The natural history of multiple sclerosis: a geographically based study: 8: familial multiple sclerosis

Familial vs sporadic multiple sclerosis in the Israeli population: Differences in ethnicity distribution and disease progression, with anticipation in successive generations

BACKGROUND

Multiple Sclerosis (MS) may cluster in families, an entity known as familial MS (FMS), possibly due to aggregation of genetic and environmental factors. Though previous studies have characterized FMS in different populations, no study to the best of our knowledge has yet characterized FMS in the unique Israeli population, which is comprised of relatively endogamous ethnicities. Our goal in this study was to compare demographic and clinical characteristics between FMS and sporadic MS (SMS), and to search for intra-familial patterns.

METHODS

In a retrospective study of 101 FMS patients and 508 SMS patients, ethnicity and sex distribution was assessed. Clinical aspects were compared between 172 paired FMS and SMS patients, matched for sex, age and ethnicity, and between generations of the FMS cohort.

RESULTS

Females comprised 75.3 % of FMS and 67.5 % of SMS patients (p = 0.1). Ethnic distribution was significantly different between FMS and SMS (p = 0.014), with the former comprising a higher proportion of Christian-Arabs (15.4% vs. 5.1 %, p = 0.004) and lower proportion of Jews (60% vs. 74.2 %, p = 0.016). Age at disease onset or diagnosis, frequency of positive Oligoclonal bands and comorbidity of other autoimmune/inflammatory disease or chronic diseases was comparable between FMS and SMS, yet motor symptoms at onset were more prevalent in FMS (34% vs. 20 %, p = 0.02). Annualized relapse rates throughout 10 years from onset were comparable. Among FMS, mean Expanded-Disability-Status-Scale (EDSS) and slope of deterioration in EDSS over 20 years from diagnosis were higher (p = 0.0004 and p = 0.023, respectively), time to EDSS ≥ 3 was shorter (7.1 vs. 12.1 years, HR 1.6, p = 0.036) and MS-Severity-Score (MSSS) was higher (3.84 vs. 2.95, p = 0.04), compared to SMS. Following adjustment for smoking, which tended to be higher among FMS patients (P = 0.06), mean EDSS and slope of deterioration in EDSS over 20 years remained significantly higher (p = 0.0006 and p = 0.025, respectively) in FMS, time to EDSS ≥ 3 tended to be higher (HR 1.5, p = 0.06), while MSSS was comparable. An inter-generational analysis of the total FMS cohort, as well as an intra-familial analysis, both adjusted for year of diagnosis, revealed significantly earlier age of onset (p < 0.0001 and p < 0.0001) and diagnosis (p = 0.001 and p < 0.0001) in the younger compared to the older generations, respectively.

CONCLUSION

In this Israeli cohort, the proportions of specific ethnicities differ between FMS and SMS, indicating that FMS has a population-specific prevalence pattern, and that further investigation for susceptibility genes is warranted. Disease progression is faster in FMS patients and anticipation is observed in families with multiple cases of MS. Closer surveillance and application of a pro-active induction or early highly-effective therapeutic strategy for FMS patients should be considered, to reduce high disease activity and fast disability progression.

Recent advances in the treatment of primary and secondary progressive Multiple Sclerosis

BACKGROUND

The article highlights upcoming potential treatments, which target different phases of inflammation and offer remyelinating strategies as well as direct and indirect neuroprotective and oligodendrocyte protective effects, providing a hopeful outlook for patients with primary and secondary progressive multiple sclerosis (PPMS and SPMS).

OBJECTIVES

The review aims to identify potential treatments and ongoing clinical trials for PPMS and SPMS, and compare their mechanisms of action, efficacy, and side effects with current treatments.

METHODS

We reviewed ongoing clinical trials for PPMS and SPMS on the NIH website, as well as articles from PubMed, Embase, and clinicaltrails.gov since 2010.

RESULTS

BTKIs like, tolebrutinib, and fenebrutinib are being explored as potential PMS treatments. Vidofludimus calcium, an orally available treatment, has shown a reduction of active and new MRI lesions. Other treatments like simvastatin, N-acetylcysteine (NAC), and alpha-lipoic acid are being explored for their antioxidant properties. AHSCT and mesenchymal stem cell therapy are experimental options for younger patients with high inflammatory activity.

CONCLUSIONS

SPMS and PPMS are being studied for new treatments and future trials should consider combination therapies targeting inflammation, demyelination, and neuronal death, as the pathogenesis of PMS involves complex factors.

