Multiple sclerosis susceptibility-associated SNPs do not influence disease severity measures in a cohort of Australian MS patients

Relevance of Multiple Sclerosis Severity Genotype in Predicting Disease Course: A Real-World Cohort

OBJECTIVE

Currently, 233 genetic loci are known to be associated with susceptibility to multiple sclerosis (MS). Two independent pivotal severity genome-wide association studies recently found the first genome-wide significant single-nucleotide variant (SNV; rs10191329A ) and several other suggestive loci associated with overall disability outcomes. It is now important to understand if these findings can influence individual patient management.

METHODS

We assessed whether these progression SNVs are associated with detailed clinical phenotypes in a well-characterized prospective cohort of 1,455 MS patients. We used logistic regression, survival analysis, and propensity score matching to predict relevant long-term clinical outcomes.

RESULTS

We were unable to detect any association between rs10191329A and a range of clinically relevant outcomes (eg, time to Expanded Disability Status Scale milestones, age-related MS severity score, anatomical localization at onset or during subsequent relapses, annualized relapse rate). In addition, an extremes of outcome case-control analysis using a propensity score matching for genotype detected no association between disease severity and rs10191329A . However, we were able to replicate the association of two suggestive SNVs (rs7289446G and rs868824C ) with the development of fixed disability, albeit with modest effect sizes, and the association of HLA-DRB1*1501 with age at onset.

INTERPRETATION

Identification of rs10191329A and other suggestive SNVs are of considerable importance in understanding pathophysiological processes associated with MS severity. However, it is unlikely that individual genotyping can currently be used in a clinical setting to guide disease management. This study shows the importance of independent replication of genome-wide association studies associated with disease progression in neurodegenerative disorders. ANN NEUROL 2024;95:459-470.

Ensemble machine learning identifies genetic loci associated with future worsening of disability in people with multiple sclerosis

Limited studies have been conducted to identify and validate multiple sclerosis (MS) genetic loci associated with disability progression. We aimed to identify MS genetic loci associated with worsening of disability over time, and to develop and validate ensemble genetic learning model(s) to identify people with MS (PwMS) at risk of future worsening. We examined associations of 208 previously established MS genetic loci with the risk of worsening of disability; we learned ensemble genetic decision rules and validated the predictions in an external dataset. We found 7 genetic loci (rs7731626: HR 0.92, P = 2.4 × 10^-5; rs12211604: HR 1.16, P = 3.2 × 10^-7; rs55858457: HR 0.93, P = 3.7 × 10^-7; rs10271373: HR 0.90, P = 1.1 × 10^-7; rs11256593: HR 1.13, P = 5.1 × 10^-57; rs12588969: HR = 1.10, P = 2.1 × 10^-10; rs1465697: HR 1.09, P = 1.7 × 10^-128) associated with risk worsening of disability; most of which were located near or tagged to 13 genomic regions enriched in peptide hormones and steroids biosynthesis pathways by positional and eQTL mapping. The derived ensembles produced a set of genetic decision rules that can be translated to provide additional prognostic values to existing clinical predictions, with the additional benefit of incorporating relevant genetic information into clinical decision making for PwMS. The present study extends our knowledge of MS progression genetics and provides the basis of future studies regarding the functional significance of the identified loci.

The Efficacy of Cannabis on Multiple Sclerosis-Related Symptoms

Multiple sclerosis (MS) is known as an autoimmune disease that damages the neurons in the central nervous system. MS is characterized by its most common symptoms of spasticity, muscle spasms, neuropathic pain, tremors, bladder dysfunction, dysarthria, and some intellectual problems, including memory disturbances. Several clinical studies have been conducted to investigate the effects of cannabis on the relief of these symptoms in MS patients. The efficacy of Cannabis sativa (C. Sativa) in the management of MS outcomes such as spasticity, pain, tremors, ataxia, bladder functions, sleep, quality of life, and adverse effects were assessed in this review. Most clinical studies showed the positive effects of cannabinoids with their different routes of administration, such as oromucosal spray and oral form, in reducing most MS symptoms. The oromucosal spray Nabiximols demonstrated an improvement in reducing MS spasticity, pain, and quality of life with a tolerated adverse effect. Oral cannabinoids are significantly effective for treating MS pain and spasticity, while the other symptoms indicate slight improvement and the evidence is quite inconsistent. Oromucosal spray and oral cannabis are mainly used for treating patients with MS and have positive effects on treating the most common symptoms of MS, such as pain and spasticity, whereas the other MS symptoms indicated slight improvement, for which further studies are needed.

Smoking, cardiovascular risk factors and LRP2 gene variation: Associations with disease severity, cognitive function and brain structure in primary progressive multiple sclerosis

BACKGROUND

Smoking, cardiovascular risk factors, and genetic factors can have adverse effects in MS.

OBJECTIVE

To determine if smoking after disease onset, cardiovascular risk factors, and genetic variants influence primary progressive MS (PPMS).

