Potential role of vitamin D levels in amyotrophic lateral sclerosis cognitive impairment.

Cognitive impairment (CI) is common in amyotrophic lateral sclerosis (ALS): a keystone is identifying factors that could potentially modify the CI course. In recent years, vitamin D is becoming a potential modificatory factor for CI in many neurological disorders. This study aimed to highlight if vitamin D deficiency correlated with CI and clinical features in a cohort of ALS patients. We included 55 ALS patients with a neuropsychological evaluation (classified with the Strong Criteria) and a vitamin D dosage at the diagnosis. We also reviewed medical records and completed data for medical history, physical and neurological examination, and functional scales. At the diagnosis, 30 patients (54%) had CI. Most patients (82%) displayed low vitamin D levels (19.87 ± 9.80 ng/ml). Comparing the vitamin D level between patients with and without CI, we observed significantly lower values in the first group (15.8 ± 8.2 vs. 22.0 ± 9.7 ng/ml, p: 0.04). In the spinal female subgroup (n = 15), we found an inverse correlation between vitamin D and bizarreness score in the cognitive estimates test (r = 0.58; p: 0.04) and a positive correlation with the Corrected Raven's Standard Progressive Matrices (r = 0.53, p: 0.04). Conversely, in the bulbar female group, we observed a correlation with the corrected direct span (r = 0.84, p: 0.03). With the log-rank survival analysis, we found that the patients with vitamin D < 10 ng/ml had a shorter disease duration (Chi: 5.78, p: 0.02). Our results indicate that levels of vitamin D can influence the cognitive status of people living with ALS and that severe deficits might be an adverse prognostic survival factor.

Susac Syndrome: an uncommon cause of impaired vision.

A 35-year-old Caucasian woman presented an abrupt onset of bilateral impaired vision, and arrived to our attention two weeks later. She had a previous episode of mild dizziness. She underwent a fluorescein angiography showing branch retinal artery occlusions and a brain magnetic resonance imaging (MRI) revealing several supraand infratentorial FLAIR-hyperintense white matter lesions, two with contrast enhancement. Thrombophilic, autoimmune and infective (including Human Immunodeficiency Virus, Borrelia burgdorferi, Hepatitis B Virus, Hepatitis C Virus, Herpes Simplex Virus 1-2, Varicella Zoster Virus) screening was negative. Cerebrospinal fluid analysis showed intrathecal IgG synthesis. We suspected a Primary Central Nervous System Vasculitis, and intravenous steroids were started. Three months later a second brain MRI showed seven new lesions without contrast enhancement, and she revealed a cognitive impairment and bilateral hearing loss. Reviewing the clinical history and MRI, she fulfilled diagnostic criteria for Susac syndrome. She had two cycles of cyclophosphamide, and recovered in 6 months and then remained stable with metotrexate.

Neurological emergency at the COVID-19 pandemic: report from a referral hospital in Eastern Piedmont, Italy.

BACKGROUND: The pandemic implied dramatic changes in public health assets. In Italy, some Stroke Units were transformed into sub-intensive COVID-19 Units, making the management of neurological patients demanding. We described how the flow of neurological emergencies was affected by the pandemic impact. METHODS: We analyzed accesses to the Emergency Department (ED) of the "Maggiore della Carità" Hospital, Piedmont, Italy, during a period of 8 months (COVID time; March to May 2020 and October 2020 to February 2021) and analyzed the admissions to the Neurology Unit and the underlying diagnosis. We also evaluated potential changes in the treatment of acute ischemic stroke in the same period. These variables were compared with two equivalent periods of time (2019-2020; 2018-2019). RESULTS: During the COVID time, there was a clear-cut reduction of the total ED accesses compared to NoCOVID times. However, admissions for acute neurological conditions showed a mild but non-significant decrease (6.3%vs.7.3%). The same applied to acute ischemic stroke, which represented the most common condition (47.7%). The proportion of patients who underwent emergent reperfusion therapies remained unchanged. Furthermore, no difference was found in door-to-needle and door-to-groin intervals between COVID time and NoCOVID times. On the contrary, the onset-to-door interval was significantly longer during the COVID time (p value: 0.001). DISCUSSION: While the percentage of admissions following an ED access grew dramatically, those to the Neurology Unit showed overall only a slight non-significant decrease. This finding implicitly reflects the serious and urgent nature of many neurological diseases, compelling people to access EDs at any time.