Comparing Clinical and Radiological Features in Familial and Sporadic Multiple Sclerosis

Objective To compare the initial presentation, clinical features, disease courses, and radiological parameters between familial multiple sclerosis (fMS) and sporadic multiple sclerosis (sMS) to determine if the two represent distinct clinical entities. Methods This retrospective study was conducted at the Neurology Clinic at Kocaeli University Hospital. Records of 114 fMS and 150 sMS patients, aged 18-65, diagnosed based on either the Poser criteria or the McDonald 2001 criteria were analyzed. Radiological data and Expanded Disability Status Scale (EDSS) evaluations were conducted by a specialist neurologist. Variables included age at MS onset, first symptoms, relapses, EDSS scores at diagnosis and last examination, and MRI findings. Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 28, Armonk, NY) was utilized for data analysis. Results Both fMS and sMS groups were comparable in age (43.55±12.50 and 42.35±10.61 years, respectively) and gender distribution (females: fMS 71.9%, sMS 71.3%). No significant difference was noted regarding disease onset age (fMS 29.83±10.77, sMS 30.42±9.7). Age of onset, final EDSS, and relapse rate didn't significantly vary among sMS, fMS with first-degree relatives having MS (fMS(1)), and fMS with second or third-degree relatives having MS (fMS(2)). The fMS group showed a significantly higher incidence of initial spinal cord lesions on MRI compared to the sMS group (38.6% vs. 17.3%; p<0.001). Within the fMS group, the presence of spinal cord lesions on initial MRI correlated with a higher relapse rate and elevated initial and final EDSS scores. Conclusion Despite overarching similarities between fMS and sMS, spinal cord lesions' prevalence and implications in fMS may point to a genetic underpinning warranting in-depth exploration.

A systematic review of the safety and efficacy of monoclonal antibodies for progressive multiple sclerosis

BACKGROUND

Progressive multiple sclerosis (PMS) is a debilitating condition characterized by progressively worsening symptoms. Monoclonal antibodies are novel therapies for MS, but their safety and efficacy in the progressive form have not been comprehensively studied. In this systematic review, we aimed to evaluate the available evidence regarding monoclonal antibody treatment for PMS.

METHODS

After registration of the study protocol in PROSPERO, we systematically searched three major databases for clinical trials involving monoclonal antibodies administration for PMS treatment. All the retrieved results were imported into the EndNote reference manager. After removing the duplicates, two independent researchers did the study selection and data extraction. The risk of bias was assessed using the Joanna Briggs Institute (JBI) checklist.

RESULTS

Of the 1846 studies in the preliminary search, 13 clinical trials investigating monoclonal antibodies (Ocrelizumab, Natalizumab, Rituximab, and Alemtuzumab) in PMS patients were included. Ocrelizumab was significantly effective in reducing clinical disease progression measures in primary PMS patients. The results for Rituximab were not completely reassuring and only showed significant changes for some endpoints on MRI and clinical measures. Natalizumab decreased the relapse rate and improved MRI features for secondary PMS patients, but not clinical endpoints. The studies on Alemtuzumab treatment revealed conflicting outcomes, with improvements observed in MRI endpoints but clinical worsening in patients. Additionally, among the studied adverse events, upper respiratory infections, urinary tract infections, and nasopharyngitis were frequently reported.

CONCLUSION

Based on our findings, Ocrelizumab is the most efficient monoclonal antibody for primary PMS, although it is associated with a higher risk of infection. While other monoclonal antibodies did not show significant promise in treating PMS, more research is necessary.

Familial neuromyelitis optica spectrum disorders: Case series and systematic review

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) is considered a complex multifactorial disorder. Most cases are sporadic, and familial NMOSD is assumed as a rare occurrence. However, few studies reported familial aggregation of the disorder.

OBJECTIVES

To report familial NMOSD cases in Thailand and conduct a systematic review of familial NMOSD.

METHODS

A retrospective chart review of familial NMOSD patients at the university hospital was performed. Articles related to "genetic" and "NMOSD" were systematically searched and reviewed. We included NMOSD patients whose one or more relatives were diagnosed with the same disease or multiple sclerosis (MS). Data regarding demographics, clinical features, disease outcomes, and genetic testing were collected and analyzed using descriptive statistics.

RESULTS

We identified 6 familial cases from 165 NMOSD cases (3.6%) at our hospital and gathered 77 cases from a systematic review, totaling 83 cases from 40 families. The mean (SD) age at onset was 37.2 (18.0) years. Familial NMOSD involved 1-2 generations with mainly 2 affected individuals. The most common kinship pattern was siblingship in 21 families (52.5%). Initial syndromes were mostly optic neuritis and transverse myelitis. Serum aquaporin-4 IgG was positive in 79.7% of cases. Median number of relapses was 3 (range 1-26). Median expanded disability status scale in the last visit was 2 (range 0-8). Reported human leukocyte antigens (HLA) alleles shared between familial cases were HLA-A*01 and HLA-DRB1*03.

CONCLUSION

Familial clustering of NMOSD is more common than would be expected in the general population. The demographic, clinical, and outcome profiles of familial cases were not different from sporadic cases. Certain specific HLA haplotypes were shared among familial cases. Our systematic review highlighted complex genetic predisposition to NMOSD.