METHOD

In this cross-sectional study, smoking habits, Framingham Risk Score (FRS), genetic variants, including the low-density lipoprotein receptor-related protein 2 (LRP2) SNP rs12988804 and MRI were collected in 60 PPMS trial participants. Disability and cognition were assessed with the Age-Related Multiple Sclerosis Severity (ARMSS) score, the Progressive-Onset MS Multiple Sclerosis Severity Score, and the Brief International Cognitive Assessment for MS.

RESULTS

Smoking after PPMS onset was significantly associated with higher ARMSS (95% CI 0.8-2.4, p = 0.00016) statistically significant after Bonferroni correction. Lower magnetization transfer ratio in lesions was also significantly associated with smoking after onset of PPMS after correction (95% CI -0.9--4.4, p = 0.0035). Pack-years in people who smoked after onset was likewise significantly associated with higher ARMSS score (b = 0.06 95% CI 0.02-0.09, p = 0.0021) as well as lower Symbol Digit Modalities Test scores (b = -0.40; 95% CI -0.66--0.13, p = 0.0037), both statistically significant after Bonferroni correction. The LRP2 risk allele was associated with decreased performance on the California Verbal Learning Test 2 after correction (CC vs. CT+TT 95% CI -14.2--3.4, p = 0.0018).

CONCLUSION

If validated, these findings suggest that intervention regarding smoking may be beneficial in PPMS. If confirmed, assessment of the LRP2 gene variant may aid in the understanding of underlying pathological mechanisms in PPMS.

Class II HLA (DRB1, & DQB1) alleles and IL7R (rs6897932) variants and the risk for Multiple Sclerosis in Kerala, India

BACKGROUND

Different human leukocyte antigen (HLA) variants are known to modulate the risk of multiple sclerosis. The main objective of this study was to identify HLA-DRB1 and HLA-DQB1 alleles and Non -HLA gene IL7R (rs6897932) variants associated with MS.

METHODS

Patients attending the MS clinic, diagnosed with Multiple Sclerosis as per Mc Donald diagnostic criteria were the subjects in the study. The association of the highly polymorphic HLA-DRB1 and HLA-DQB1 loci was determined by high resolution tissue typing and the genotyping of the IL7R (rs6897932) variants was performed by Sanger sequencing in MS patients (n = 81) and healthy individuals (n = 82).

RESULTS

HLA-DRB1*15:01/15:02 alleles (OR = 3.65; p< 0.0001) and HLA-DQB1*06:02 (OR=4.19, p<0.0001) were found to be positively associated while HLA-DRB1*14:04:01 (OR = 0.21; p = 0.0009) was found to be negatively associated with MS. The most significant predisposing HLA haplotype was found to be DRB1*15:01-DQB1*06:02 (OR=5.69, p<0.0001). Univariate analysis of IL7R SNP (rs6897932) showed no significant association with MS in our population whereas analysis of HLA-DRB1 alleles and IL7R (rs6897932) genotypes showed significant association between the HLA-DRB1*15:01/15:02 and the IL7R (rs6897932) CC genotype (OR = 3.58, p = 0.0002).

CONCLUSION

HLA-DRB1*15:01, 15:02 and DQB1*06:02 are the predisposing alleles while HLA-DRB1*14:04 is the protective allele for MS in our population.

Identification of an iron-responsive subtype in two children diagnosed with relapsing-remitting multiple sclerosis using whole exome sequencing

BACKGROUND

Multiple sclerosis is a disorder related to demyelination of axons. Iron is an essential cofactor in myelin synthesis. Previously, we described two children (males of mixed ancestry) with relapsing-remitting multiple sclerosis (RRMS) where long-term remission was achieved by regular iron supplementation. A genetic defect in iron metabolism was postulated, suggesting that more advanced genetic studies could shed new light on disease pathophysiology related to iron.

METHODS

Whole exome sequencing (WES) was performed to identify causal pathways. Blood tests were performed over a 10 year period to monitor the long-term effect of a supplementation regimen. Clinical wellbeing was assessed quarterly by a pediatric neurologist and regular feedback was obtained from the schoolteachers.

RESULTS

WES revealed gene variants involved in iron absorption and transport, in the transmembrane protease, serine 6 (TMPRSS6) and transferrin (TF) genes; multiple genetic variants in CUBN, which encodes cubilin (a receptor involved in the absorption of vitamin B12 as well as the reabsorption of transferrin-bound iron and vitamin D in the kidneys); SLC25A37 (involved in iron transport into mitochondria) and CD163 (a scavenger receptor involved in hemorrhage resolution). Variants were also found in COQ3, involved with synthesis of Coenzyme Q10 in mitochondria. Neither of the children had the HLA-DRB1*1501 allele associated with increased genetic risk for MS, suggesting that the genetic contribution of iron-related genetic variants may be instrumental in childhood MS. In both children the RRMS has remained stable without activity over the last 10 years since initiation of nutritional supplementation and maintenance of normal iron levels, confirming the role of iron deficiency in disease pathogenesis in these patients.