Paraneoplastic neuromyelitis optica spectrum disorders: a case series.

Aquaporin-4 antibody (AQP4-IgG) neuromyelitis optica spectrum disorders (NMOSD) are rare idiopathic autoimmune diseases, presenting with optic neuritis (ON), longitudinally extensive transverse myelitis (LETM), and brainstem syndromes and a prevalence range between 0.5 and 4/100,000. Only 3% to 25% of NMOSD have been described as a paraneoplastic (PN) syndrome (PNNMOSD). Both idiopathic NMOSD (INMOSD) and PNNMOSD cases mostly affect females, but PNNMOSD usually presents with a spinal cord or brainstem involvement in elderly patients. Few cases of both malignancies (for the majority breast or lung cancer) and benign tumors (monoclonal gammopathy) were previously reported. Currently, there is no consensus on treatment approach for PNNMOSD (only surgical removal or surgery combined with chronic immunosuppression). Here, we present a series of three newly diagnosed PNNMOSD cases, who differ from each other for demographic and clinical features, tumor association, long-term treatment, and outcome. We propose that a PN etiology should be considered always whenever a new diagnosis of NMOSD is made, not only in patients over 50 years old or in spinal cord/brainstem lesions presentations. Our findings add to existing evidence and raise awareness on PNNMOSD. We enhance the importance for the clinicians of recognizing tumor symptoms and signs whenever a NMOSD is newly diagnosed.

Cannabinoids in multiple sclerosis: A neurophysiological analysis.

OBJECTIVES: To investigate the action of cannabinoids on spasticity and pain in secondary progressive multiple sclerosis, by means of neurophysiological indexes. MATERIAL AND METHODS: We assessed 15 patients with progressive MS (11 females) using clinical scales for spasticity and pain, as well as neurophysiological variables (H/M ratio, cutaneous silent period or CSP). Testing occurred before (T0) and during (T1) a standard treatment with an oral spray containing delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Neurophysiological measures at T0 were compared with those of 14 healthy controls of similar age and sex (HC). We then compared the patient results at the two time points (T1 vs T0). RESULTS: At T0, neurophysiological variables did not differ significantly between patients and controls. At T1, spasticity and pain scores improved, as detected by the Modified Ashworth Scale or MAS (P = .001), 9-Hole Peg Test or 9HPT (P = .018), numeric rating scale for spasticity or NRS (P = .001), and visual analogue scale for pain or VAS (P = .005). At the same time, the CSP was significantly prolonged (P = .001). CONCLUSIONS: The THC-CBD spray improved spasticity and pain in secondary progressive MS patients. The spray prolonged CSP duration, which appears a promising tool for assessing and monitoring the analgesic effects of THC-CBD in MS.

Gas6/TAM system as potential biomarker for multiple sclerosis prognosis.

