Subcutaneous sodium valproate in palliative care: A systematic review

BACKGROUND

Seizures are an important palliative symptom, the management of which can be complicated by patients' capacity to swallow oral medications. In this setting, and the wish to avoid intravenous access, subcutaneous infusions may be employed. Options for antiseizure medications that can be provided subcutaneously may be limited. Subcutaneous sodium valproate may be an additional management strategy.

AIM

To evaluate the published experience of subcutaneous valproate use in palliative care, namely with respect to effectiveness and tolerability.

DESIGN

A systematic review was registered (PROSPERO CRD42023453427), conducted and reported according to PRISMA reporting guidelines.

DATA SOURCES

The databases PubMed, EMBASE and Scopus were searched for publications until August 11, 2023.

RESULTS

The searches returned 429 results, of which six fulfilled inclusion criteria. Case series were the most common study design, and most studies included <10 individuals who received subcutaneous sodium valproate. There were three studies that presented results on the utility of subcutaneous sodium valproate for seizure control, which described it to be an effective strategy. One study also described it as an effective treatment for neuropathic pain. The doses were often based on presumed 1:1 oral to subcutaneous conversion ratios. Only one study described a local site adverse reaction, which resolved with a change of administration site.

CONCLUSIONS

There are limited data on the use of subcutaneous sodium valproate in palliative care. However, palliative symptoms for which subcutaneous sodium valproate have been used successfully are seizures and neuropathic pain. The available data have described few adverse effects, supporting its use with an appropriate degree of caution.

A Genetic Risk Variant for Multiple Sclerosis Severity is Associated with Brain Atrophy

The minor allele of the genetic variant rs10191329 in the DYSF-ZNF638 locus is associated with unfavorable long-term clinical outcomes in multiple sclerosis patients. We investigated if rs10191329 is associated with brain atrophy measured by magnetic resonance imaging in a discovery cohort of 748 and a replication cohort of 360 people with relapsing multiple sclerosis. We observed an association with 28% more brain atrophy per rs10191329*A allele. Our results encourage stratification for rs10191329 in clinical trials. Unraveling the underlying mechanisms may enhance our understanding of pathophysiology and identify treatment targets. ANN NEUROL 2023;94:1080-1085.

A systematic review of the symptomatic management of Lhermitte's phenomenon

INTRODUCTION

Lhermitte's phenomenon (LP) is a transient shock-like sensation that radiates down the spine into the extremities, usually with neck flexion. The potential efficacy and tolerability of various symptomatic therapies in the management of LP have not been systematically reviewed previously.

METHOD

A systematic review was conducted using PubMed, EMBASE, and the Cochrane Library from inception to August 2022 for peer-reviewed articles describing the treatment of patients with Lhermitte's phenomenon. The review adheres to the PRISMA guidelines and was registered on PROSPERO.

RESULTS

This systematic review included sixty-six articles, which included 450 patients with LP. Treatment of the underlying cause varied by aetiology. Whilst LP is most commonly considered in the context of structural pathology of the cervical cord, medication-induced LP was a common theme in the literature. The most common cause of medication-induced LP was platinum-based chemotherapy agents such as cisplatin and oxaliplatin. In medication-induced LP, symptoms typically resolved with cessation of the causative agent. Non-pharmacological treatment options were associated with mild-moderate symptomatic improvement. The most commonly used agents to treat patients with LP were carbamazepine and gabapentin, which resulted in variable degrees of symptomatic benefit.

CONCLUSIONS

No randomised studies currently exist to support the use of symptomatic therapies to treat LP. Observational data suggest that some therapies may yield a symptomatic benefit in the management of LP. However, this systematic review identified a significant paucity of evidence in the literature, which suggests that further controlled studies are needed to investigate the optimal management of this common neurologic phenomenon.

Complement Factor I Gene Variant as a Treatable Cause of Recurrent Aseptic Neutrophilic Meningitis: A Case Report

Mutations in the complement factor I (CFI) gene have previously been identified as causes of recurrent CNS inflammation. We present a case of a 26-year-old man with 18 episodes of recurrent meningitis, who had a variant in CFI(c.859G>A,p.Gly287Arg) not previously associated with neurologic manifestations. He achieved remission with canakinumab, a human monoclonal antibody targeted at interleukin-1 beta.

Magnetic resonance-guided laser interstitial thermal therapy for drug-resistant epilepsy: A systematic review and individual participant data meta-analysis

Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has emerged as a popular minimally invasive alternative to open resective surgery for drug-resistant epilepsy (DRE). We sought to perform a systematic review and individual participant data meta-analysis to identify independent predictors of seizure outcome and complications following MRgLITT for DRE. Eleven databases were searched from January 1, 2010 to February 6, 2021 using the terms "MR-guided ablation therapy" and "epilepsy". Multivariable mixed-effects Cox and logistic regression identified predictors of time to seizure recurrence, seizure freedom, operative complications, and postoperative neurological deficits. From 8705 citations, 46 studies reporting on 450 MRgLITT DRE patients (mean age = 29.5 ± 18.1 years, 49.6% female) were included. Median postoperative seizure freedom and follow-up duration were 15.5 and 19.0 months, respectively. Overall, 240 (57.8%) of 415 patients (excluding palliative corpus callosotomy) were seizure-free at last follow-up. Generalized seizure semiology (hazard ratio [HR] = 1.78, p = .020) and nonlesional magnetic resonance imaging (MRI) findings (HR = 1.50, p = .032) independently predicted shorter time to seizure recurrence. Cerebral cavernous malformation (CCM; odds ratio [OR] = 7.97, p < .001) and mesial temporal sclerosis/atrophy (MTS/A; OR = 2.21, p = .011) were independently associated with greater odds of seizure freedom at last follow-up. Operative complications occurred in 28 (8.5%) of 330 patients and were independently associated with extratemporal ablations (OR = 5.40, p = .012) and nonlesional MRI studies (OR = 3.25, p = .017). Postoperative neurological deficits were observed in 53 (15.1%) of 352 patients and were independently predicted by hypothalamic hamartoma etiology (OR = 5.93, p = .006) and invasive electroencephalographic monitoring (OR = 4.83, p = .003). Overall, MRgLITT is particularly effective in treating patients with well-circumscribed lesional DRE, such as CCM and MTS/A, but less effective in nonlesional cases or lesional cases with a more diffuse epileptogenic network associated with generalized seizures. This study identifies independent predictors of seizure freedom and complications following MRgLITT that may help further guide patient selection.

