Identification of genetic risk loci and prioritization of genes and pathways for myasthenia gravis: a genome-wide association study.

Myasthenia gravis is a chronic autoimmune disease characterized by autoantibody-mediated interference of signal transmission across the neuromuscular junction. We performed a genome-wide association study (GWAS) involving 1,873 patients diagnosed with acetylcholine receptor antibody-positive myasthenia gravis and 36,370 healthy individuals to identify disease-associated genetic risk loci. Replication of the discovered loci was attempted in an independent cohort from the UK Biobank. We also performed a transcriptome-wide association study (TWAS) using expression data from skeletal muscle, whole blood, and tibial nerve to test the effects of disease-associated polymorphisms on gene expression. We discovered two signals in the genes encoding acetylcholine receptor subunits that are the most common antigenic target of the autoantibodies: a GWAS signal within the cholinergic receptor nicotinic alpha 1 subunit (CHRNA1) gene and a TWAS association with the cholinergic receptor nicotinic beta 1 subunit (CHRNB1) gene in normal skeletal muscle. Two other loci were discovered on 10p14 and 11q21, and the previous association signals at PTPN22, HLA-DQA1/HLA-B, and TNFRSF11A were confirmed. Subgroup analyses demonstrate that early- and late-onset cases have different genetic risk factors. Genetic correlation analysis confirmed a genetic link between myasthenia gravis and other autoimmune diseases, such as hypothyroidism, rheumatoid arthritis, multiple sclerosis, and type 1 diabetes. Finally, we applied Priority Index analysis to identify potentially druggable genes/proteins and pathways. This study provides insight into the genetic architecture underlying myasthenia gravis and demonstrates that genetic factors within the loci encoding acetylcholine receptor subunits contribute to its pathogenesis.

Nabiximols discontinuation rate in a large population of patients with multiple sclerosis: a 18-month multicentre study.

INTRODUCTION: Delta-δ-tetrahydrocannabinol and cannabidiol (THC:CBD) oromucosal spray is used as an add-on therapy option for moderate to severe multiple sclerosis (MS) spasticity resistant to other medications. Aims of this study were to provide real-life data on long-term clinical outcomes in a large population of Italian patients treated with THC:CBD and to evaluate predictors of THC:CBD therapy continuation. MATERIALS AND METHODS: This prospective observational multicentre Italian study screened all patients with MS consecutively included in the Agenzia Italiana del Farmaco e-registry at the start of THC:CBD treatment (baseline), after 4 weeks (T1), 12±3 weeks (T2), 24±3 weeks (T3), 48±3 weeks (T4) and 72±3 weeks (T5) from baseline. RESULTS: A total of 1845 patients were recruited from 32 MS Italian centres. At T1, 1502 (81.4%) of patients reached a Numerical Rating Scale (NRS) improvement of ≥20%, with an NRS reduction of 26.9% at T1 and of 34.4% at T5. At T5, 725 patients (48.3% of 1502) discontinued treatment with highest discontinuation rate at T2 and T3. Daily number of puffs was generally stable through the observation period. The multivariate analysis showed that higher NRS scores at baseline (OR 2.28, 95% CI 1.15 to 6.36, p<0.01) and higher differences of NRS between T0 and T1 (OR 2.11, 95% CI 1.08 to 8.26, p<0.05) were associated with an increased probability to continue therapy after 18 months. DISCUSSION: THC:CBD effects were sustained for 18 months with a relatively stable number of puffs per day. About 50% of patients abandoned THC:CBD therapy for loss of efficacy or adverse events.

Effects of THC/CBD oromucosal spray on spasticity-related symptoms in people with multiple sclerosis: results from a retrospective multicenter study.