Introduction: The protein growth arrest-specific 6 (Gas6) and its tyrosine kinase receptors Tyro-3, Axl, and Mer (TAM) are ubiquitous proteins involved in regulating inflammation and apoptotic body clearance. Multiple sclerosis (MS) is the most common inflammatory demyelinating disease of the central nervous system leading to progressive and irreversible disability if not diagnosed and treated promptly. Gas6 and TAM receptors have been associated with neuronal remyelination and stimulation of oligodendrocyte survival. However, few data are available regarding clinical correlation in MS patients. We aimed to evaluate soluble levels of these molecules in the cerebrospinal fluid (CSF) and serum at MS diagnosis and correlate them with short-term disease severity. Methods: In a prospective cohort study, we enrolled 64 patients with a diagnosis of clinical isolated syndrome (CIS), radiological isolated syndrome (RIS) and relapsing-remitting (RR) MS according to the McDonald 2017 Criteria. Before any treatment initiation, we sampled the serum and CSF, and collected clinical data: disease course, presence of gadolinium-enhancing lesions, and expanded disability status score (EDSS). At the last clinical follow-up, we assessed EDSS and calculated MS severity score (MSSS) and age-related MS severity (ARMSS). Gas6 and TAM receptors were determined using an ELISA kit (R&D Systems) and compared to neurofilament (NFLs) levels evaluated with SimplePlex™ fluorescence-based immunoassay. Results: At diagnosis, serum sAxl was higher in patients receiving none or low-efficacy disease-modifying treatments (DMTs) versus patients with high-efficacy DMTs (p = 0.04). Higher CSF Gas6 and serum sAXL were associated with an EDSS <3 at diagnosis (p = 0.04; p = 0.037). Serum Gas6 correlates to a lower MSSS (r2 = -0.32, p = 0.01). Serum and CSF NFLs were confirmed as disability biomarkers in our cohort according to EDSS (p = 0.005; p = 0.002) and MSSS (r2 = 0.27, p = 0.03; r2 = 0.39, p = 0.001). Results were corroborated using multivariate analysis. Conclusions: Our data suggest a protective role of Gas6 and its receptors in patients with MS and suitable severity disease biomarkers.

Early Predictors of Disability and Cognition in Multiple Sclerosis Patients: A Long-Term Retrospective Analysis.

We conducted a retrospective analysis on multiple sclerosis (MS) patients with perceived cognitive decline and long disease duration to investigate early predictors of future cognitive impairment (CI) and motor disability. Sixty-five patients complaining of cognitive decline were assessed with an extensive neuropsychological battery at the last clinical follow-up and classified as mildly impaired, severely impaired, and cognitively spared based on the results. Motor disability was assessed with EDSS, MSSS, and ARMSS. Baseline demographic, clinical, and imaging parameters were retrospectively collected and inserted in separate multivariate regression models to investigate the predictive power of future impairment. Twenty-one patients (32.3%) showed no CI, seventeen (26.2%) showed mild CI, and twenty-seven (41.5%) showed severe CI. Older and less educated patients with higher EDSS, longer disease duration, and higher white matter lesion load (WMLL) at diagnosis (particularly with cerebellar involvement) were more likely to develop CI after a mean follow-up from diagnosis of 16.5 ± 6.9 years. DMT exposure was protective. The multivariate regression analyses confirmed WMLL, disease duration, and educational levels as the parameters with significant predictive value for future CI (R2 adjusted: 0.338 p: 0.001). Older patients with progressive phenotype both at diagnosis and T1 were more likely to be not fully ambulatory at T1 (R2 adjusted: 0.796 p: 0.0001). Our results further expand knowledge on early predictors of cognitive decline and evolution over time.

Prognostic Role of Visual Evoked Potentials in Non-Neuritic Eyes at Multiple Sclerosis Diagnosis.

Introduction: This study aimed to assess the prognostic role of visual evoked potentials (VEPs) of the non-neuritic eye at the diagnosis of multiple sclerosis (MS). Patients and methods: We enrolled 181 MS patients (62% females, mean age at diagnosis: 38 years, standard deviation: 12) at the time of the first diagnostic work-up, including VEPs. We collected P100 latency and N75-P100 amplitude of non-neuritic eyes at diagnosis, and then we calculated the mean values in 127 patients with no history of optic neuritis (ON) or considered the unaffected eye in the remaining. At last follow-up (minimum: one year), disability was evaluated according to MS Severity Score or MSSS (median: 2.44, range: 0.18-9.63). Statistical analysis included Mann-Whitney descriptive analysis, Spearman correlation for independent samples, and linear regression for significant predictors of MSSS. Results: 38/181 patients had P100 latency >115 ms, and 63/181 showed N75-P100 amplitude < 5 microV in the unaffected eyes at MS diagnosis. At last follow-up, MSSS correlated with P100 latency (rho = 0.21, p = 0.004) and N75-P100 amplitude (rho = 0.19, p = 0.009) collected at diagnosis. P100 latency (not N75-P100 amplitude) resulted in a predictor for disability over time (MSSS) in the regression model (along with age at onset, MS course, and disease-modifying treatments). Conclusions: Our study showed a prognostic value of VEPs in clinically unaffected eyes at MS diagnosis to predict future disability, independently from a history of ON.