Common genetic factors among autoimmune diseases

Autoimmune diseases display a high degree of comorbidity within individuals and families, suggesting shared risk factors. Over the past 15 years, genome-wide association studies have established the polygenic basis of these common conditions and revealed widespread sharing of genetic effects, indicative of a shared immunopathology. Despite ongoing challenges in determining the precise genes and molecular consequences of these risk variants, functional experiments and integration with multimodal genomic data are providing valuable insights into key immune cells and pathways driving these diseases, with potential therapeutic implications. Moreover, genetic studies of ancient populations are shedding light on the contribution of pathogen-driven selection pressures to the increased prevalence of autoimmune disease. This Review summarizes the current understanding of autoimmune disease genetics, including shared effects, mechanisms, and evolutionary origins.

A vital parameter? Systematic review of spirometry in evaluation for intensive care unit admission and intubation and ventilation for Guillain-Barré syndrome

BACKGROUND

Patients with Guillain-Barré syndrome (GBS) may require intensive care unit (ICU) admission for intubation and ventilation (I + V). The means to predict which patients will require I + V include spirometry measures. The aims of this study were to determine, for adult patients with GBS, how effectively different spirometry parameter thresholds predict the need for ICU admission and the requirement for I + V; and what effects these different parameter thresholds have on GBS patient outcomes.

METHOD

A systematic review was conducted of the databases PubMed, EMBASE, and Cochrane library in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The systematic review was registered prospectively on PROSPERO.

RESULTS

Initial searches returned 1011 results, of which 8 fulfilled inclusion criteria. All included studies were observational in nature. Multiple studies suggest that a vital capacity below 60% of predicted value on admission is associated with the need for eventual I + V. No included studies evaluated peak expiratory flow rate, or interventions with different thresholds for ICU or I + V.

CONCLUSIONS

There is a relationship between vital capacity and the need for I + V. However, there is limited evidence supporting specific thresholds for I + V. In addition to evaluating these factors, future research may evaluate the effect of different patient characteristics, including clinical presentation, weight, age, and respiratory comorbidities, on the effectiveness of spirometry parameters in the prediction of the need for I + V.

Single count breath test for the evaluation of respiratory function in Myasthenia Gravis: A systematic review

BACKGROUND

Myasthenia gravis (MG) can have a variety of respiratory presentations, ranging from mild symptoms through to respiratory failure. The evaluation of respiratory function in MG can be limited by accessibility to testing facilities, availability of medical equipment, and facial weakness. The single count breath test (SCBT) may be a useful adjunct in the evaluation of respiratory function in MG.

METHOD

A systematic review of the databases PubMed, EMBASE, and the Cochrane Library was conducted from inception to October 2022 in accordance with PRISMA guidelines and was registered on PROSPERO.

RESULTS

There were 6 studies that fulfilled the inclusion criteria. The described method of evaluating SCBT involves inhaling deeply, then counting at two counts per second, in English or Spanish, sitting upright, with normal vocal register, until another breath needs to be taken. The identified studies support that the SCBT has a moderate correlation with forced vital capacity. These results also support that SCBT can assist the identification of MG exacerbation, including via assessment over the telephone. The included studies support a threshold count of ≥ 25 as consistent with normal respiratory muscle function. Although further analysis is needed, the included studies describe the SCBT as a quick bedside tool that is inexpensive and well tolerated.

CONCLUSIONS

The results of this review support the clinical utility of the SCBT in assessing respiratory function in MG and describe the most current and effective methods of administration.

Polygenic risk score association with multiple sclerosis susceptibility and phenotype in Europeans