Epidemiology of familial multiple sclerosis and its comparison to sporadic form in Markazi Province, Iran

BACKGROUND

Limited data have been published about the epidemiology of familial multiple sclerosis (FMS) and its comparison to the sporadic form. Additionally, the epidemiology of FMS varies significantly in numerous provinces of Iran.

OBJECTIVES

The current study aimed to establish the epidemiology and clinical presentations of FMS and compare this form of the disease to sporadic multiple sclerosis (SMS) in Markazi province, Iran.

METHODS

In this cross-sectional registry-based study, the data were collected by the Multiple Sclerosis (MS) Society of Markazi province within 2012-2021. The demographic and clinical characteristics, diagnosis, and treatment of the MS patients living in the province were registered in this system.

RESULTS

A total of 924 MS cases who completed the data about the familial history of MS participated in this study. Based on the results, the female/male ratios were equal to 3.11 and 3.96 in FMS and SMS groups, respectively. Furthermore, 29.4% of the individuals had a history of the disease in their first- to third-degree relatives. The prevalence of primary-progressive multiple sclerosis was higher among the FMS patients (8.5%) than in the SMS patients (4.6%). Along with motor, sphincter, cognitive, and brain stem signs as the onset symptoms, the FMS group experienced a higher rate of polysymptomatic onset (P = 0.000). Moreover, significantly more autoimmune diseases and consanguineous marriages (P = 0.000) were observed in the FMS group than in the SMS group. The individuals with FMS reported a higher mean number of recurrences and higher Expanded Disability Status Scale (EDSS) scores (P = 0.000).

CONCLUSION

The results showed a significant prevalence of FMS in Markazi province. The FMS and SMS patients were significantly different regarding first presentations, onset symptoms, MS clinical characteristics, and EDSS scores. Finally, consanguineous marriage was significantly more common in the FMS group than in the SMS group.

Optical coherence tomography assessment of axonal and neuronal damage of the retina in patients with familial and sporadic multiple sclerosis

Objective

To assess axonal and neuronal damage of the retina in patients with familial (fMS) and sporadic multiple sclerosis (sMS).

Methods

87 relapsing-remitting MS patients (45 patients with sMS, 42 patients with fMS) and 30 healthy controls were included in the study. Optical coherence tomography (OCT) was performed with the spectral domain optical coherence tomography (SD-OCT, Heidelberg Engineering, Germany). The peripapillary retinal nerve fiber layer (pRNFL) thickness, ganglion cell-inner plexiform layer (GCIPL) thickness, total macular volume (TMV) and the inner nuclear layer (INL) thickness were measured.

Results

A significant reduction of the pRNFL thickness was detected in sMS and fMS compared to the control group (86.29 (+/- 16.13) μm in sMS, 84.78 (+/- 12.92) μm in fMS, 98.93 (+/- 6.71) μm in control group; p < 0.001). There was no significant difference in the pRNFL thickness between sMS and fMS (p = 0.5239). The GCIPL thickness was significantly decreased in sMS and fMS compared to the control group [66.0581 (+/- 11.2674) μm in sMS, 63.8386 (+/-10.004) μm in fMS, 76.5074 (+/- 5.0004) μm in control group; p < 0.001]. A significant reduction of the TMV was shown in sMS and fMS compared to the control group [8.4541(+/- 0.4727) mm3 in sMS, 8.3612 (+/- 0.4448) mm3 in fMS, 8.8387 (+/- 0.314) mm3 in control group; p < 0.0011]. No difference in the GCIPL thickness and TMV between sMS and fMS was found (p = 0.3689 and p = 0.3758, respectively). The INL thickness in sMS and fMS did not differ compared to the control group [34.2323 (+/- 2.7006) μm in sMS, 34.5159 (+/- 2.9780) μm in fMS, 33.6148 (+/- 2.0811) μm in control group; p = 0.5971 and p = 0.1870, respectively] and between the two forms (p = 0.4894).

Conclusion

We confirmed the presence of axonal and neuronal damage of the retina in sMS and fMS. Both forms of MS did not differ significantly from each other with respect to RFNL, GCIPL, MV and INL. ON induced significant reduction of the pRNFL, GCIPL and MV in both groups of pwMS.

Disease-Modifying Treatments and Time to Loss of Ambulatory Function in Patients With Primary Progressive Multiple Sclerosis

Importance

Except for ocrelizumab, treatment options in primary progressive multiple sclerosis (PPMS) are lacking.

Objective

To investigate the effectiveness of DMTs on the risk of becoming wheelchair dependent in a real-world population of patients with PPMS.