Aging in multiple sclerosis: from childhood to old age, etiopathogenesis, and unmet needs: a narrative review.

Multiple sclerosis (MS) primarily affects adult females. However, in the last decades, rising incidence and prevalence have been observed for demographic extremes, such as pediatric-onset MS (POMS; occurring before 18 years of age) and late-onset MS (corresponding to an onset above 50 years). These categories show peculiar clinical-pathogenetic characteristics, aging processes and disease courses, therapeutic options, and unmet needs. Nonetheless, several open questions are still pending. POMS patients display an important contribution of multiple genetic and environmental factors such as EBV, while in LOMS, hormonal changes and pollution may represent disease triggers. In both categories, immunosenescence emerges as a pathogenic driver of the disease, particularly for LOMS. In both populations, patient and caregiver engagement are essential from the diagnosis communication to early treatment of disease-modifying therapy (DMTs), which in the elderly population appears more complex and less proven in terms of efficacy and safety. Digital technologies (e.g., exergames and e-training) have recently emerged with promising results, particularly in treating and following motor and cognitive deficits. However, this offer seems more feasible for POMS, being LOMS less familiar with digital technology. In this narrative review, we discuss how the aging process influences the pathogenesis, disease course, and therapeutic options of both POMS and LOMS. Finally, we evaluate the impact of new digital communication tools, which greatly interest the current and future management of POMS and LOMS patients.

COVID-19 Vaccination and Late-Onset Myasthenia Gravis: A New Case Report and Review of the Literature.

Myasthenia gravis (MG) is a rare autoimmune disease that is potentially threatening for patient life. Auto-antibodies targeting structures of the neuromuscular junction, particularly the acetylcholine receptor (AchR), are often found in the serum of MG patients. New-onset MG after SARS-CoV-2 vaccination has rarely been reported since the introduction of vaccination. Infections and COVID-19 infection have also been reported as possible triggers for a myasthenic crisis. We report a case of new-onset MG after receiving the mRNA COVID-19 vaccination. The patient was a 73-year-old male initially presenting with ocular symptoms and a rapid generalization. We also performed a literature revision of 26 described cases of MG after SARS-CoV-2 immunization. The patients were a majority of males with generalized late-onset MG occurring after the first dose of vaccine, similar to our patient. Only our patient showed a thymoma. Thymic mass and the positivity of AchR antibodies suggest that vaccination might have triggered a subclinical pre-existing MG with symptoms flaring. Clinicians should be aware of possible new-onset MG after COVID-19 vaccination, particularly in at-risk patients. Even though COVID-19 vaccination should be recommended in MG patients, particularly in well-compensated patients. However, more studies need to be performed in the future.

Safety of COVID-19 Vaccines: Spotlight on Neurological Complications.

The COVID-19 pandemic has led to unprecedented demand on the global healthcare system. Remarkably, at the end of 2021, COVID-19 vaccines received approvals for human use in several countries worldwide. Since then, a solid base for response in the fight against the virus has been placed. COVID-19 vaccines have been shown to be safe and effective drugs. Nevertheless, all kinds of vaccines may be associated with the possible appearance of neurological complications, and COVID-19 vaccines are not free from neurological side effects. Neurological complications of COVID-19 vaccination are usually mild, short-duration, and self-limiting. However, severe and unexpected post-vaccination complications are rare but possible events. They include the Guillain-Barré syndrome, facial palsy, other neuropathies, encephalitis, meningitis, myelitis, autoimmune disorders, and cerebrovascular events. The fear of severe or fatal neurological complications fed the "vaccine hesitancy" phenomenon, posing a vital communication challenge between the scientific community and public opinion. This review aims to collect and discuss the frequency, management, and outcome of reported neurological complications of COVID-19 vaccines after eighteen months of the World Health Organization's approval of COVID-19 vaccination, providing an overview of safety and concerns related to the most potent weapon against the SARS-CoV-2.