Polygenic inheritance plays a pivotal role in driving multiple sclerosis susceptibility, an inflammatory demyelinating disease of the CNS. We developed polygenic risk scores (PRS) of multiple sclerosis and assessed associations with both disease status and severity in cohorts of European descent. The largest genome-wide association dataset for multiple sclerosis to date (n = 41 505) was leveraged to generate PRS scores, serving as an informative susceptibility marker, tested in two independent datasets, UK Biobank [area under the curve (AUC) = 0.73, 95% confidence interval (CI): 0.72-0.74, P = 6.41 × 10-146] and Kaiser Permanente in Northern California (KPNC, AUC = 0.8, 95% CI: 0.76-0.82, P = 1.5 × 10-53). Individuals within the top 10% of PRS were at higher than 5-fold increased risk in UK Biobank (95% CI: 4.7-6, P = 2.8 × 10-45) and 15-fold higher risk in KPNC (95% CI: 10.4-24, P = 3.7 × 10-11), relative to the median decile. The cumulative absolute risk of developing multiple sclerosis from age 20 onwards was significantly higher in genetically predisposed individuals according to PRS. Furthermore, inclusion of PRS in clinical risk models increased the risk discrimination by 13% to 26% over models based only on conventional risk factors in UK Biobank and KPNC, respectively. Stratifying disease risk by gene sets representative of curated cellular signalling cascades, nominated promising genetic candidate programmes for functional characterization. These pathways include inflammatory signalling mediation, response to viral infection, oxidative damage, RNA polymerase transcription, and epigenetic regulation of gene expression to be among significant contributors to multiple sclerosis susceptibility. This study also indicates that PRS is a useful measure for estimating susceptibility within related individuals in multicase families. We show a significant association of genetic predisposition with thalamic atrophy within 10 years of disease progression in the UCSF-EPIC cohort (P < 0.001), consistent with a partial overlap between the genetics of susceptibility and end-organ tissue injury. Mendelian randomization analysis suggested an effect of multiple sclerosis susceptibility on thalamic volume, which was further indicated to be through horizontal pleiotropy rather than a causal effect. In summary, this study indicates important, replicable associations of PRS with enhanced risk assessment and radiographic outcomes of tissue injury, potentially informing targeted screening and prevention strategies.

The scalable precision medicine open knowledge engine (SPOKE): a massive knowledge graph of biomedical information

MOTIVATION

Knowledge graphs (KGs) are being adopted in industry, commerce and academia. Biomedical KG presents a challenge due to the complexity, size and heterogeneity of the underlying information.

RESULTS

In this work, we present the Scalable Precision Medicine Open Knowledge Engine (SPOKE), a biomedical KG connecting millions of concepts via semantically meaningful relationships. SPOKE contains 27 million nodes of 21 different types and 53 million edges of 55 types downloaded from 41 databases. The graph is built on the framework of 11 ontologies that maintain its structure, enable mappings and facilitate navigation. SPOKE is built weekly by python scripts which download each resource, check for integrity and completeness, and then create a 'parent table' of nodes and edges. Graph queries are translated by a REST API and users can submit searches directly via an API or a graphical user interface. Conclusions/Significance: SPOKE enables the integration of seemingly disparate information to support precision medicine efforts.

AVAILABILITY AND IMPLEMENTATION

The SPOKE neighborhood explorer is available at https://spoke.rbvi.ucsf.edu.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Dual ankyrinG and subpial autoantibodies in a man with well-controlled HIV infection with steroid-responsive meningoencephalitis: A case report

Neuroinvasive infection is the most common cause of meningoencephalitis in people living with human immunodeficiency virus (HIV), but autoimmune etiologies have been reported. We present the case of a 51-year-old man living with HIV infection with steroid-responsive meningoencephalitis whose comprehensive pathogen testing was non-diagnostic. Subsequent tissue-based immunofluorescence with acute-phase cerebrospinal fluid revealed anti-neural antibodies localizing to the axon initial segment (AIS), the node of Ranvier (NoR), and the subpial space. Phage display immunoprecipitation sequencing identified ankyrinG (AnkG) as the leading candidate autoantigen. A synthetic blocking peptide encoding the PhIP-Seq-identified AnkG epitope neutralized CSF IgG binding to the AIS and NoR, thereby confirming a monoepitopic AnkG antibody response. However, subpial immunostaining persisted, indicating the presence of additional autoantibodies. Review of archival tissue-based staining identified candidate AnkG autoantibodies in a 60-year-old woman with metastatic ovarian cancer and seizures that were subsequently validated by cell-based assay. AnkG antibodies were not detected by tissue-based assay and/or PhIP-Seq in control CSF (N = 39), HIV CSF (N = 79), or other suspected and confirmed neuroinflammatory CSF cases (N = 1,236). Therefore, AnkG autoantibodies in CSF are rare but extend the catalog of AIS and NoR autoantibodies associated with neurological autoimmunity.

The Eye as a Window to the Brain: Prominent Retinal Vasculopathy Points to Neuro-Behcet Diagnosis for an Undifferentiated Solitary Brain Lesion

Objective

To report a perplexing case of Behcet disease (BD) presenting as a focal parenchymal lesion that reached a diagnosis after noting a prominent retinal vasculopathy, highlighting the importance of ophthalmologic evaluation in undifferentiated CNS disease.

Background

BD can have variable systemic manifestations driven by a vasculitis, including oral or genital ulcers, pulmonary aneurysms, and uveitis. Neurologic involvement is present in less than 10% of patients, most commonly as a meningoencephalitis.

Design/Methods

We present the case of a woman who developed asymmetric sub-acute sensorineural hearing loss at age 31 followed by transient right facial weakness at age 40, and most recently presented with right facial numbness and arm weakness at age 47. Brain MRI revealed a left frontal enhancing lesion with associated T2/FLAIR hyperintensity extending from the periventricular to the juxtacortical area with a thin rim of a reduced diffusion. CSF and serum studies were negative for inflammation, infection and malignancy except for elevated ESR and CRP. Brain biopsy revealed non-specific gliosis. Persistent enhancement on MRI was noted over 3 months, with spontaneous clinical improvement. Patient endorsed insidious vision changes over recent years, and visual testing was performed.