CONCLUSION

Our findings highlight the potential value of WES to identify heritable risk factors that could affect the reabsorption of transferrin-bound iron in the kidneys causing sustained iron loss, together with inhibition of vitamin B12 absorption and vitamin D reabsorption (CUBN) and iron transport into mitochondria (SLC25A37) as the sole site of heme synthesis. This supports a model for RRMS in children with an apparent iron-deficient biochemical subtype of MS, with oligodendrocyte cell death and impaired myelination possibly caused by deficits of energy- and antioxidant capacity in mitochondria.

Identifying risk factors for cognitive issues in multiple sclerosis

INTRODUCTION

Cognitive impairment (CI) in Multiple Sclerosis (MS) has progressively regained clinical and research interest and is currently recognized as a debilitating and burdensome problem for these patients. Studying risk and protecting factors that may influence the development and course of CI is currently an area of increasing interest, due to the potential for preventive strategies. Areas covered: In this narrative review the authors briefly addressed the physiopathologic basis, assessment and management of CI in MS and then focused on identifying modifiable and not modifiable risk factors for CI in MS, providing an overview of the current knowledge in the field and indicating avenues for future research. Expert opinion: Improving our understanding of potentially modifiable environmental and lifestyle risk factors or protective factors for CI is important in order to prompt preventive strategies and orient patient counselling and clinical management. To this aim, we need to enhance the current level of evidence linking lifestyle factors to cognition and evaluate some factors that were only preliminary addressed in research. Moreover, we need to explore the role of each factor into the subject cognitive outcome, next to the possible interactions between different environmental factors as well as between environmental and genetic factors.

Genetics of Multiple Sclerosis: An Overview and New Directions

The contribution of genetic inheritance in multiple sclerosis was established early on. Although multiple sclerosis is not a Mendelian disease, its incidence and prevalence is higher in family members of affected individuals compared with the general population. Throughout the last decade, several small studies failed to identify any robust genetic associations besides the classic associations in the major histocompatibility complex region. During the past few years, genome-wide association studies (GWAS) have revolutionized the genetics of multiple sclerosis, uncovering more than 200 implicated genetic loci. Here, we describe these main findings and discuss the new avenues that these discoveries lay open.

BDNF Polymorphism: A Review of Its Diagnostic and Clinical Relevance in Neurodegenerative Disorders

Brain-derived neurotrophic factor (BDNF) has a unique role in the neuronal development, differentiation, and survival in the developing and adult nervous system. A common single-nucleotide polymorphism in the pro-region of the human BDNF gene, resulting in a valine to methionine substitution (Val66Met), has been associated with the susceptibility, incidence, and clinical features of several neurodegenerative disorders. Much research has been dedicated to evaluating the effects of polymorphism in the past decade, and functional effects of this genetic variation. A better understanding of how this naturally occurring polymorphism associates with or influences physiology, anatomy, and cognition in both healthy and diseased adults in neurodegenerative conditions will help understand neurochemical mechanisms and definable clinical outcomes in humans. Here we review the role and relevance of the BDNF Val66Met polymorphism in neurodegenerative diseases, with particular emphasis on glaucoma, multiple sclerosis (MS), Alzheimer’s disease (AD) and Parkinson’s disease (PD). Several controversies and unresolved issues, including small effect sizes, possible ethnicity, gender, and age effects of the BDNF Val66Met are also discussed with respect to future research.

Genome-wide association studies of multiple sclerosis

Large-scale genetic studies of multiple sclerosis have identified over 230 risk effects across the human genome, making it a prototypical common disease with complex genetic architecture. Here, after a brief historical background on the discovery and definition of the disease, we summarise the last fifteen years of genetic discoveries and map out the challenges that remain to translate these findings into an aetiological framework and actionable clinical understanding.

Genome-wide association study identifies distinct genetic contributions to prognosis and susceptibility in Crohn's disease

For most immune-mediated diseases, the main determinant of patient well-being is not the diagnosis itself but instead the course that the disease takes over time (prognosis). Prognosis may vary substantially between patients for reasons that are poorly understood. Familial studies support a genetic contribution to prognosis, but little evidence has been found for a proposed association between prognosis and the burden of susceptibility variants. To better characterize how genetic variation influences disease prognosis, we performed a within-cases genome-wide association study in two cohorts of patients with Crohn's disease. We identified four genome-wide significant loci, none of which showed any association with disease susceptibility. Conversely, the aggregated effect of all 170 disease susceptibility loci was not associated with disease prognosis. Together, these data suggest that the genetic contribution to prognosis in Crohn's disease is largely independent of the contribution to disease susceptibility and point to a biology of prognosis that could provide new therapeutic opportunities.

Feasibility study for remote assessment of cognitive function in multiple sclerosis

BACKGROUND

Cognitive impairment is common in multiple sclerosis (MS), and affects employment and quality of life. Large studies are needed to identify risk factors for cognitive decline. Currently, a MS-validated remote assessment for cognitive function does not exist. Studies to determine feasibility of large remote cognitive function investigations in MS have not been published.

OBJECTIVE

To determine whether MS patients would participate in remote cognitive studies. We utilized the Modified Telephone Interview for Cognitive Status (TICS-M), a previously validated phone assessment for cognitive function in healthy elderly populations to detect mild cognitive impairment. We identified factors that influenced participation rates. We investigated the relationship between MS risk factors and TICS-M score in cases, and score differences between cases and control individuals.