Design, Setting, and Participants

This was a multicenter, observational, retrospective, comparative effectiveness research study. Data were extracted on November 28, 2018, from the Italian multiple sclerosis register and analyzed from June to December 2021. Mean study follow-up was 11 years. Included in the study cohort were patients with a diagnosis of PPMS and at least 3 years of Expanded Disability Status Scale (EDSS) evaluations and 3 years of follow-up.

Main Outcomes and Measures

The risk of reaching an EDSS score of 7.0 was assessed through multivariable Cox regression models.

Exposures

Patients who received DMT before the outcome were considered treated. DMT was assessed as a time-dependent variable and by class of DMT (moderately and highly effective).

Results

From a total of 3298 patients with PPMS, 2633 were excluded because they did not meet the entry criteria for the phase 3, multicenter, randomized, parallel-group, double-blind, placebo-controlled study to evaluate the efficacy and safety of ocrelizumab in adults with PPMS (ORATORIO) trial. Among the remaining 665 patients (mean [SD] age, 43.0 [10.7] years; 366 female patients [55.0%]), 409 were further selected for propensity score matching (288 treated and 121 untreated patients). In the matched cohort, during the study follow-up, 37% of patients (152 of 409) reached an EDSS score of 7.0 after a mean (SD) follow-up of 10.6 (5.6) years. A higher EDSS score at baseline (adjusted hazard ratio [aHR], 1.32; 95% CI, 1.13-1.55; P < .001), superimposed relapses (aHR, 2.37; 95% CI, 1.24-4.54; P = .009), and DMT exposure (aHR, 1.75; 95% CI, 1.04-2.94; P = .03) were associated with a higher risk of an EDSS score of 7.0, whereas the interaction term between DMT and superimposed relapses was associated with a reduced risk of EDSS score of 7.0 (aHR, 0.33; 95% CI, 0.16-0.71; P = .004). Similar findings were obtained when treatment according to DMT class was considered and when DMT was included as a time-dependent covariate. These results were confirmed in the subgroup of patients with available magnetic resonance imaging data.

Conclusions and Relevance

Results of this comparative effectiveness research study suggest that inflammation also occurs in patients with PPMS, may contribute to long-term disability, and may be associated with a reduced risk of becoming wheelchair dependent by current licensed DMTs.

Clinical and prognostic aspects of patients with the Neuromyelitis Optica Spectrum Disorder (NMOSD) from a cohort in Northeast Brazil

Introduction

Neuromyelitis optica spectrum disorders (NMOSD) is a rare inflammatory and demyelinating disease of the central nervous system (CNS) more frequent in women and Afro-descendants. No previous epidemiological or prognostic study has been conducted in the region of the state of Bahia, Brazilian Northeast.

Objective

To evaluate clinical and prognostic aspects in patients with NMOSD from a cohort in northeastern Brazil.

Material and methods

A single-center retrospective study was conducted with consecutive patients diagnosed with NMOSD. Clinical and epidemiological characteristics were described. The degree of disability was expressed by the Expanded Disability Status Scale (EDSS). Worsening disability were analyzed through negative binomial regression adjusted for disease duration.

Results

Ninety-one patients were included, 72 (79.1%) female and 67 (73.6%) afro descendants. Mean age at onset was 36 (± 14) years and 73.3% were anti-aquaporin-4 antibody positive. Isolated transverse myelitis (32.9%) and isolated optic neuritis (22.4%) were the most frequent initial clinical syndromes. After multivariate analysis, optic neuritis (RR = 0.45; 95% CI = 0.23 – 0.88; p = 0.020) and dyslipidemia (RR = 0.40; 95% CI = 0.20 – 0.83; p = 0.014) were associated with slower disease progression. Area postrema involvement (RR = 6.70; 95% CI = 3.31 – 13.54; p < 0.001) and age at onset (RR = 1.03; 95% CI = 1.01 – 1.05; p = 0.003) were associated with faster disease progression.

Conclusions

In the first clinical and prognostic study in northeastern Brazil, we identified area postrema involvement, age at onset, optic neuritis at fist syndrome and dyslipidemia as the main prognostic factors associated with disease progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02621-5.

• Isolated transverse myelitis was the most frequent initial clinical syndrome.

• Optic neuritis as first clinical syndrome was independently associated with better prognostic.

• Age at onset were associated with faster disease progression.

• Hashimoto's thyroiditis was the most frequent autoimmune disease in NMOSD.