Results

Dilated ophthalmic examination demonstrated striking peripheral attenuation and sclerosis of retinal vasculature, with evidence of nonperfusion and skip lesions on retinal fluorescein angiography (FA). Findings of occlusive retinal peripheral vasculopathy suggested an underlying vasculitis as the etiology of the brain lesion and prior deficits, raising the likelihood of BD. Patient was homozygous for HLA-B*51, further supporting this diagnosis even with lack of mucosal ulcers and negative history of pathergy.

Conclusions

Neurologic manifestations of BD can be diverse including retinal occlusive vasculopathy; ulcers are not universally present. Ophthalmologic examination, even when minimally symptomatic, can inform the diagnosis of CNS lesions. Patient was started on Prednisone, Infliximab and Methotrexate, achieving disease remission.

Gut microbiome of multiple sclerosis patients and paired household healthy controls reveal associations with disease risk and course

Changes in gut microbiota have been associated with several diseases. Here, the International Multiple Sclerosis Microbiome Study (iMSMS) studied the gut microbiome of 576 MS patients (36% untreated) and genetically unrelated household healthy controls (1,152 total subjects). We observed a significantly increased proportion of Akkermansia muciniphila, Ruthenibacterium lactatiformans, Hungatella hathewayi, and Eisenbergiella tayi and decreased Faecalibacterium prausnitzii and Blautia species. The phytate degradation pathway was over-represented in untreated MS, while pyruvate-producing carbohydrate metabolism pathways were significantly reduced. Microbiome composition, function, and derived metabolites also differed in response to disease-modifying treatments. The therapeutic activity of interferon-β may in part be associated with upregulation of short-chain fatty acid transporters. Distinct microbial networks were observed in untreated MS and healthy controls. These results strongly support specific gut microbiome associations with MS risk, course and progression, and functional changes in response to treatment.

FutureMS cohort profile: a Scottish multicentre inception cohort study of relapsing-remitting multiple sclerosis

PURPOSE

Multiple sclerosis (MS) is an immune-mediated, neuroinflammatory disease of the central nervous system and in industrialised countries is the most common cause of progressive neurological disability in working age persons. While treatable, there is substantial interindividual heterogeneity in disease activity and response to treatment. Currently, the ability to predict at diagnosis who will have a benign, intermediate or aggressive disease course is very limited. There is, therefore, a need for integrated predictive tools to inform individualised treatment decision making.

PARTICIPANTS

Established with the aim of addressing this need for individualised predictive tools, FutureMS is a nationally representative, prospective observational cohort study of 440 adults with a new diagnosis of relapsing-remitting MS living in Scotland at the time of diagnosis between May 2016 and March 2019.

FINDINGS TO DATE

The study aims to explore the pathobiology and determinants of disease heterogeneity in MS and combines detailed clinical phenotyping with imaging, genetic and biomarker metrics of disease activity and progression. Recruitment, baseline assessment and follow-up at year 1 is complete. Here, we describe the cohort design and present a profile of the participants at baseline and 1 year of follow-up.

FUTURE PLANS

A third follow-up wave for the cohort has recently begun at 5 years after first visit and a further wave of follow-up is funded for year 10. Longer-term follow-up is anticipated thereafter.

Correction: Vitamin D levels and risk of type 1 diabetes: A Mendelian randomization study

[This corrects the article DOI: 10.1371/journal.pmed.1003536.].

Childhood obesity and multiple sclerosis: A Mendelian randomization study

BACKGROUND

Higher childhood body mass index (BMI) has been associated with an increased risk of multiple sclerosis (MS).

OBJECTIVE

To evaluate whether childhood BMI has a causal influence on MS, and whether this putative effect is independent from early adult obesity and pubertal timing.

METHODS

We performed Mendelian randomization (MR) using summary genetic data on 14,802 MS cases and 26,703 controls. Large-scale genome-wide association studies provided estimates for BMI in childhood (n = 47,541) and adulthood (n = 322,154). In multivariable MR, we examined the direct effects of each timepoint and further adjusted for age at puberty. Findings were replicated using the UK Biobank (n = 453,169).

RESULTS

Higher genetically predicted childhood BMI was associated with increased odds of MS (odds ratio (OR) = 1.26/SD BMI increase, 95% confidence interval (CI): 1.07-1.50). However, there was little evidence of a direct effect after adjusting for adult BMI (OR = 1.03, 95% CI: 0.70-1.53). Conversely, the effect of adult BMI persisted independent of childhood BMI (OR = 1.43; 95% CI: 1.01-2.03). The addition of age at puberty did not alter the findings. UK Biobank analyses showed consistent results. Sensitivity analyses provided no evidence of pleiotropy.

CONCLUSION

Genetic evidence supports an association between childhood obesity and MS susceptibility, mediated by persistence of obesity into early adulthood but independent of pubertal timing.

The relative contributions of obesity, vitamin D, leptin, and adiponectin to multiple sclerosis risk: A Mendelian randomization mediation analysis

BACKGROUND

Obesity is associated with increased risk of multiple sclerosis (MS); however, the underlying mechanisms remain unclear.

OBJECTIVE

To determine the extent to which decreased vitamin D bioavailability and altered levels of adiponectin and leptin mediate the association between obesity and MS.

METHODS

We performed Mendelian randomization (MR) analyses to estimate the effects on MS of body mass index (BMI), 25-hydroxyvitamin D (25OHD), adiponectin, and leptin levels in a cohort of 14,802 MS cases and 26,703 controls. We then estimated the proportion of the effect of obesity on MS explained by these potential mediators.

