site of intron 14 (c.1542 - 1 g > t) on protein expression in Peripheral Blood Mononuclear Cells (PBMC) from a familial ALS patient. Methods: PBMC were isolated for mRNA analysis (cDNA synthesis, sequencing and one-step RT-PCR), Western Immunoblot (WI), and Immunofluorescence (IF). Results: cDNA analysis revealed the skipping of exon 15 and a premature stop codon at c.228. RT-PCR showed reduced FUS mRNA by more than half compared to a healthy control (HC) and an ALS patient without genetic mutations (wtALS). In WI FUS band intensity in the proband was 30-50% compared to HC and wtALS. An antibody expected to detect only the wild-type protein did not reveal any reduction of FUS band intensity compared to the other antibodies. IF showed no difference among HC, wtALS, and the proband. Discussion: The reduction of FUS mRNA and protein in PBMC suggests the absence of the truncated protein, probably due to nonsense-mediated decay, leading to loss of function.

Incidence and spatial distribution of adult-onset primary malignant and other central nervous system tumors in Southern Sardinia, Italy.

PURPOSE: To study for the first time the incidence of adult-onset CNS tumors in Southern Sardinia, Italy. METHODS: Clinical records of patients > 18 years old who were diagnosed with primary CNS tumors during 2016-2019 in the study area were reviewed. Meningiomas, cranial/paraspinal nerve tumors, lymphomas, and pituitary tumors were excluded. Cases were classified according to the 2016 WHO classification of CNS tumors and to the morphology codes from the International Classification of Diseases-Oncology, third edition. Age-adjusted incidence rates were calculated by the direct method to the 2011-2020 European standard population. Kulldorff's spatial scan statistic was used to identify geographic clusters of patients who shared increased/decreased tendency to develop CNS tumors. RESULTS: CNS tumors were diagnosed in 234 incident patients, but histological diagnosis was available in 222/234 patients (95%) aged 64.3 ± 13.5 years at diagnosis. Crude incidence rate was 7.1 per 100,000 persons-year (95% CI, 6.2-8.1), 6.2 per 100,000 persons-year (95% CI, 5.4-7.0) when age-adjusted. CNS tumors were more frequent in men and after age 40. Glioblastoma accounted for 76% of the total (adjusted rate, 4.7 per 100,000 persons-year; 95% CI, 4.0-5.4). Spatial analysis revealed geographic variations of glioblastoma incidence within the study area. CONCLUSION: Although the distribution of tumor diagnoses in Sardinia reflects expected age and gender-related patterns in western populations, our findings would indicate a slightly higher incidence of glial tumors, glioblastoma in particular, in Sardinia than in other European countries. The identification of spatial clusters of high/low risk will serve as a resource for etiological research.

Arterial blood gas analysis: base excess and carbonate are predictive of noninvasive ventilation adaptation and survival in amyotrophic lateral sclerosis.

Objective: To investigate the role of arterial blood gas (ABG) analysis parameters (blood carbon dioxide, pCO2; oxygen, pO2; carbonate, HCO3-; standard base excess, SBE) in monitoring respiratory function and ventilation compliance after noninvasive mechanical ventilation (NIV) adaptation, predicting survival in ALS patients. Methods: We selected the first ABG performed after NIV start in ALS patients followed from 2000 to 2015 in Turin ALS Center. Correlations between ABG parameters and survival were calculated. Risk for death/tracheostomy was computed at modifying ABG parameters by using Cox regression models, adjusted for the main prognostic factors. Kaplan-Meier curves were then performed and compared. Results: A total of 186 post-NIV ABGs were included. HCO3- and SBE showed a significant correlation with survival after NIV (respectively, R = -0.183, p = 0.018 and R = -0.200, p = 0.010). Risk for death/tracheostomy after NIV was significantly higher at increasing HCO3- and SBE blood levels, especially when HCO3- was >29 mmol/L and SBE >4 mmol/L (respectively, HR 1.466, 95% CI 1.068-2.011, p = 0.018 and HR = 1.411, 95% CI 1.030-1.32, p = 0.032). Survival in NIV was higher in patients with HCO3- < 29.0 mmol/L and SBE < 4.0 mmol/L. Conclusions: HCO3- and SBE blood levels are markers of ventilation compliance, tolerance and efficacy, being able to predict survival after NIV start in ALS.

The heterozygous deletion c.1509_1510delAG in exon 14 of FUS causes an aggressive childhood-onset ALS with cognitive impairment.