The Role of Tau beyond Alzheimer's Disease: A Narrative Review.

Nowadays, there is a need for reliable fluid biomarkers to improve differential diagnosis, prognosis, and the prediction of treatment response, particularly in the management of neurogenerative diseases that display an extreme variability in clinical phenotypes. In recent years, Tau protein has been progressively recognized as a valuable neuronal biomarker in several neurological conditions, not only Alzheimer's disease (AD). Cerebrospinal fluid and serum Tau have been extensively investigated in several neurodegenerative disorders, from classically defined proteinopathy, e.g., amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Parkinson's disease (PD), but also in inflammatory conditions such as multiple sclerosis (MS), as a marker of axonal damage. In MS, total Tau (t-Tau) may represent, along with other proteins, a marker with diagnostic and prognostic value. In ALS, t-Tau and, mainly, the phosphorylated-Tau/t-Tau ratio alone or integrated with transactive DNA binding protein of ~43 kDa (TDP-43), may represent a tool for both diagnosis and differential diagnosis of other motoneuron diseases or tauopathies. Evidence indicated the crucial role of the Tau protein in the pathogenesis of PD and other parkinsonian disorders. This narrative review summarizes current knowledge regarding non-AD neurodegenerative diseases and the Tau protein.

Cerebrospinal fluid biomarkers and cognitive functions at multiple sclerosis diagnosis.

Cognitive impairment (CI) is a frequent and disabling symptom in Multiple Sclerosis (MS). Axonal damage may contribute to CI development from early stages. Nevertheless, no biomarkers are at the moment available to track CI in MS patients. We aimed to explore the correlation of cerebrospinal fluid (CSF) axonal biomarkers, in particular: light-chain neurofilaments (NFL), Tau, and Beta-amyloid protein (Abeta) in MS patients with CI at the diagnosis. 62 newly diagnosed MS patients were enrolled, and cognition was evaluated using the Brief International Cognitive Assessment for MS (BICAMS) battery. CSF NFL, Abeta, and Tau levels were determined with commercial ELISA. Patients with CI (45.1%) did not differ for demographic, clinical, and MRI characteristics (except for lower educational level), but they displayed greater neurodegeneration, exhibiting higher mean CSF Tau protein (162.1 ± 52.96 pg/ml versus 132.2 ± 63.86 pg/ml p:0.03). No differences were observed for Abeta and NFL. The number of impaired tests and Tau were significantly correlated (r:0.32 p:0.01). Tau was higher in particular in patients with slowed information processing speed (IPS) (p:0.006) and a linear regression analysis accounting for EDSS, MRI, and MS subtype confirmed Tau as a weak predictor of IPS and cognitive impairment. In conclusion, CI has an important burden on the quality of life of MS patients and should be looked for even at diagnosis. Axonal damage biomarkers, and in particular Tau, seem to reflect cognition impairment in the early stages.

Efficacy of Cannabinoids on Spasticity and Chronic Pain in a Patient with Co-occurrence of Multiple Sclerosis and Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disease involving the skin and central nervous system (CNS), and also characterized by skeletal and spinal schwannomas that may cause chronic neurogenic pain. Furthermore, pain in NF1 is underestimated, even though it has an impact on quality of life. Multiple sclerosis (MS) is the most common acquired demyelinating disease that may in later stages present with refractory spasticity, particularly in the lower limbs. Oromucosal cannabinoid sprays are currently available for spasticity treatment in MS, with encouraging results on MS pain, but few data have been reported regarding the use of cannabinoids in NF1. We report the successful treatment of chronic neurogenic pain and spasticity in a patient with co-occurrence of NF1 and MS after a poor response to standard approaches. LEARNING POINTS: Chronic pain is a possible complication of several neurological conditions and may show a poor response to standard drugs, thus affecting quality of life.Oromucosal cannabinoid sprays are routinely used in multiple sclerosis spasticity.Cannabinoids may be also effective against neurogenic pain in neurofibromatosis type 1.