INTRODUCTION: The approval of 9-δ-tetrahydocannabinol (THC)+cannabidiol (CBD) oromucosal spray (Sativex®) in Italy as an add-on medication for the management of moderate to severe spasticity in multiple sclerosis (MS) has provided a new opportunity for MS patients with drug-resistant spasticity. We aimed to investigate the improvement of MS spasticity-related symptoms in a large cohort of patients with moderate to severe spasticity in daily clinical practice. MATERIALS AND METHODS: MS patients with drug-resistant spasticity were recruited from 30 Italian MS centers. All patients were eligible for THC:CBD treatment according to the approved label: ≥ 18 years of age, at least moderate spasticity (MS spasticity numerical rating scale [NRS] score ≥ 4) and not responding to the common antispastic drugs. Patients were evaluated at baseline (T0) and after 4 weeks of treatment (T1) with the spasticity NRS scale and were also asked about meaningful improvements in 6 key spasticity-related symptoms. RESULTS: Out of 1615 enrolled patients, 1432 reached the end of the first month trial period (T1). Of these, 1010 patients (70.5%) reached a ≥ 20% NRS score reduction compared with baseline (initial responders; IR). We found that 627 (43.8% of 1432) patients showed an improvement in at least one spasticity-related symptom (SRSr group), 543 (86.6%) of them belonging to the IR group and 84 (13.4%) to the spasticity NRS non-responders group. CONCLUSION: Our study confirmed that the therapeutic benefit of cannabinoids may extend beyond spasticity, improving spasticity-related symptoms even in non-NRS responder patients.

Thymoma-associated myasthenia gravis: Clinical features and predictive value of antiacetylcholine receptor antibodies in the risk of recurrence of thymoma.

BACKGROUND: Thymoma-associated myasthenia gravis (TAMG) is one of the subtypes of myasthenia gravis with autoantibodies against the acetylcholine receptor (AChR-Ab). We analyzed the clinical features of our cohort of TAMG patients and the changes in AChR-Ab titer before and after thymectomy in order to identify factors predicting thymoma relapses. METHODS: We retrospectively assessed: age of MG onset, MG clinical status according to MGFA (Myasthenia Gravis Foundation of America), epoch of thymectomy, post-thymectomy status, oncological features and surgical approach. AChR-Ab dosages were measured both before and after thymectomy. Linear regression models were applied to identify clinical determinants of AChR-Ab titers and the Cox regression model was fitted to estimate the factors associated with the risk of thymoma recurrence. RESULTS: The study sample included 239 MG patients, 27 of whom experienced one or more recurrences (median follow-up time: 4.8 years). The AChR-Ab titers decreased after first thymectomy (P < 0.001); the decrease was more pronounced in female patients (P = 0.05), in patients diagnosed with MG at an older age (P = 0.003), and in those who had lower MG stage before surgery (P = 0.02) or higher Masaoka-Koga stage (P = 0.005). The risk of relapse was closely linked with the age of the patient, the Masaoka-Koga stage and the surgical approach. CONCLUSIONS: Presurgery levels of AChR-Ab or their change after surgery were not associated with thymoma recurrence. The reduction of AChR-Ab titers after thymectomy confirms an immunological role of thymoma in the pathogenesis of MG. KEY POINTS: Significant findings of the study: Young MG patients with an advanced Masaoka staging score of the primary tumor who underwent thymectomy with approaches different from sternotomy and VATS should be monitored for high risk of recurrence. WHAT THIS STUDY ADDS: No other study has ever investigated the changes in AChR-Ab titers before and after thymectomy in a large cohort of TAMG patients. The reduction of AChR-Ab titers after thymectomy suggests an immunological role of thymoma in the pathogenesis of MG.

Disappearance of Anti-Thyroid Autoantibodies following Thymectomy in Patients with Myasthenia Gravis.