We report a case of childhood-onset ALS with a FUS gene mutation presenting cognitive impairment and a rapid clinical progression. The patient, an 11-year-old girl, presented with right distal upper limb weakness and mild intellectual disability at the Griffith Mental Development Scales. The disease rapidly worsened and the patient became tetraplegic and bed-ridden 2 years after symptom onset. A c.1509_1510delAG mutation in exon 14 of the FUS gene was detected, resulting in a predicted truncated protein, p.G504Wfs*12, lacking the nuclear localization signal. The levels of FUS mRNA in the proband were not significantly different compared to controls. Western immunoblot analysis showed that one antibody (500-526) detected in the proband ~50% of the amount of FUS protein compared to controls, while 3 other antibodies (2-27, 400-450 and FUS C-terminal), which recognize both wild type and the mutated FUS, detected 60% to 75% of the amount of the protein. These findings indicate that p.G504Wfs*12 FUS is more prone to undergo post-translational modification respect to wild type FUS.

Comorbidity of Cervical Spondylogenic Myelopathy and Amyotrophic Lateral Sclerosis: When Electromyography Makes the Difference in Diagnosis.

Cervical spondylogenic myelopathy (CSM) represents a common differential diagnosis for spinal onset Amyotrophic Lateral Sclerosis (ALS). Identifying occurrence of ALS in patients with CSM may be challenging. We evaluated the accuracy of Awaji criteria in the diagnosis of ALS in a cohort of patients with CSM. We screened all patients attending Turin ALS Center during the 2006-2018 period. We selected only patients for whom cervical cord MRI showed radiological signs of CSM. All patients underwent electromyography (EMG), and Awaji criteria were used for diagnosis of clinically probable ALS. All patients were followed up clinically for at least 6 months, and ALS diagnosis was eventually confirmed according to El-Escorial revised criteria, based on disease progression. Of 2,059 patients screened, in 42 cases, MRI showed signs of CSM; CSM incidence and prevalence risks were 0.16 and 2.04%, respectively. Based on clinical progression, 72.7% of patients were diagnosed as CSM and 27.3% as CSM + ALS. At EMG 6 (18.2%) patients fulfilled the criteria for ALS, 5 of them (83.3%) during clinical follow-up were diagnosed as clinical definite ALS + CSM. Accuracy of Awaji criteria in diagnosing ALS was good (AUC = 0.757, p = 0.03). Sensitivity and specificity of Awaji criteria were, respectively, 55.6 and 95.8%. Positive predictive value was 83.3%, while negative predictive value was 85.2%. CSM-ALS comorbidity is a relatively common problem in clinical practice. To better choose patients who could benefit from surgery, EMG should be performed in CSM patients, due to its good accuracy in recognizing ALS.

Head trauma and Parkinson's disease: results from an Italian case-control study.

We evaluated the possible association between head trauma and Parkinson's disease (PD). The FRAGAMP (Fattori di Rischio Ambientali e Genetici Associati alla Malattia di Parkinson) study is a large Italian multicenter case-control study carried out to evaluate the possible role of environmental and genetic factors in PD. Cases and controls were enrolled from six movement disorders centers located in the Central-Southern Italy. A standardized questionnaire was administered to record demographic, epidemiological, and clinical data. Positive history of head trauma was considered only if the head trauma preceded the onset of PD. All cases and controls underwent a standard neurological examination. Adjusted ORs and 95% CI were estimated using multivariate analysis (logistic regression). Four hundred ninety-two PD patients (292 men and 200 women) and 459 controls (160 men and 299 women) were enrolled in the study. A positive history for head trauma was reported by 106 (21.5%) PD patients and by 62 (13.5%) healthy controls. Multivariate analysis (OR adjusted by age, sex, family history, coffee smoking, and alcohol consumption) showed a significant positive association between PD and head trauma with an adjusted OR of 1.50 (95%CI 1.04-2.17; p value 0.03). In agreement with literature data, our study supports the positive association between head trauma and PD.

Validity of medico-administrative data related to amyotrophic lateral sclerosis in France: A population-based study.

The accuracy of French medico-administrative data concerning amyotrophic lateral sclerosis (ALS) is to date unknown. We aimed to assess the validity of hospital discharge data (HDD) and health insurance data (HID) related to ALS. A retrospective population-based study was performed. The French register of ALS in Limousin (FRALim) was used as gold standard (2000-2013 period). All patients discharged from the regional hospitals with a 'G12.2' code in their HDD (according to the International Classification of Disease-10th version) or having a G12 HID code were considered. In the study period, the register included a total of 322 incident ALS patients. Among 451 subjects identified through HDD, 290 were true incident ALS cases, corresponding to 90.1% (95% CI 86.3-93.1) sensitivity and 64.3% (95% CI 59.7-68.7) positive predictive value (PPV). A total of 184 subjects were identified through HID, 142 of which were true ALS cases. This corresponded to 44.1% (95% CI 38.6-49.7) sensitivity and 75.5% (95% CI 68.7-81.5) PPV. The combination of both HDD and HID led to 93.8% (95% CI 90.6-96.2) sensitivity and 60.8% (95% CI 56.3-65.1) PPV. This study shows that French HDD and HID, even if combined, are not per se suitable for accurate and exhaustive direct identification of ALS cases.