Prevention of MS Requires Intervention on the Causes of the Disease: Reconciling Genes, Epigenetics, and Epstein Barr Virus

Prevention of multiple sclerosis requires intervention on modifiable causes of the condition making it necessary to establish what those causes are. MS is often stated to be a polygenic disease, with causal contributions from environmental factors and gene-environment interactions, implying an additive and independent relationship of these factors. Mechanistically there are no independent contributions of genes or environmental factors to traits. This model is unrealistic but still useful and underlies the concept of heritability, a foundational parameter in population genetics. However, it perpetuates a debate on an irreconcilable dichotomy about whether MS is primarily genetic or environmental. In particular, epidemiological evidence now exists for a causal, possibly even necessary, role for Epstein Barr Virus in MS. The additive model makes it unintuitive to reconcile MS as a genetic disease but also independently a viral illness. In this perspective it is argued that starting from a realistic interaction only model, based on broadly accepted biological premises, and working forward to explain why the classical additive model gives useful results, there is actually no paradox. An integrated approach using population genetic studies, immunology and molecular virology offers a particularly promising route to establish the elusive role of EBV in MS pathology, as EBV is a large and complex virus and its latency, dysregulated in most EBV-related pathologies, is hard to study in vivo. This approach may offer a route to prevention of MS altogether.

How have Economic Evaluations in Relapsing Multiple Sclerosis Evolved Over Time? A Systematic Literature Review

INTRODUCTION

The introduction of disease-modifying therapies (DMTs) for relapsing multiple sclerosis (RMS) over the last two decades has prompted the economic assessments of these treatments by reimbursement authorities. The aim of this systematic literature review was to evaluate the modeling approach and data sources used in economic evaluations of DMTs for RMS, identify differences and similarities, and explore how economic evaluation models have evolved over time.

METHODS

MEDLINE®, Embase®, and EBM Reviews databases were searched using Ovid® Platform from database inception on 25 December 2019 and subsequently updated on 17 February 2021. In addition, health technology assessment agency websites, key conference proceedings, and gray literature from relevant websites were screened. The quality of included studies was assessed using the Drummond and Philips checklists.

RESULTS

A total 155 publications and 30 Health Technology Assessment (HTA) reports were included. Most of these were cost-utility analysis (73 studies and 25 HTA reports) and funded by medicines manufacturers (n = 65). The top three countries where studies were conducted were the USA (n = 29), the UK (n = 16), and Spain (n = 10). Studies predominantly used Markov cohort models (94 studies; 25 HTAs) structured based on the Expanded Disability Status Scale (EDSS) with 21 health states (20 studies; 12 HTA reports). The London Ontario and British Columbia data sets were commonly used sources for natural history data (n = 33; n = 13). Twelve studies and ten HTAs from the UK assumed a waning of DMT effect over the long term, while this was uncommon in studies from other countries. Nineteen studies adjusted for multiple sclerosis (MS)-specific mortality estimates, while 18 studies used data from the national life table without adjustment. Studies prominently referred to mortality data that were about two decades old. The data on treatment effect was generally obtained from randomized controlled trials (43 studies; 7 HTAs) or from published evidence synthesis (23 studies; 24 HTAs). Utility estimates were derived from either published studies and/or supplemented with data from RCTs. Most of the models used the lifetime horizon (n = 37) with a 1-year cycle length (n = 63).

CONCLUSION

As expected, similarities as well as differences were observed across the different economic models. Available evidence suggests models should continue using the Markov cohort model with 21 EDSS-based states, however, allowing the transition to a lower EDSS state and assuming a sustained treatment effect. With reference to the data sources, models should consider using a contemporary MS-specific mortality data, recent natural history data, and country-specific utility data if available. In case of data unavailability, a sensitivity analysis using multiple sources of data should be conducted. In addition, future models should incorporate other clinically relevant outcomes, such as the cognition, vision, and psychological aspects of RMS, to be able to present the comprehensive value of DMTs.

The global prevalence of familial multiple sclerosis: an updated systematic review and meta-analysis

BACKGROUND

Considering that many recent studies have reported the prevalence of familial multiple sclerosis (FMS), we performed an updated meta-analysis of the worldwide prevalence of FMS by the addition of recent publications.

METHODS

A search in PubMed, Scopus, the ISI Web of Science, and Google Scholar was undertaken up to 20 December 2020. The inclusion criteria were based on the CoCoPop approach (condition, context, and population). Meta-analysis of the qualified studies was conducted by comprehensive meta-analysis ver. 2 software.

RESULTS

The pooled prevalence of MS in relatives of 16,179 FMS cases was estimated to be 11.8% (95% CI: 10.7-13) based on a random-effects model. The pooled mean age of disease onset in adult probands was calculated to be 28.7 years (95% CI: 27.2 ± 30.2). Regarding 13 studies that reported the data of FMS in pediatrics (n = 877) and adults (n = 6636), the FMS prevalence in pediatrics and adults was 15.5% (95% CI: 13.8-17.4) and 10.8% (95% CI: 8.1-14.2), respectively. The prevalence of FMS in affected males (n = 5243) and females (n = 11,503) was calculated to be 13.7% (95% CI: 10.1-18.2) and 15.4% (95% CI: 10.3-22.4), respectively. The odds ratio of male/female in FMS cases was not statistically significant (OR = 0.9; 95% CI: 0.6-1.2, P = 0.55). Subgroup analysis demonstrated a significant difference in the prevalence of FMS between the geographical areas (P = 0.007). The meta-regression model indicated that the prevalence of FMS is lower with higher latitude and higher MS prevalence (P < 0.001). In contrast, meta-regression based on prevalence day was not statistically significant (P = 0.29).