RESULTS

Genetic predisposition to higher BMI was associated with increased MS risk (odds ratio (OR) = 1.33 per standard deviation (SD), 95% confidence interval (CI) = 1.09-1.63), while higher 25OHD levels reduced odds of MS (OR = 0.72 per SD, 95% CI = 0.60-0.87). In contrast, we observed no effect of adiponectin or leptin. In MR mediation analysis, 5.2% of the association between BMI and MS was attributed to obesity lowering 25OHD levels (95% CI = 0.3%-31.0%).

CONCLUSIONS

This study found that a minority of the increased risk of MS conferred by obesity is mediated by lowered vitamin D levels, while leptin and adiponectin had no effect. Consequently, vitamin D supplementation would only modestly reverse the effect of obesity on MS.

Mendelian randomization provides no evidence for a causal role in the bidirectional relationship between depression and multiple sclerosis

BACKGROUND

Major depressive disorder (MDD) is common in multiple sclerosis (MS) and its incidence rises before MS diagnosis. However, the causality and direction of this association remain unclear.

OBJECTIVE

The objective is to investigate the bidirectional relationship between MS and MDD using Mendelian randomization (MR).

METHODS

We selected genetic instruments associated with risk of MDD (n = 660,937 cases; 1,453,489 controls) and MS (n = 47,429 cases; 68,374 controls). Using two-sample MR, we examined putative causal effects in either direction, with sensitivity analyses to assess pleiotropy. Also, we adjusted for body mass index (BMI) in multivariable MR.

RESULTS

We found no effect of genetic liability to MDD on the odds of MS (OR = 1.07/doubling in odds, 95% CI = 0.90-1.28). Similarly, our findings did not support a causal effect of genetic liability to MS on MDD (OR = 1.00/doubling in odds, 95% CI = 0.99-1.01). Despite heterogeneity, sensitivity analyses indicated that bias from pleiotropy was unlikely. Conversely, genetic predisposition toward higher BMI increased the odds of MS (OR = 1.34/SD increase, 95% CI = 1.09-1.65) and MDD (OR = 1.08, 95% CI = 1.01-1.15).

CONCLUSION

This study does not support a causal association between MDD genetic liability and MS susceptibility, and vice versa. Genetic evidence suggesting commonality of obesity to both conditions may partly explain the increased incidence of depression pre-MS diagnosis.

Vitamin D levels and risk of type 1 diabetes: A Mendelian randomization study

BACKGROUND

Vitamin D deficiency has been associated with type 1 diabetes in observational studies, but evidence from randomized controlled trials (RCTs) is lacking. The aim of this study was to test whether genetically decreased vitamin D levels are causally associated with type 1 diabetes using Mendelian randomization (MR).

METHODS AND FINDINGS

For our two-sample MR study, we selected as instruments single nucleotide polymorphisms (SNPs) that are strongly associated with 25-hydroxyvitamin D (25OHD) levels in a large vitamin D genome-wide association study (GWAS) on 443,734 Europeans and obtained their corresponding effect estimates on type 1 diabetes risk from a large meta-analysis of 12 type 1 diabetes GWAS studies (Ntot = 24,063, 9,358 cases, and 15,705 controls). In addition to the main analysis using inverse variance weighted MR, we applied 3 additional methods to control for pleiotropy (MR-Egger, weighted median, and mode-based estimate) and compared the respective MR estimates. We also undertook sensitivity analyses excluding SNPs with potential pleiotropic effects. We identified 69 lead independent common SNPs to be genome-wide significant for 25OHD, explaining 3.1% of the variance in 25OHD levels. MR analyses suggested that a 1 standard deviation (SD) decrease in standardized natural log-transformed 25OHD (corresponding to a 29-nmol/l change in 25OHD levels in vitamin D-insufficient individuals) was not associated with an increase in type 1 diabetes risk (inverse-variance weighted (IVW) MR odds ratio (OR) = 1.09, 95% CI: 0.86 to 1.40, p = 0.48). We obtained similar results using the 3 pleiotropy robust MR methods and in sensitivity analyses excluding SNPs associated with serum lipid levels, body composition, blood traits, and type 2 diabetes. Our findings indicate that decreased vitamin D levels did not have a substantial impact on risk of type 1 diabetes in the populations studied. Study limitations include an inability to exclude the existence of smaller associations and a lack of evidence from non-European populations.

CONCLUSIONS

Our findings suggest that 25OHD levels are unlikely to have a large effect on risk of type 1 diabetes, but larger MR studies or RCTs are needed to investigate small effects.

Mendelian randomization study shows no causal effects of serum urate levels on the risk of MS

Objective

To examine whether lifelong genetically increased serum urate levels, a potent antioxidant, contribute to MS susceptibility using Mendelian randomization (MR).

Methods

This 2-sample MR study included 25 independent genetic variants strongly associated with serum urate levels in a genome-wide association study meta-analysis of 140,949 individuals. Effects on the risk of MS were assessed with summary statistics from 3 large-scale MS genetic data sets totaling 61,667 MS cases and 86,806 controls from the International MS Genetic Consortium. Multiple sensitivity analyses were performed to evaluate the assumptions of MR and remove potentially pleiotropic variants.

Results

Using inverse-variance weighted MR, we found no evidence for a causal effect of serum urate level on the risk of MS in any of the cohorts (MS1: OR 0.99 per each mg/dL unit increase in urate, 95% CI 0.89–1.08, p = 0.76; MS2: OR = 0.99, 95% CI 0.89–1.11, p = 0.90; MS3: OR = 1.00, 95% CI 0.98–1.2, p = 0.91). Pleiotropy robust MR methods yielded consistent estimates.