METHODS

The TICS-M was administered to MS cases and controls. Linear and logistic regression models were utilized.

RESULTS

11.5% of eligible study participants did not participate in cognitive testing. MS cases, females and individuals with lower educational status were more likely to refuse (p<0.001). Cases who did complete testing did not differ in terms of perceived cognitive deficit compared to cases that did participate. More severe disease, smoking, and being male were associated with a lower TICS-M score among cases (p<0.001). The TICS-M score was significantly lower in cases compared to controls (p=0.007).

CONCLUSIONS

Our results demonstrate convincingly that a remotely administered cognitive assessment is quite feasible for conducting large epidemiologic studies in MS, and lay the much needed foundation for future work that will utilize MS-validated cognitive measures.

Role of genetic susceptibility variants in predicting clinical course in multiple sclerosis: a cohort study

BACKGROUND

The genetic drivers of multiple sclerosis (MS) clinical course are essentially unknown with limited data arising from severity and clinical phenotype analyses in genome-wide association studies.

METHODS

Prospective cohort study of 127 first demyelinating events with genotype data, where 116 MS risk-associated single nucleotide polymorphisms (SNPs) were assessed as predictors of conversion to MS, relapse and annualised disability progression (Expanded Disability Status Scale, EDSS) up to 5-year review (ΔEDSS). Survival analysis was used to test for predictors of MS and relapse, and linear regression for disability progression. The top 7 SNPs predicting MS/relapse and disability progression were evaluated as a cumulative genetic risk score (CGRS).

RESULTS

We identified 2 non-human leucocyte antigen (HLA; rs12599600 and rs1021156) and 1 HLA (rs9266773) SNP predicting both MS and relapse risk. Additionally, 3 non-HLA SNPs predicted only conversion to MS; 1 HLA and 2 non-HLA SNPs predicted only relapse; and 7 non-HLA SNPs predicted ΔEDSS. The CGRS significantly predicted MS and relapse in a significant, dose-dependent manner: those having ≥5 risk genotypes had a 6-fold greater risk of converting to MS and relapse compared with those with ≤2. The CGRS for ΔEDSS was also significant: those carrying ≥6 risk genotypes progressed at 0.48 EDSS points per year faster compared with those with ≤2, and the CGRS model explained 32% of the variance in disability in this study cohort.

CONCLUSIONS

These data strongly suggest that MS genetic risk variants significantly influence MS clinical course and that this effect is polygenic.

A genetic basis for multiple sclerosis severity: Red herring or real?

Multiple Sclerosis (MS) is an autoimmune degenerative disease of the central nervous system, characterized by multifocal demyelination and neurodegeneration. The genetic architecture of MS is complex, where genetic risk has been attributed to over 100 polymorphic loci each with small odds ratios. MS is a highly heterogeneous disease with numerous clinical and paraclinical endophenotypes. To-date, no genetic variant has been associated with clinical outcome, however, evidence exists that MS outcomes, like risk, are to an extent also controlled by genetic variation. Here we summarise the current evidence for genetic determination of disease outcomes and make recommendations for future research directions.

Genetic Polymorphism of CYP27B1-1260 as Associated With Impaired Fasting Glucose in Patients With Chronic Hepatitis C Undergoing Antiviral Therapy

BACKGROUND

Recent studies have indicated that abnormal glucose levels and diabetes are negatively associated with the prognosis of patients with chronic hepatitis C virus (HCV) infection. The genetic polymorphism of the promoter region -1260 of a gene encoding the enzyme 1-alpha-hydroxylase (CYP27B1-1260) has been shown to have an impact on the signaling pathways involved in insulin secretion.

OBJECTIVES

The aim is to investigate the effect of CYP27B1-1260 polymorphism on the fasting plasma glucose (FPG) levels in patients with chronic HCV undergoing antiviral therapy.

PATIENTS AND METHODS

A total of 461 patients with chronic HCV infection and 300 volunteers without HCV infection were enrolled in an observational cohort study in the China-Japan Union hospital of Jilin University and the Second Hospital of Daqing, Changchun, Jilin Province. Both groups were further divided into normal and abnormal FPG subgroups. The frequencies of the three CYP27B1-1260 genotypes (AA, AC, and CC) were determined in each subgroup. FPG levels were monitored at baseline in HCV and control participants, and both during and after antiviral therapy in HCV infected patients. The frequency of each genotype was determined. Logistic regression analysis was performed to evaluate the risk factors associated with abnormal FPG levels in HCV infected patients undergoing antiviral therapy.

RESULTS

In HCV infected patients with abnormal FPG levels, the frequency of the genotype CC was significantly higher than that in patients with normal FPG levels (19% vs. 7%, P < 0.001). In contrast, in the control participants, the CC genotype was not significantly different between FPG groups. At baseline, the CC genotype was associate with four times more risk of IFG after adjusting for multiple variables (OR: 4.11; 95%CI: 1.98 - 8.52, P = 0.0001). During 24 weeks of anti-HCV treatment, 38 HCV participants developed newly-diagnosed impaired fasting glucose. The CC genotype markedly increased the risk for newly developed IFG (OR: 26.54; 95%CI: 7.80 - 90.32, P < 0.0001). Other risk factors included age and body mass index.