CONCLUSIONS

The prevalence of FMS is higher in the pediatric group than that of adults, distinct between geographical areas, and diminishes with the increment of MS prevalence and latitude. Also, the symptoms initiate relatively at younger ages in the FMS cases. Interestingly, our analysis unveiled that FMS is not more prevalent in men than women and the risk of MS development in relatives is not higher when the affected proband is male.

Genes and environment in multiple sclerosis: Impact of temporal changes in the sex ratio on recurrence risks

Objective:

To evaluate the impact of temporal increase of female to male (F:M) sex ratio for persons with multiple sclerosis (MS) on the familial risk (empiric recurrence risks or RRs) for biological relatives of affected individuals.

Methods:

Detailed family histories were systematically obtained from people with MS attending the University of British Columbia Hospital MS Clinic. The study cohort was born in 1970 or more recently. Data were collected from 1 September 2015 to 31 January 2019. The study was designed to allow only one proband per family. Age-corrected RRs for biological relatives of probands were calculated based on a modification of the maximum-likelihood approach.

Results:

Data analyses were possible for 746 unique probands (531 females; 215 males) and 19,585 of their biological relatives. RRs were temporally impacted.

Conclusion:

Both genetic sharing and environmental factors are important in determining RRs. It appears that there is an increase in MS risk due to environmental factors in later life (i.e. not shared family environment). Environmental exposures in genetically predisposed individuals might be driving the MS risk. The increase in F:M ratio of RRs for sisters/brothers of female probands over time is likely due to environmental differences.

Risk of secondary progressive multiple sclerosis: A longitudinal study

Background:

The risk factors for conversion from relapsing-remitting to secondary progressive multiple sclerosis remain highly contested.

Objective:

The aim of this study was to determine the demographic, clinical and paraclinical features that influence the risk of conversion to secondary progressive multiple sclerosis.

Methods:

Patients with adult-onset relapsing–remitting multiple sclerosis and at least four recorded disability scores were selected from MSBase, a global observational cohort. The risk of conversion to objectively defined secondary progressive multiple sclerosis was evaluated at multiple time points per patient using multivariable marginal Cox regression models. Sensitivity analyses were performed.

Results:

A total of 15,717 patients were included in the primary analysis. Older age (hazard ratio (HR) = 1.02, p < 0.001), longer disease duration (HR = 1.01, p = 0.038), a higher Expanded Disability Status Scale score (HR = 1.30, p < 0.001), more rapid disability trajectory (HR = 2.82, p < 0.001) and greater number of relapses in the previous year (HR = 1.07, p = 0.010) were independently associated with an increased risk of secondary progressive multiple sclerosis. Improving disability (HR = 0.62, p = 0.039) and disease-modifying therapy exposure (HR = 0.71, p = 0.007) were associated with a lower risk. Recent cerebral magnetic resonance imaging activity, evidence of spinal cord lesions and oligoclonal bands in the cerebrospinal fluid were not associated with the risk of conversion.

Conclusion:

Risk of secondary progressive multiple sclerosis increases with age, duration of illness and worsening disability and decreases with improving disability. Therapy may delay the onset of secondary progression.

Distribution of disease courses in familial vs sporadic multiple sclerosis

OBJECTIVES

The overall distribution of disease courses in multiple sclerosis (MS) is well established, but little is known about the distribution among familial MS cases. We examine the frequency of the different MS courses among familial and sporadic MS cases and determine whether MS cases within the same family had the same age at diagnosis and have experienced the same disease course.

MATERIALS AND METHODS

This is a nationwide register study, based on data from the Danish MS Registry, the Danish Civil Registration System, and the Danish National Patient Registry. The main variables are MS diagnosis, MS course, and first-degree relatives with MS The statistical analyses were carried out using logistic regression analysis, Kappa coefficient, and intraclass correlations coefficient.

RESULTS

In total, 7402 MS cases were included in the study, of which 531 have an affected first-degree relatives, and 6871 are sporadic. We found that relapsing-remitting MS including secondary progressive MS was more common among familial MS cases than among sporadic MS cases (Odds ratio = 1.64, 95% CI: 1.20-2.24, P = 0.002). We subsequently analyzed data on 133 MS families and found that MS courses correlate between the first and the second MS case diagnosed, while age at diagnosis does not.

CONCLUSION

Familial MS cases are more likely to have relapsing-remitting MS than a progressive course compared to sporadic MS cases. Secondly, we find that within MS families, first-degree relatives are likely to have the same MS course, but we do not find that they are diagnosed at the same age.