OBJECTIVES: The thymus plays a central role in immune tolerance, which prevents autoimmunity. Myasthenia gravis (MG) is commonly associated with thymoma or thymus hyperplasia, and it can coexist with autoimmune thyroid diseases. However, the role of the thymus in thyroid autoimmunity remains to be clarified, which we investigated here. STUDY DESIGN: The study design entailed the inclusion of consecutive MG patients and the measurement of anti-thyroid autoantibodies at baseline and, limited to autoantibody-positive patients, also at 24 and 48 weeks. One hundred and seven MG patients were studied. The main outcome measure was the behaviour of anti-thyroglobulin autoantibodies (TgAbs) and anti-thyroperoxidase autoantibodies (TPOAbs) over time in relation to thymectomy. RESULTS: Serum TgAbs and/or TPOAbs were detected in ∼20% of patients in the absence of thyroid dysfunction. The prevalence of positive serum TgAbs and/or TPOAbs decreased significantly (p = 0.002) over the follow-up period in patients who underwent thymectomy, but not in patients who were not thymectomized. When the analysis was restricted to TgAbs or TPOAbs, findings were similar. On the same line, there was a general trend towards a reduction in the serum concentrations of anti-thyroid autoantibodies in patients who underwent thymectomy, which was significant for TPOAbs (p = 0.009). CONCLUSIONS: Our findings suggest a role of the thymus in the maintenance of humoral thyroid autoimmunity.

Investigation of MLH1, MGMT, CDKN2A, and RASSF1A Gene Methylation in Thymomas From Patients With Myasthenia Gravis.

A feature of thymomas is their frequent association with myasthenia gravis (MG), an autoimmune disease characterized by the production of autoantibodies directed to different targets at the neuromuscular junction. Indeed, almost 30-40% of thymomas are found in patients with a type of MG termed thymoma-associated MG (TAMG). Recent studies suggest that TAMG-associated thymomas could represent a molecularly distinct subtype of thymic epithelial tumors (TETs), but few data are still available concerning the epigenetic modifications occurring in TAMG tissues. The promoter methylation levels of DNA repair (MLH1 and MGMT) and tumor suppressor genes (CDKN2A and RASSF1A) have been frequently investigated in TETs, but methylation data in TAMG tissues are scarce and controversial. To further address this issue, we investigated MLH1, MGMT, CDKN2A, and RASSF1A methylation levels in blood samples and surgically resected thymomas from 69 patients with TAMG and in the adjacent normal thymus available from 44 of them. Promoter methylation levels of MLH1, MGMT, CDKN2A, and RASSF1A genes were not increased in cancer with respect to healthy tissues and did not correlate with the histological or pathological features of the tumor or with the MG symptoms. The present study suggests that hypermethylation of these genes is not frequent in TAMG tissues.

Sativex in resistant multiple sclerosis spasticity: Discontinuation study in a large population of Italian patients (SA.FE. study).

BACKGROUND: The approval of Sativex for the management of multiple sclerosis (MS) spasticity opened a new opportunity to many patients. In Italy, the healthcare payer can be fully reimbursed by the involved pharma company with the cost of treatment for patients not responding after a 4 week (28 days) trial period (Payment by Results, PbR), and 50% reimbursed with the cost of 6 weeks (42 days) treatment for other patients discontinuing (Cost Sharing, CS). The aim of our study was to describe the Sativex discontinuation profile from a large population of spasticity treated Italian MS patients. METHODS: We collected data of patients from 30 MS centres across the country starting Sativex between January 2014 and February 2015. Data were collected from the mandatory Italian Medicines Agency (AIFA) web-registry. Predictors of treatment discontinuation were assessed using a multivariate Cox proportional regression analysis. RESULTS: During the observation period 631 out of 1597 (39.5%) patients discontinued Sativex. The Kaplan-Meier estimates curve showed that 333 patients (20.8%) discontinued treatment at 4 weeks while 422 patients (26.4%) discontinued at 6 weeks. We found after adjusted modeling that a higher NRS score at T1 (adjHR 2.23, 95% 2.07-2.41, p<0.001) and a lower baseline NRS score (adjHR 0.51 95% CI 0.46-0.56, p<0.001) were predictive of treatment discontinuation. CONCLUSION: These data show that the first 6 weeks are useful in identifying those patients in which Sativex could be effective, thus avoiding the cost of longer term evaluation.

Hereditary spastic paraparesis in adults. A clinical and genetic perspective from Tuscany.