CONCLUSIONS

CYP27B1-1260 polymorphism is associated with abnormal glucose metabolism in HCV infected patients. HCV infected individuals with CYP27B1-1260 genotype CC appeared to have an increased risk of developing abnormal FPG levels.

Factors associated with onset, relapses or progression in multiple sclerosis: A systematic review

Multiple sclerosis (MS) is a chronic disease of the central nervous system with an unidentified etiology. We systematically reviewed the literature on the possible risk factors associated with MS disease onset, relapses and progression from 1960 to 2012 by accessing six databases and including relevant systematic reviews, meta-analyses, case-control or cohort studies. The focus was on identifying modifiable risk factors. Fifteen systematic reviews and 169 original articles were quality assessed and integrated into a descriptive review. Best evidence, which included one or more prospective studies, suggested that lower exposure to sunlight and/or lower serum vitamin D levels were associated with an increased risk of developing MS onset and subsequent relapses, but a similar quality of evidence was lacking for disease progression. Prospective studies indicated that cigarette smoking may increase the risk of MS as well as accelerate disease progression, but whether smoking altered the risk of a relapse was largely unknown. Infections were implicated in both risk of developing MS and relapses, but data for progression were lacking. Specifically, exposure to the Epstein-Barr virus, particularly if this manifested as infectious mononucleosis during adolescence, was associated with increased MS risk. Upper respiratory tract infections were most commonly associated with an increase in relapses. Relapse rates typically dropped during pregnancy, but there was no strong evidence to suggest that pregnancy itself altered the risk of MS or affected long-term progression. Emerging research with the greatest potential to impact public health was the suggestion that obesity during adolescence may increase the risk of MS; if confirmed, this would be of major significance.

Association of CD58 Polymorphism with Multiple Sclerosis and Response to Interferon ß Therapy in A Subset of Iranian Population

Objective

Multiple sclerosis (MS) is one of the leading neurodegenerative causes of physical disability world-wide. Genetic aberrations of autoimmunity pathway components have been demonstrated to significantly influence MS development. Cluster of Differentiation 58 (CD58) is pertained to a group of genes which had been assayed in several recent association studies. Given the significance of CD58 in modulation of T regulatory cells that control autoimmune responses, the present study was conducted to investigate the frequency of rs12044852 polymorphism and its effect on the outcome of interferon beta (IFN-β) therapy in a subset of Iranian MS patients.

Materials and Methods

Two hundred MS patients and equal number of healthy controls were recruited to be genotyped in an experimental case-control based study through polymerase chain reaction using specific sequence primers (PCR-SSP). Relapsing remitting multiple sclerosis (RRMS) patients administered IFN-β therapy were followed up with clinical visits every three months up to two years. The mean of multiple sclerosis severity score (MSSS) and expanded disability status scale (EDSS) were measured to monitor the change in severity of MS in response to IFN-β therapy. Pearson’s Chi-square and analysis of variance (ANOVA) tests were the main statistical methods used in this study.

Results

Strong association was found between the CC genotype and onset of MS (p=0.001, OR=2.22). However, there was no association between rs12044852 and various classifications and severity of MS. Pharmacogenetics-based analysis indicated that carriers of CC genotype had the highest MSSS score compared to others, implying a negative impact of rs12044852 on response to IFN-β therapy.

Conclusion

Taken together, our findings revealed the critical effect of rs12044852 polymorphism of CD58 on the progression of MS disease. This indicates that genotyping of MS patients may expedite achieving personalized medical management of MS patients.

Analysis of genes, pathways and networks involved in disease severity and age at onset in primary-progressive multiple sclerosis

Background:

The role of genetic factors in influencing the clinical expression of multiple sclerosis (MS) is unclear.

Objective:

The objective of this paper is to identify genes, pathways and networks implicated in age at onset (AAO) and severity, measured using the Multiple Sclerosis Severity Score (MSSS), of primary-progressive MS (PPMS).

Methods:

We conducted a genome-wide association study (GWAS) of 470 PPMS patients of Italian origin:. Allelic association of 296,589 SNPs with AAO and MSSS was calculated. Pathway and network analyses were also conducted using different tools.

Results:

No single association signal exceeded genome-wide significance in AAO and MSSS analyses. Nominally associated genes to AAO and MSSS were enriched in both traits for 10 pathways, including: “oxidative phosphorylation” (FDRAAO=9*10−4; FDRMSSS=3.0*10−2), “citrate (TCA) cycle” (FDRAAO=1.6*10−2; FDRMSSS=3.2*10−3), and “B cell receptor signaling” (FDRAAO=3.1*10−2; FDRMSSS=2.2*10−3). In addition, an enrichment of “chemokine signaling pathway” (FDR=9*10−4) for AAO and of “leukocyte transendothelial migration” (FDR=2.4*10−3) for MSSS trait was observed, among others. Network analysis revealed that p53 and CREB1 were central hubs for AAO and MSSS traits, respectively.