Familial multiple sclerosis in a Brazilian sample: Is HLA-DR15 involved in susceptibility to the disease?

BACKGROUND

The HLA-DR15 extended haplotype HLA-DRB1*15:01-DQA1*01:02-DQB1*06:02 comprises the strongest genetic risk factor for multiple sclerosis (MS). The aim of this work was to investigate whether HLA-DR15 alleles were significantly associated with the susceptibility to MS familial forms (MSf) in an admixed Brazilian population.

METHODS

Association analyses between DR15 and the clinical and demographic variables were made.

RESULTS

We have genotyped 25 familial cases. The DR15 was detected in 11/25 (44%) of them and in none of controls (P < .00001). DR15 was significantly associated to a foreign ancestor background (P = .029) and later age of onset (P = .018).

[Familial multiple sclerosis in Tomsk region]

AIM

Multiple sclerosis (MS) has a multifactorial etiology. To explore a role of genetic factors in the pathogenesis of MS, the authors studied familial cases of MS.

MATERIAL AND METHODS

For an analysis of familial cases, a database of 320 MS patients registered in Tomsk region since 1980 till 2014 was used. The following items for each patient were recorded: disease onset, manifestation of disease, duration of first remission, rate of progression of disease.

RESULTS AND CONCLUSION

Nine families with several members with MS were identified. In 2014, the frequency of familial cases in the MS population of Tomsk region was 4.7%. The prevalence of familial MS was 1.4 cases per 100.000 of people. The younger age at disease onset and higher rate of disease progression measured with the EDSS in parent-child pairs were identified. The most families with several members with MS were characterized by clinical polymorphism of onset, duration and rate of disease progression.

Multiple sclerosis and neuromyelitis optica spectrum disorders in Malaysia: A comparison in different ethnic groups

We performed a retrospective observational analytical study looking at the frequencies and characteristics of multiple sclerosis(MS) and neuromyelitis optica spectrum disorders(NMOSD) in consecutive patients with idiopathic inflammatory demyelinating disease (IIDDs) attending three centers (2009-2017). Of 523 patients with IIDDs, there were 173 patients with NMOSD and 230 patients with MS. The percentage of NMOSD: IIDDs was 33%. The percentage of NMOSD:Total MS and NMOSD cohort was 43%. Of 141 seropositive NMOSD patients, 134(95%) were from the three main ethnic groups. The percentage of seropositive NMOSD to IIDDs and to combined MS and NMOSD was 26.9% and 35% respectively. Ratios of MS to NMOSD were nearly equal at 1.3 to 1.0, reinforcing the high ratio of NMOSD to MS in Asia. Nearly half of the Chinese cohort were seropositive ie; 71/141 (50%) with the remainder being Malays; 56/141 (39.7%) and Indians; 7/141 (5%). Amongst the other indigenous groups seropositivity was seen in 2 each of Iban, Bajau, Kadazan descent as well as one of Bidayuh origin. Comparatively, seropositivity in NMOSD is commoner amongst the Chinese compared to the Malays (p ≤ 0.005) and Indians, p ≤ 0.05 with ratios as high as 10:1. In the MS group of 230 subjects, 123(53.5%) were Malays (ratio of MS:NMOSD of 2:1), 41(17.8%) were Chinese, (ratio of MS:NMOSD of 0.5:1.0) and 54 (23.5%)were Indians (ratios of MS:NMOSD of 5:1 amongst the Indians). The remainder from East Malaysia were made up of 2 each of Kadazans, Ibans and Bajaus including 3 each of Bidayuh and Eurasian descent. Comparatively, in the NMOSD and MS cohorts a female preponderance was noted more so amongst Chinese NMOSD patients, with rare familial occurrence in both but more in Malay MS/NMOSD patients. This study also highlighted some of the inter-ethnic differences in presentation of MS and NMOSD amongst the 3 main ethnic races in Malaysia and confirms indigenous races having MS/NMOSD which needs further research. It also reviewed current literature on similar inter-ethnic differences world wide. To conclude, MS and NMOSD are the commonest demyelinating diseases seen in Malaysia with interesting inter-ethnic differences and similarities.

Linkage analysis and whole exome sequencing identify a novel candidate gene in a Dutch multiple sclerosis family

BACKGROUND

Multiple sclerosis (MS) is a complex disease resulting from the joint effect of many genes. It has been speculated that rare variants might explain part of the missing heritability of MS.

OBJECTIVE

To identify rare coding genetic variants by analyzing a large MS pedigree with 11 affected individuals in several generations.

METHODS

Genome-wide linkage screen and whole exome sequencing (WES) were performed to identify novel coding variants in the shared region(s) and in the known 110 MS risk loci. The candidate variants were then assessed in 591 MS patients and 3169 controls.