Conclusion

This MR study does not support a clinically relevant causal effect of serum urate levels on the risk of MS.

Little evidence for an effect of smoking on multiple sclerosis risk: A Mendelian Randomization study

The causes of multiple sclerosis (MS) remain unknown. Smoking has been associated with MS in observational studies and is often thought of as an environmental risk factor. We used two-sample Mendelian randomization (MR) to examine whether this association is causal using genetic variants identified in genome-wide association studies (GWASs) as associated with smoking. We assessed both smoking initiation and lifetime smoking behaviour (which captures smoking duration, heaviness, and cessation). There was very limited evidence for a meaningful effect of smoking on MS susceptibility as measured using summary statistics from the International Multiple Sclerosis Genetics Consortium (IMSGC) meta-analysis, including 14,802 cases and 26,703 controls. There was no clear evidence for an effect of smoking on the risk of developing MS (smoking initiation: odds ratio [OR] 1.03, 95% confidence interval [CI] 0.92-1.61; lifetime smoking: OR 1.10, 95% CI 0.87-1.40). These findings suggest that smoking does not have a detrimental consequence on MS susceptibility. Further work is needed to determine the causal effect of smoking on MS progression.

Genetic Determinants of Antibody-Mediated Immune Responses to Infectious Diseases Agents: A Genome-Wide and HLA Association Study

BACKGROUND

Infectious diseases are causally related to a large array of noncommunicable diseases (NCDs). Identifying genetic determinants of infections and antibody-mediated immune responses may shed light on this relationship and provide therapeutic targets for drug and vaccine development.

METHODS

We used the UK biobank cohort of up to 10 000 serological measurements of infectious diseases and genome-wide genotyping. We used data on 13 pathogens to define 46 phenotypes: 15 seropositivity case-control phenotypes and 31 quantitative antibody measurement phenotypes. For each of these, we performed genome-wide association studies (GWAS) using the fastGWA linear mixed model package and human leukocyte antigen (HLA) classical allele and amino acid residue associations analyses using Lasso regression for variable selection.

RESULTS

We included a total of 8735 individuals for case-control phenotypes, and an average (range) of 4286 (276-8555) samples per quantitative analysis. Fourteen of the GWAS yielded a genome-wide significant (P < 5 ×10-8) locus at the major histocompatibility complex (MHC) on chromosome 6. Outside the MHC, we found a total of 60 loci, multiple associated with Epstein-Barr virus (EBV)-related NCDs (eg, RASA3, MED12L, and IRF4). FUT2 was also identified as an important gene for polyomaviridae. HLA analysis highlighted the importance of DRB1*09:01, DQB1*02:01, DQA1*01:02, and DQA1*03:01 in EBV serologies and of DRB1*15:01 in polyomaviridae.

CONCLUSIONS

We have identified multiple genetic variants associated with antibody immune response to 13 infections, many of which are biologically plausible therapeutic or vaccine targets. This may help prioritize future research and drug development.

Elevated body mass index is associated with an increased risk of infectious disease admissions and mortality: a mendelian randomization study

OBJECTIVE

The effect of body mass index (BMI) on the risk of infectious diseases admissions and mortality is unclear and is difficult to study given the risks of confounding variables.

METHODS

We used genome-wide association studies (GWASs) with mendelian randomization (MR) to obtain causal inference of BMI on the following infectious diseases outcomes: hospital admissions for pneumonia, sepsis, urinary tract infections, skin and soft tissue infections (SSTIs) or all-cause infections. For patients with pneumonia and sepsis, we also analysed their 28-day and 90-day mortalities. The UK Biobank (UKB) cohort (n > 500 000) provided data for GWASs on infectious diseases. The GIANT consortium (n = 681 265) GWAS was used to identify single-nucleotide polymorphisms (SNPs) associated with BMI.

RESULTS

Genetically increased BMI, by one standard deviation, was associated with higher rates of admission due to all infectious disease. The effect was most important for SSTIs (OR: 1.11, 95%CI: 1.09, 1.12). Increasing BMI by one standard deviation was associated with higher pneumonia mortality, especially at 28 days (OR: 1.03, 95%CI: 1.01, 1.05). BMI was not clearly associated with sepsis mortality, although interpretation of the results was limited by a small sample size. There were consistent findings in sensitivity analysis performed by removing highly pleiotropic SNPs and multivariate MR including type-2 diabetes mellitus, estimated glomerular filtration rate, high-density lipoprotein, educational attainment, and a history of smoking.

CONCLUSIONS

Increased BMI was associated with increased risk of admission for infectious disease and mortality. While the pathophysiology behind this phenomenon remains unknown, increasing BMI may influence immune dysregulation.

Genome-wide Association Study for Vitamin D Levels Reveals 69 Independent Loci

We aimed to increase our understanding of the genetic determinants of vitamin D levels by undertaking a large-scale genome-wide association study (GWAS) of serum 25 hydroxyvitamin D (25OHD). To do so, we used imputed genotypes from 401,460 white British UK Biobank participants with available 25OHD levels, retaining single-nucleotide polymorphisms (SNPs) with minor allele frequency (MAF) > 0.1% and imputation quality score > 0.3. We performed a linear mixed model GWAS on standardized log-transformed 25OHD, adjusting for age, sex, season of measurement, and vitamin D supplementation. These results were combined with those from a previous GWAS including 42,274 Europeans. In silico functional follow-up of the GWAS results was undertaken to identify enrichment in gene sets, pathways, and expression in tissues, and to investigate the partitioned heritability of 25OHD and its shared heritability with other traits. Using this approach, the SNP heritability of 25OHD was estimated to 16.1%. 138 conditionally independent SNPs were detected (p value < 6.6 × 10-9) among which 53 had MAF < 5%. Single variant association signals mapped to 69 distinct loci, among which 63 were previously unreported. We identified enrichment in hepatic and lipid metabolism gene pathways and enriched expression of the 25OHD genes in liver, skin, and gastrointestinal tissues. We observed partially shared heritability between 25OHD and socio-economic traits, a feature which may be mediated through time spent outdoors. Therefore, through a large 25OHD GWAS, we identified 63 loci that underline the contribution of genes outside the vitamin D canonical metabolic pathway to the genetic architecture of 25OHD.