Cerebrospinal Tau levels as a predictor of early disability in multiple sclerosis.

INTRODUCTION: Axonal loss is an important feature of Multiple Sclerosis (MS), being strongly related to irreversible disability accumulation. Nonetheless, the exact mechanisms underlying axonal loss remain unclear. Cerebrospinal fluid (CSF) levels of Tau and Beta-amyloid (Abeta) currently represent diagnostic biomarkers in other neurodegenerative diseases. In MS, studies on CSF Tau and Abeta provided preliminary informations on disease prognosis, but results have not yet been replicated. METHODS: We investigated whether CSF Tau and Abeta levels could predict early disability accumulation in MS patients. 100 patients underwent CSF analysis during their diagnostic work-up. Demographic, clinical, radiological features and CSF were collected at baseline. MS severity score (MSSS) and age-related MSSS (ARMSS) were calculated at last follow-up. We performed Mann-Whitney test, Spearman's coefficient, and multiple regression analysis for significant predictors of disability based on CSF Abeta and Tau levels, gender, age at diagnosis and MRI characteristics at baseline. RESULTS: Baseline CSF Tau levels moderately correlated with MSSS (r=0.372 p=0.0001) and weakly with ARMSS (r=0.237 p=0.0176) after a mean two years follow-up. Predictors of early disability evaluated with MSSS and ARMSS were CSF Tau (Beta:0.258 p=0.009 and Beta:0.252 p=0.01) and spinal cord involvement (Beta:0.196 p=0.029 and Beta:0.240 p=0.008); as well as age at MS diagnosis (Beta:0.286 p=0.001) for MSSS, and high brain lesion load (Beta:0.207 p=0.02) for ARMSS. CONCLUSION: CSF Tau levels at diagnosis possibly has a predictive value along with MRI features and age at diagnosis. We hypothesize that Tau levels may express chronic axonal damage, possibly contributing to early MS disability.

Serum Vitamin D as a Marker of Impaired Information Processing Speed and Early Disability in Multiple Sclerosis Patients.

Slowed information processing speed (IPS) is the hallmark and first cognitive domain to be altered in multiple sclerosis (MS) patients. Insufficient serum vitamin D was previously associated with disease development, relapses, and progression, but little is reported on cognition. However, vitamin D and cognitive impairment (CI) in other neurodegenerative diseases have already been linked. We explored the possible correlation between vitamin D and IPS at diagnosis and early disability at last follow-up in 81 MS patients. At diagnosis, we collected vitamin D levels and performed a Symbol Digit Modalities Test (SDMT). Raw scores were adjusted for age, gender, and educational level. Early disability was evaluated with MS severity score (MSSS) and age-related MSSS (ARMSS). A total of 71 patients (86.58%) showed hypovitaminosis D (19.71 ± 8.76 ng/mL) and 18 patients (21.95%) had CI. Patients with CI showed severe hypovitaminosis D (p = 0.004). No patients with sufficient vitamin D levels had CI. We found a positive correlation between vitamin D levels at diagnosis and (1) SDMT raw and z-score that persisted after correction for sunlight exposure and MRI baseline characteristics, and (2) EDSS, MSSS, and ARMSS after a mean 2 year follow-up. Low vitamin D levels may affect both cognition and early disability in newly diagnosed MS patients.

The Yin-Yang of osteopontin in nervous system diseases: damage versus repair.