Conclusions:

Despite the fact that no major effect signals emerged in the present GWAS, our data suggest that genetic variants acting in the context of oxidative stress and immune dysfunction could modulate the onset and severity of PPMS.

Inverse correlation of genetic risk score with age at onset in bout-onset and progressive-onset multiple sclerosis

We correlated the weighted genetic risk score measured using 107 established susceptibility variants for multiple sclerosis (MS) with the age at onset in bout-onset (BOMS, n=906) and progressive-onset MS Italian patients (PrMS) (n=544). We observed an opposite relationship in the two disease courses: a higher weighted genetic risk score was associated with an earlier age at onset in BOMS (rho= -0.1; p=5 × 10(-3)) and a later age at onset in PrMS cases (rho=0.07; p=0.15) (p of difference of regression=1.4 × 10(-2)). These findings suggest that established MS risk variants anticipate the onset of the inflammatory phase, while they have no impact on, or even delay, the onset of the progressive phase.

Imaging phenotypes in multiple sclerosis

Multiple sclerosis (MS) is a common disease of the central nervous system, with various clinical symptoms and a heterogeneous disease course. MRI can depict focal and diffuse manifestations of the disease, and accurately measure progression over time. The precise pathogenesis of MS is unknown. Nevertheless, genetic influences have been found for susceptibility to MS in linkage and association studies. More recent genome-wide association studies have revealed other genes to be related to disease susceptibility and severity, explaining part of the variability in symptoms, radiological manifestations and disease course. Studies relating genetics and imaging in MS are discussed in this paper.

Investigation of gene-gene interactions between CD40 and CD40L in Polish multiple sclerosis patients

CD40-CD40L interaction is necessary for the activation of both humoral and cellular immune response and has been suggested to play a role in the pathogenesis of multiple sclerosis (MS). Therefore, we analyzed the combined influence of the CD40 and CD40L variants on MS susceptibility and progression on well-defined Polish population. Our investigation revealed that CT individuals in rs1883832 locus of CD40 possessed almost 1.5-fold higher risk for MS than CC individuals (OR = 1.44; 95%CI = 1.03-2.1; p = 0.032), while this risk for TT individuals was almost 2.5-fold higher (OR = 2.36; 95%CI = 1.19-4.78; p = 0.014). Moreover, for the first time, we observed the association of CD40 gene with MS development and progression. We observed that for the rs1883832CC individuals the age at diagnosis was on average 2 years lower than for the rs1883832CT and rs1883832TT individuals (CI95% = -3.69-(-0.29); p = 0.023). Additionally, we detected that individuals with TT and CT genotypes showed lower risk of developing secondary progressive course in comparison to those with CC genotype. For rs1883832TT individuals this risk was 4-fold lower (HR = 0.24; CI95% = 0.10-0.53; p = 0.00062). Despite the fact that CD40-CD40L pathway plays a key role in development of autoimmune diseases, we were not able to detect gene-gene interactions between CD40 and CD40L polymorphisms associated with multiple sclerosis.

Interferon beta treatment of multiple sclerosis increases serum interleukin-7

BACKGROUND

Interleukin-7 (IL-7) is a non-redundant cytokine for T-cell development and survival. The IL-7 signaling pathway has been genetically and functionally associated with several autoimmune diseases including multiple sclerosis (MS).

OBJECTIVE

The objective of this paper is to elucidate the effect of the widely used immunomodulatory MS therapy interferon beta (IFNβ) on IL-7 homeostasis.

METHODS

Swedish MS patients were screened for IL-7 concentration in serum and blood cell counts. IL-7 receptor alpha chain (IL-7Rα) expression was determined by semi-quantitative real-time polymerase chain reaction (PCR) and flow cytometry.

RESULTS

IFNβ treatment led to significantly increased serum IL-7 levels (mean: 17 pg/ml) compared with healthy controls (mean: 7.6 pg/ml) and natalizumab-treated patients (mean: 5.3 pg/ml). In vitro and in vivo, peripheral blood leukocytes showed decreased IL-7Rα expression and IL-7 consumption upon IFNβ exposure, suggesting that their IL-7 responsiveness is impaired during treatment.

CONCLUSIONS

MS patients undergoing IFNβ treatment have increased serum IL-7 levels and decreased IL-7 consumption. Given IL-7's important role in T-cell immunity, this relationship may be highly relevant for IFNβ's treatment efficacy.

Association between multiple sclerosis risk-associated SNPs and relapse and disability--a prospective cohort study

BACKGROUND

The modulating effects of the multiple sclerosis (MS) risk-associated single-nucleotide polymorphisms (SNPs) on MS clinical course are not well established.

OBJECTIVES

The objective of this paper is to investigate whether known MS risk-associated SNPs were associated with clinical course, and whether these SNPs modified the 25(OH)D-relapse association.