OBJECTIVE: Hereditary spastic paraparesis or paraplegias (HSPs) are a group of neurogenetic conditions with prominent involvement of the pyramidal tracts. Aim of this study is the clinical and molecular characterization of a cohort of patients with HSP. Moreover, we aim to study the minimum prevalence of HSP in our area and to propose a schematic diagnostic approach to HSP patients based on the available data from the literature. METHODS: Retrospective/perspective study on the subjects with clinical signs and symptoms indicative of pure or complicated HSP, in whom other possible diagnosis were excluded by appropriate neuroradiological, neurophysiologic and laboratory studies, who have been evaluated by the Neurogenetic Service of our Clinic in last two years (2011-2012). RESULTS: 45 patients were identified. The minimum prevalence of HSP in our area was of about 2.17-3.43/100,000. The SF-36 (quality of life) and SPRS (disease progression) scores were inversely related; the time-saving, four-stage scale of motor disability could predict the SPRS scores with a high statistical significance, and we encourage its use in HSP. Our study confirms SPG4 as the major cause of HSP. All SPG4 patients had a pure HSP phenotype, and the dominant inheritance was evident in the great majority of these subjects. SPG7 was the second genetic cause. Other genotypes were rarer (SPG10, SPG11, SPG17). CONCLUSION: Exact molecular diagnosis will allow a more accurate patient counseling and, hopefully, will lead to specific, targeted, therapeutic options for these chronic, still incurable diseases.

May "mitochondrial eve" and mitochondrial haplogroups play a role in neurodegeneration and Alzheimer's disease?

Mitochondria, the powerhouse of the cell, play a critical role in several metabolic processes and apoptotic pathways. Multiple evidences suggest that mitochondria may be crucial in ageing-related neurodegenerative diseases. Moreover, mitochondrial haplogroups have been linked to multiple area of medicine, from normal ageing to diseases, including neurodegeneration. Polymorphisms within the mitochondrial genome might lead to impaired energy generation and to increased amount of reactive oxygen species, having either susceptibility or protective role in several diseases. Here, we highlight the role of the mitochondrial haplogroups in the pathogenetic cascade leading to diseases, with special attention to Alzheimer's disease.

Cognitive outcome in adult women affected by congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

BACKGROUND: Some research suggests that girls with congenital adrenal hyperplasia (CAH), who are exposed to higher than normal levels of prenatal androgens, perform better on spatial tasks, worse on verbal tasks and have a greater incidence of left-handedness than unaffected controls, all of which suggests the development of a more male-typical cognitive pattern. However, research in all three areas has produced inconsistent findings. OBJECTIVES: To determine if prenatal androgen exposure has an organizing effect on female cognitive development and to what extent. METHODS: 24 women, 21-71 years, with either the salt-losing (SL) or simple virilizing (SV) forms of CAH due to 21-hydroxylase deficiency, and 18 controls, 21-73 years, who were unaffected female relatives or women with polycystic ovary syndrome, were assessed with IQ, handedness, executive function, verbal learning and memory, non-verbal learning and memory, perceptual speed, visuospatial processing and visuomotor ability measures. The battery included tests known to elicit sex differences and control measures. RESULTS: The findings did not support the hypothesis that women with CAH develop a more male-typical cognitive pattern. CONCLUSION: This study differs from others in the older age of its participants, grouping by SL/SV diagnosis and assessment of medical treatment and compliance as determined through hormone assays. Our findings provide additional support for the conclusion that, in adult women with CAH, previous prenatal androgen exposure does not enhance spatial abilities, impair verbal abilities nor alter hand preferences in a long-lasting way.

Spinal cord stimulation for axial low back pain: a prospective controlled trial comparing 16-contact insulated electrodes with 4-contact percutaneous electrodes.