Mendelian randomization in multiple sclerosis: A causal role for vitamin D and obesity?

The etiology of multiple sclerosis (MS) involves a complex interplay of genetic and environmental factors. Epidemiologic studies have furthered our understanding of these risk factors but remain limited by residual confounding and potential for reverse causation, particularly in MS where time of disease onset is not known. Mendelian randomization (MR) uses genetic variants to study the causal effect of modifiable exposures on an outcome. This method avoids some of the limitations of classical epidemiology and can strengthen causal inference. Here, we introduce the basic concepts of MR and review its contributions to the field of MS. Indeed, several studies using MR have now provided support for a causal role for low vitamin D level and obesity in the development of MS.

Effect of age at puberty on risk of multiple sclerosis: A mendelian randomization study

OBJECTIVE

To investigate the potential for a causal effect of age at puberty on multiple sclerosis (MS) susceptibility using a mendelian randomization (MR) approach.

METHODS

We used 372 genetic variants strongly associated with age at menarche in a genome-wide association study (GWAS) involving 329,245 women. The genetic architecture of pubertal timing across both sexes is highly correlated (genetic correlation [r _g] = 0.75, p = 1.2 × 10^-79), allowing these variants to provide reliable insight into pubertal timing in males as well. The effect of pubertal timing on risk of MS was measured with summary statistics from a GWAS of 14,802 cases with MS and 26,703 controls from the International Multiple Sclerosis Genetics Consortium. Multivariable MR controlling for effects of body mass index (BMI) using genetic data from additional consortia investigated whether pubertal effects on MS were dependent on weight status.

RESULTS

A 1-year increase in genetically predicted age at puberty decreased odds of MS by 8% (odds ratio [OR] 0.92, 95% confidence interval [CI] 0.86-0.99, p = 0.03). However, multivariable MR analysis showed that after accounting for effects on adult BMI, the association of age at puberty with MS susceptibility attenuated (OR 0.96, 95% CI 0.88-1.04, p = 0.36). Similar results were obtained when childhood BMI was incorporated. Sensitivity analyses provided no evidence of major bias from genetic pleiotropy.

CONCLUSIONS

We found support for an association between higher age at puberty and decreased risk of MS with a magnitude comparable to that reported in observational studies. This effect appears to be largely mediated by the strong association between age at puberty and obesity. A large causal effect of pubertal timing independent of BMI is unlikely.

Secondary stroke prevention services in Canada: a cross-sectional survey and geospatial analysis of resources, capacity and geographic access

BACKGROUND

Rapid assessment and management of transient ischemic attacks and nondisabling strokes by specialized stroke prevention services reduces the risk of recurrent stroke and improves outcomes. In Canada, with its vast geography and with 16.8% of the population living in rural areas, access to these services is challenging, and considerable variation in access to care exists. The purpose of this multiphase study was to identify sites across Canada providing stroke prevention services, evaluate resource capacity and determine geographic access for Canadians.

METHODS

We developed a Stroke Prevention Services Resource Inventory that contained 22 questions on the organization and delivery of stroke prevention services and quality monitoring. The inventory ran from November 2015 to January 2016 and was administered online. We conducted a geospatial analysis to estimate access by drive times. Considerations were made for hours of operation and access within and across provincial borders.

RESULTS

A total of 123 stroke prevention sites were identified, of which 119 (96.7%) completed the inventory. Most (95) are designated stroke prevention or rapid assessment clinics. Of the 119 sites, 68 operate full time, and 39 operate less than 2.5 days per week. A total of 87.3% of the Canadian population has access to a stroke prevention service within a 1-hour drive; however, only 69.2% has access to a service that operates 5-7 days a week. Allowing provincial border crossing improves access (< 6-h drive) for those who are beyond a 6-hour drive within their home province (3.4%).

INTERPRETATION

Most Canadians have reasonable geographic access to stroke prevention services. Allowing patients to cross borders improves the existing access for many, particularly some remote communities along the Ontario-Quebec and British Columbia-Alberta borders.

Precuneal epilepsy: Clinical features and surgical outcome

OBJECTIVE

The precuneus is a complex and highly connected structure located in the medial portion of the superior parietal lobule. The clinical presentation of precuneal epilepsy is poorly characterized, mostly because these patients have seldom been distinguished from those with other types of parietal lobe epilepsy. The present study aims to improve the understanding of precuneal epilepsy by detailing its clinical features and surgical outcomes.

METHODS

Six previously unreported cases of drug-resistant precuneal epilepsy investigated between 2002 and 2014 were retrospectively studied. Seizure focus was confirmed by presence of a lesion, intracranial monitoring, or post-operative seizure control when applicable.