METHODS

Using a prospective cohort of 141 participants with relapsing-remitting MS and genotype data followed between 2002 and 2005, genotype-vitamin D interactions and the genetic predictors of relapse were assessed using survival analysis, and genetic predictors of 25(OH)D and disability progression were evaluated by multilevel mixed-effects linear regression.

RESULTS

While no SNP reached statistical significance after multiple testing, five SNPs were associated with relapse, with significant cumulative genotype risk effects and two demonstrated significant allele dose-response. Two SNPs altered the 25(OH)D-relapse association with significant allele dose-response. Five SNPs modified levels of 25(OH)D, with significant cumulative genotype 'risk' effect, and three demonstrated significant allele dose-response. We found no consistent evidence for an association between any SNPs and disability.

CONCLUSIONS

Our study provides evidence for an association between known MS risk-associated SNPs and relapse. Our findings indicate gene-environment interactions may be an important mechanism on MS clinical course, and provide support for the role of vitamin D in MS relapse.

Multiple sclerosis susceptibility loci do not alter clinical and MRI outcomes in clinically isolated syndrome

It has not yet been established whether genetic predictors of multiple sclerosis (MS) susceptibility also influence disease severity and accumulation of disability. Our aim was to evaluate associations between 16 previously validated genetic susceptibility markers and MS phenotype. Patients with clinically isolated syndrome verified by positive magnetic resonance imaging (MRI) and cerebrospinal fluid findings (n=179) were treated with interferon-β. Disability and volumetric MRI parameters were evaluated regularly for 2 years. Sixteen single-nucleotide polymorphisms (SNPs) previously validated as predictors of MS susceptibility in our cohort and their combined weighted genetic risk score (wGRS) were tested for associations with clinical (conversion to MS, relapses and disability) and MRI disease outcomes (whole brain, grey matter and white matter volumes, corpus callosum cross-sectional area, brain parenchymal fraction, T2 and T1 lesion volumes) 2 years from disease onset using mixed-effect models. We have found no associations between the tested SNPs and the clinical or MRI outcomes. Neither the combined wGRS predicted MS activity and progression over 2-year follow-up period. Power analyses confirmed 90% power to identify clinically relevant changes in all outcome variables. We conclude that the most important MS susceptibility loci do not determine MS phenotype and disease outcomes.

Single nucleotide polymorphisms in multiple sclerosis: disease susceptibility and treatment response biomarkers

Multiple sclerosis (MS) is a chronic inflammatory demyelinating and neurodegenerative disease of the central nervous system characterized by unpredictable and variable clinical course. Etiology of MS involves both genetic and environmental factors. New technologies identified genetic polymorphisms associated with MS susceptibility among which immunologically relevant genes are significantly overrepresented. Although individual genes contribute only a small part to MS susceptibility, they might be used as biomarkers, thus helping to identify accurate diagnosis, predict clinical disease course and response to therapy. This review focuses on recent progress in research on MS genetics with special emphasis on the possibility to use single nucleotide polymorphism of candidate genes as biomarkers of susceptibility to disease and response to therapy.

Single-nucleotide polymorphism at CYP27B1-1260, but not VDR Taq I, is possibly associated with persistent hepatitis B virus infection

BACKGROUND

Vitamin D, beyond its role in calcium and bone metabolism, exhibits immunomodulatory effects on innate and adaptive immune pathways and is suggestively related to liver diseases.

OBJECTIVE

This study investigated the association of single-nucleotide polymorphisms in genes involved in vitamin D functions with hepatitis B virus (HBV) infection.

METHODS

Five hundred Chinese Han subjects, including 274 chronic HBV patients, 68 HBV infection resolvers, and 158 healthy controls without HBV infection, were studied. The CYP27B1-1260 promoter and the VDR Taq I polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Although there was no difference between HBV patients and healthy controls, HBV patients and healthy controls had a higher frequency of the CYP27B1-1260 genotype CC (15.0% vs. 2.9%, p=0.004 and 13.3% vs. 2.9%, p=0.006, respectively) and allele C (38.3% vs. 25.7%, p=0.006 and 39.2% vs. 25.7%, p=0.006, respectively) compared with resolvers. The genotype and allele frequencies of the VDR Taq I polymorphism had no difference between patients, resolvers, and healthy controls.

CONCLUSION

These results suggest that the CYP27B1-1260 promoter polymorphism is possibly associated with the persistence, but not susceptibility to HBV infection in Chinese HBV patients, and that the VDR Taq I polymorphism is not suggested to be related to chronic HBV infection.

Genotype-phenotype correlation for non-HLA disease associated risk alleles in multiple sclerosis

BACKGROUND

Recent advances in MS genetics have led to the successful identification of a number of novel disease associated non-HLA genes. It is now becoming possible to begin to analyse the possible effects of these genes on aspects of disease phenotype where longitudinal clinical data is available.

OBJECTIVE

We examined phenotypic impact of 10 non-HLA disease associated single nucleotide polymorphisms (SNPs) in 1003 patients with MS followed for an average of 14.1 years.

METHODS

Association of SNPs with time to established disability milestones (Expanded Disability Status Scale (EDSS) 4.0, 6.0, 8.0), onset of secondary progression and cross-sectional aspects of early phenotype were tested using survival analysis.