Use of multicontact electrodes and programmable implanted pulse generators has increased the efficacy of spinal cord stimulation for pain. Some investigators find dual column electrodes advantageous for difficult-to-treat axial low back pain, but we have reported significantly improved measures with a single percutaneous midline electrode vs. dual percutaneous electrodes and even better results with an insulated, 1 × 4, midline electrode. In this study, 10 patients provided computerized, quantitative parameter measures for a temporary percutaneous 1 × 4 electrode and for a permanent insulated 2 × 8 electrode. Compared with the 2 × 8, the 1 × 4 resulted in marginally better patient-rated (109%, p = 0.06) and computer-calculated pain/paresthesia overlap (107%, p = 0.17); higher scaled amplitude to cover the low back (106%, NS); and significantly lower voltage (78%, p = 0.0004), increased extraneous coverage (141%, p = 0.0000), and improved symmetry (25%, p = 0.001). Thus, we observed no significant technical advantage for the insulated 2 × 8 in treating axial low back pain.

Spinal cord stimulation electrode design: a prospective, randomized, controlled trial comparing percutaneous with laminectomy electrodes: part II-clinical outcomes.

OBJECTIVE: Spinal cord stimulation, in use for more than 30 years, has evolved into an easily implemented technique involving percutaneous or laminectomy electrode placement. In a randomized comparison of four-contact percutaneous and four-contact insulated laminectomy electrodes placed at the same level in the dorsal, epidural midline, quantitative measures of stimulator performance revealed significant technical advantages for the laminectomy electrodes. Our prospective, randomized, controlled trial compares clinical results in these same patients. METHODS: Impartial third parties followed our series of 24 patients with failed back surgery syndrome to gather clinical outcome data. We defined "success" as at least 50% sustained relief of pain and patient satisfaction with the result of treatment. RESULTS: At a mean follow-up of 1.9 years, 10 of 12 patients receiving the laminectomy electrode and 5 of 12 patients receiving the percutaneous electrode reported a successful outcome (P < 0.05). Follow-up at a mean of 2.9 years showed that this result was maintained in 5 of 12 patients with the laminectomy electrode and 3 of 12 with the percutaneous electrode (not statistically significant). Many patients reported improvements in most activities of daily living, and loss of function was rare. In addition, 9 patients with laminectomy electrodes and 4 with percutaneous electrodes reducted or eliminated analgesic intake (P < 0.05), and 2 returned to work. No electrode migration was observed. CONCLUSION: Laminectomy electrode placement, although more invasive than percutaneous placement, yields significantly better clinical results in patients with failed back surgery syndrome at mean 1.9 years follow-up. In our small sample, however, the statistical significance of this advantage disappeared at mean 2.9 years follow-up.

Spinal cord stimulation for axial low back pain: a prospective, controlled trial comparing dual with single percutaneous electrodes.

STUDY DESIGN: A prospective, controlled, clinical trial comparing single and dual percutaneous electrodes in the treatment of axial low back pain from failed back surgery syndrome. OBJECTIVES: To clarify technical requirements and test the hypothesis that placing two linear arrays in parallel, thereby doubling the number of contacts, improves outcome. SUMMARY OF BACKGROUND DATA: Technical improvements have enhanced outcomes of spinal cord stimulation for chronic axial low back pain. Dual, parallel electrodes reportedly improve these outcomes. METHODS: Acting as their own controls, 20 patients who passed screening with single, 4-contact electrodes received permanent dual, 4-contact electrodes with 7- or 10-mm intercontact distances at the same vertebral level(s). We quantified and compared the technical and clinical results of the single and dual electrodes, adjusting stimulation parameters to specific psychophysical thresholds. RESULTS: Single electrodes provided significant (P < 0.01) advantages in patient- and computer-calculated ratings of pain coverage by paresthesias and in the scaled amplitude necessary to cover the low back, compared with dual 7-mm electrodes. Slight advantages without statistical significance were observed for the single over the dual 10-mm electrodes. Amplitude requirements were significantly lower for the single electrode than for either dual electrode. At long-term follow-up, 53% of patients met the criteria for clinical success. CONCLUSIONS: While we observed disadvantages for dual electrodes in treating axial low back pain, we achieved technical success with single or dual electrodes in most patients and maintained this success clinically with dual electrodes in 53%.