RESULTS

Seizures arising from the precuneus have heterogeneous presentations, including body movement sensation, visual auras, eye movements, vestibular manifestations, and complex motor behaviors. Two patients with an anterior precuneus lesion described body movement sensations whereas two others with a posterior precuneus lesion experienced visual symptoms. Two of the five patients who underwent epilepsy surgery achieved good seizure control (Engel IA). One patient underwent gamma knife surgery with an Engel IV outcome. Surgical complications included contralateral visual field impairment, limb hypoesthesia and hemispatial neglect. One patient developed late-onset epilepsia partialis continua from a Rolandic subdural grid-related contusion.

SIGNIFICANCE

In absence of a clear precuneal epileptogenic lesion, recognition of a precuneal focus is challenging. Magnetoencephalography may sometimes localize the generator but invasive EEG remains in well-selected cases necessary to identify the seizure focus. Surgical failures may be explained by the widespread connectivity of the precuneus with distant and adjacent structures. Different ictal manifestations of precuneal epilepsy in this series provide a clinical correlate to the described functional subdivisions of the precuneus.

Association of postoperative furosemide use with a reduced blood transfusion rate in sagittal craniosynostosis surgery

OBJECT A major challenge in sagittal craniosynostosis surgery is the high transfusion rate (50%-100%) related to blood loss in small pediatric patients. Several approaches have been proposed to prevent packed red blood cell (PRBC) transfusion, including endoscopic surgery, erythropoietin ortranexamic acid administration, and preoperative hemodilution. The authors hypothesized that a significant proportion of postoperative anemia observed in pediatric patients is actually dilutional. Consequently, since 2005, at CHU Sainte-Justine, furosemide has been administered to correct the volemic status and prevent PRBC transfusion. The purpose of this study was to evaluate the impact of postoperative furosemide administration on PRBC transfusion rates. METHODS This was a retrospective study of 96 consecutive patients with sagittal synostosis who underwent surgery at CHU Sainte-Justine between January 2000 and May 2012. The mean age at surgery was 4.9 ± 1.5 months (range 2.8-8.7 months). Patients who had surgery before 2005 constituted the control group. Those who had surgery in 2005 or 2006 were considered part of an implementation phase because furosemide administration was not routine. Patients who had surgery after 2006 were part of the experimental (or furosemide) group. Transfusion rates among the 3 groups were compared. The impact of furosemide administration on transfusion requirement was also measured while accounting for other variables of interest in a multiple logistic regression model. RESULTS The total transfusion rate was significantly reduced in the furosemide group compared with the control group (31.3% vs 62.5%, respectively; p = 0.009), mirroring the decrease in the postoperative transfusion rate between the groups (18.3% vs 50.0%, respectively; p = 0.003). The postoperative transfusion threshold remained similar throughout the study (mean hemoglobin 56.0 g/dl vs 60.9 g/dl for control and furosemide groups, respectively; p = 0.085). The proportion of nontransfused patients with recorded hemoglobin below 70 g/dl did not differ between the control and furosemide groups (41.7% vs 28.6%, respectively; p = 0.489). Surgical procedure, preoperative hemoglobin level, estimated blood loss, and furosemide administration significantly affected the risk of receiving a postoperative PRBC transfusion. When these variables were analyzed in a multiple logistic regression model, furosemide administration remained strongly associated with a reduced risk of being exposed to a blood transfusion (OR 0.196, p = 0.005). There were no complications related to furosemide administration. CONCLUSIONS A significant part of the postoperative anemia observed in patients who underwent sagittal craniosynostosis surgery was due to hypervolemic hemodilution. Correction of the volemic status with furosemide administration significantly reduces postoperative PRBC transfusion requirements in these patients.

Global sagittal alignment and health-related quality of life in lumbosacral spondylolisthesis

PURPOSE

Global sagittal alignment is considered as an important aspect in the management of spinal disorders, but the evidence establishing its clinical impact in lumbosacral spondylolisthesis is still poor. This study evaluated the impact of global sagittal alignment on the health-related quality of life (HRQOL) of patients with spondylolisthesis.

METHODS

A retrospective study of 149 consecutive unoperated children and adolescents presenting with lumbosacral spondylolisthesis (117 low-grade and 32 high-grade) was performed. Two global sagittal alignment parameters were measured on standing lateral radiographs: spinal tilt (ST) and C7 plumbline deviation (C7P deviation). All patients completed the SRS-22 questionnaire to assess HRQOL. Pearson's correlations were calculated between parameters of global sagittal alignment and HRQOL. Multiple regression analyses were also undertaken to account for slip percentage and lumbosacral kyphosis (LSK).

RESULTS

Both global sagittal alignment parameters were correlated with the SRS-22 total score. When analyzed separately, the correlation was absent in patients with a low-grade slip but remained significant for patients with a high-grade slip (r = 0.35 for ST; r = -0.35 for C7P deviation). The relation was strengthened in high-grade spondylolisthesis when considering only patients with a C7P in front of the posterior corner of upper sacral endplate (r = 0.48 for ST; r = -0.48 for C7P deviation) and was also positive for the SRS-22 pain and appearance domains. For these last patients, the relationship with global sagittal alignment remained significant in the multiple regression analysis. HRQOL was particularly worse for high-grade patients with a C7P in front of the hip axis.

CONCLUSIONS

In high-grade spondylolisthesis, an increasing positive sagittal alignment was related to a poorer SRS-22 total score, especially when the C7P is in front of the hip axis. Global sagittal alignment should particularly be assessed in patients with high-grade spondylolisthesis.