RESULTS

No SNP was associated with systematic deflection in time to disability milestones, age at onset or time to secondary progression.

CONCLUSIONS

Genotypic information from non-HLA associated SNPs is unlikely to inform individual patient prognosis in the clinical setting although minor phenotypic effects operative at specific phases of disease cannot be excluded. This preliminary study provides a framework for future genotype-phenotype analysis in MS and will need to be replicated in independent patient cohorts.

Genome-wide association study of severity in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system with a strong genetic component. Several lines of evidence support a strong role for genetic factors influencing both disease susceptibility and clinical outcome in MS. Identification of genetic variants that distinguish particular disease subgroups and/or predict a severe clinical outcome is critical to further our understanding of disease mechanisms and guide development of effective therapeutic approaches. We studied 1470 MS cases and performed a genome-wide association study of more than 2.5 million single-nucleotide polymorphisms to identify loci influencing disease severity, measured using the MS severity score (MSSS), a measure of clinical disability. Of note, no single result achieved genome-wide significance. Furthermore, variants within previously confirmed MS susceptibility loci do not appear to influence severity. Although bioinformatic analyses highlight certain pathways that are over-represented in our results, we conclude that the genetic architecture of disease severity is likely polygenic and comprised of modest effects, similar to what has been described for MS susceptibility, to date. However, a role for major effects of rare variants cannot be excluded. Importantly, our results also show the MSSS, when considered as a binary or continuous phenotype variable is by comparison a stable outcome.

Risk factors for and management of cognitive dysfunction in multiple sclerosis

Cognitive impairment is common in multiple sclerosis (MS), especially when assessed by neuropsychological tests that emphasize mental processing speed, episodic memory, and some aspects of executive function. In this Review, we question why some MS patients develop severe impairment in cognitive abilities, while cognitive ability remains intact in others. We find that the heterogeneity in neuropsychological presentation among patients with MS reflects the influence of many factors, including genetics, sex, intelligence, disease course, comorbid neuropsychiatric illness, and health behaviors. Neuropsychological deficits are also robustly correlated with brain MRI metrics. Male patients with early evidence of cerebral gray matter atrophy are most prone to impairment, whereas high premorbid intelligence improves the neuropsychological prognosis. Routine evaluation of cognition is useful for helping patients to navigate problems related to activities of daily living and work disability and, if reliable methods are employed, cognitive decline can be detected and included among the many clinical signs of disease progression or treatment failure. Pharmacological treatments for neuropsychological impairment are on the horizon, although presently no firm medical indications exist for the condition.

Relevance of IL7R genotype and mRNA expression in Dutch patients with multiple sclerosis

Background: The interleukin 7 receptor (IL7R) has been recognized as a susceptibility gene for Multiple Sclerosis (MS). Analysis of rs6897932 (the most strongly MS-associated single nucleotide polymorphism (SNP)), showed effects of genotype on the relative expression of membrane-bound to total amount of IL7R mRNA.

Objective: We assessed the relevance of IL7R on MS phenotype (including clinical and magnetic resonance imaging (MRI) parameters) at DNA and mRNA level in Dutch patients with MS.

Methods: The genotype of rs6897932 was analyzed in 697 patients with MS and 174 healthy controls. The relevance of genotype and carriership of the C allele on MS phenotype (disease activity and severity, using clinical and MRI parameters) was assessed. In addition, relative gene expression of membrane-bound to total IL7R mRNA was analyzed with respect to disease phenotype in a subgroup of 95 patients with early relapsing MS.

Results: In particular, homozygosity for the risk allele is a risk factor for MS in our population (ORCC vs CT and TT = 1.65 (95% CI: 1.18–2.30), two-sided p = 0.004). However, no effect of genotype or the relative expression of membrane-bound IL7R (presence of exon 6–7) to total amount of IL7R mRNA (presence of exon 4–5) was found on MS phenotype.

Discussion: Homozygosity for the IL7R exon 6 rs6897932 C allele is associated with a higher risk for MS in our Dutch population. No effect was found of genotype or mRNA expression on disease phenotype.

Vitamin D and multiple sclerosis: what are the guidelines for a reliable clinical trial?

Evaluation of: Mowry EM, Krupp LB, Milazzo M et al. Vitamin D status is associated with relapse rate in pediatric-onset multiple sclerosis. Ann. Neurol. 67, 618-624 (2010). In 1960, Sir Donald Acheson suggested a link between multiple sclerosis and solar radiation. Some 50 years and numerous studies later, there is still no certainty about the role of UV or vitamin D, the sun-induced hormone, on the course of multiple sclerosis. In order to further clarify this issue, the article by Mowry et al. assesses the level of vitamin D in patients at the time of multiple sclerosis onset and correlates it with the number of subsequent clinical relapses. The conclusion is that every 10 ng/ml increase in the adjusted vitamin D level is associated with a 34% decrease in the rate of relapse. This result reinforces the rationale for a randomized double-blind placebo-controlled clinical trial. Several criteria for a well-designed trial are proposed.