Osteopontin is a broadly expressed pleiotropic protein, and is attracting increased attention because of its role in the pathophysiology of several inflammatory, degenerative, autoimmune, and oncologic diseases. In fact, in the last decade, several studies have shown that osteopontin contributes to tissue damage not only by recruiting harmful inflammatory cells to the site of lesion, but also increasing their survival. The detrimental role of osteopontin has been indeed well documented in the context of different neurological conditions (i.e., multiple sclerosis, Parkinson's, and Alzheimer's diseases). Intriguingly, recent findings show that osteopontin is involved not only in promoting tissue damage (the Yin), but also in repair/regenerative mechanisms (the Yang), mostly triggered by the inflammatory response. These two apparently discordant roles are partly related to the presence of different functional domains in the osteopontin molecule, which are exposed after thrombin or metalloproteases cleavages. Such functional domains may in turn activate intracellular signaling pathways and mediate cell-cell and cell-matrix interactions. This review describes the current knowledge on the Yin and Yang features of osteopontin in nervous system diseases. Understanding the mechanisms behind the Yin/Yang would be relevant to develop highly specific tools targeting this multifunctional protein.

Contribution of Rare and Low-Frequency Variants to Multiple Sclerosis Susceptibility in the Italian Continental Population.

Genome-wide association studies identified over 200 risk loci for multiple sclerosis (MS) focusing on common variants, which account for about 50% of disease heritability. The goal of this study was to investigate whether low-frequency and rare functional variants, located in MS-established associated loci, may contribute to disease risk in a relatively homogeneous population, testing their cumulative effect (burden) with gene-wise tests. We sequenced 98 genes in 588 Italian patients with MS and 408 matched healthy controls (HCs). Variants were selected using different filtering criteria based on allelic frequency and in silico functional impacts. Genes showing a significant burden (n = 17) were sequenced in an independent cohort of 504 MS and 504 HC. The highest signal in both cohorts was observed for the disruptive variants (stop-gain, stop-loss, or splicing variants) located in EFCAB13, a gene coding for a protein of an unknown function (p < 10-4). Among these variants, the minor allele of a stop-gain variant showed a significantly higher frequency in MS versus HC in both sequenced cohorts (p = 0.0093 and p = 0.025), confirmed by a meta-analysis on a third independent cohort of 1298 MS and 1430 HC (p = 0.001) assayed with an SNP array. Real-time PCR on 14 heterozygous individuals for this variant did not evidence the presence of the stop-gain allele, suggesting a transcript degradation by non-sense mediated decay, supported by the evidence that the carriers of the stop-gain variant had a lower expression of this gene (p = 0.0184). In conclusion, we identified a novel low-frequency functional variant associated with MS susceptibility, suggesting the possible role of rare/low-frequency variants in MS as reported for other complex diseases.

K Index is a Reliable Marker of Intrathecal Synthesis, and an Alternative to IgG Index in Multiple Sclerosis Diagnostic Work-Up.

The K free light chain (K) index has been suggested as a reliable marker of intrathecal synthesis,despite the 2017 McDonald criteria for multiple sclerosis (MS) suggesting to "interpret with caution positiveimmunoglobulin G (IgG) index when testing for oligoclonal bands (OB) is negative or not performed". Theaim of this study was to compare the performance of K and IgG indexes for MS diagnosis and OB detectionin a cohort of Italian patients. We enrolled 385 patients (127 MS, 258 non-MS) who had cerebrospinal fluid(CSF) analysis, including isoelectric focusing (IEF), to detect OB in the diagnostic work-up. Albumin, IgGand free light chains were measured by nephelometry and used to calculate IgG and K indexes. Althoughthe two markers were highly related (r = 0.75, r2 = 0.55, p < 0.0001), the K index showed greater sensitivity andnegative predictive value (versus the IgG index) for OB detection (97% versus 48% and 97% versus 71%) andMS diagnosis (96% versus 50% and 98% versus 78%). These results support K index (and not IgG index) as afirst-line marker for MS, followed by IEF, according to a sequential testing approach in CSF analysis.