RESULTS

Suggestive evidence for linkage was obtained to 7q11.22-q11.23. In WES data, a rare missense variant p.R183C in FKBP6 was identified that segregated with the disease in this family. The minor allele frequency was higher in an independent cohort of MS patients than in healthy controls (1.27% vs 0.95%), but not significant (odds ratio (OR) = 1.33 (95% confidence interval (CI): 0.8-2.4), p = 0.31).

CONCLUSION

The rare missense variant in FKBP6 was identified in a large Dutch MS family segregating with the disease. This association to MS was not found in an independent MS cohort. Overall, genome-wide studies in larger cohorts are needed to adequately investigate the role of rare variants in MS risk.

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.

Environmental factors in the development of multiple sclerosis

Epidemiology of Multiple Sclerosis (MS) has been intensively studied and we know now that its occurrence result from the combined action of genetic and environmental factors. There are significant geographic and temporal variations in MS incidence and the risk associated with the development of MS may be affected by many potential factors (including infections, climate, diet, etc.). But none of these factors has been identified as "causal". The accumulation of these different agents as well as their interactions probably contribute to the development of the disease.

Increasing prevalence of familial recurrence of multiple sclerosis in Iran: a population based study of Tehran registry 1999-2015

BACKGROUND

Tehran is the capital of Iran with an increasing multiple sclerosis (MS) prevalence. A retrospective population-based study was conducted to evaluate the trends of MS prevalence in Tehran.

METHODS

A population-based survey was conducted for the period 1999 to 2015, based on Iranian MS Society (IMSS) registry system of Tehran, the capital city of Iran. Point regression analysis was applied on MS trend data to find annual percent change (APC). The logistic regression analysis was used to estimate the odds ratio (OR) for individual variables in order to assess factors associating with familial recurrence of MS. P values < 0.05 were considered significant.

RESULTS

MS prevalence has significantly increased during the study period from 1999 to 2015 (56.22 per 100,000). Total point prevalence of MS was 115.94 per 100,000 persons in 2015 compared to general population. Positive family history of MS was observed among 12.4% of patients. The strongest association amongst first-degree relatives was found in siblings, p value ≤ 0.001.

CONCLUSION

MS prevalence is rising in Tehran and this city is one of the regions with highest MS prevalence in Asia. In this sample, the largest proportion of relatives with MS were found among first-degree relatives, particularly siblings. Familial recurrence correlated with relative type.

HLA-DRB1*15 association with multiple sclerosis is confirmed in a multigenerational Italian family

Environmental and genetic factors seem to play a pathogenetic role in multiple sclerosis (MS). The genetic component is partly suggested by familial aggregation of cases; however, MS families with affected subjects over different generations have rarely been described. The aim of this study was to report clinical and genetic features of a multigenerational MS family and to perform a review of the literature on this topic. We describe a multigenerational Italian family with six individuals affected by MS, showing different clinical and neuroradiological findings. HLA-DRB1* typing revealed the presence of the DRB1*15:01 allele in all the MS cases and in 4/5 non-affected subjects. Reports on six multigenerational MS families have previously been published, giving similar results. The HLA-DRB1*15:01 allele was confirmed to be linked to MS disease in this family; moreover, its presence in non-affected subjects suggests the involvement of other susceptibility factors in the development and expression of the disease, in accordance with the complex disease model now attributed to MS.

Worldwide prevalence of familial multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Several studies have suggested that the existence of a history of multiple sclerosis (MS) in family, is one of the predisposing factors for MS. Based on our knowledge, the review and estimation of the prevalence of familial multiple sclerosis (FMS) in the world has not been reported up to now. This study is a systematic review and a meta-analysis of FMS prevalence in the world.

METHODS

Two researchers searched "epidemiology" or "prevalence" or "incidence" and "familial multiple sclerosis" as relevant keywords in international databases such as PubMed, web of science and Scopus up to 2016. MedCalc Version 15.8 was used to estimate the pooled prevalence of FMS. (PROSPERO ID = CRD42016033016) RESULTS: From the 184 total articles found from 1954 to 2016, we pooled and analyzed the data of 17 final eligible studies, according to the inclusion criteria. The prevalence of FMS was estimated as 12.6% within a total sample size of 14,619 MS patients in the world as of 95% confidence interval (CI: 9.6-15.9).

CONCLUSION

We detected significant heterogeneity from Hungary to Saskatchewan for FMS prevalence that was not latitude and ethnicity dependent. This highlighted the accumulation effects of genetic and environment on FMS prevalence. Pooled prevalence of FMS in MS population was calculated 12.6% by random effect in the world.

Burden of genetic risk variants in multiple sclerosis families in the Netherlands

Background

Approximately 20% of multiple sclerosis patients have a family history of multiple sclerosis. Studies of multiple sclerosis aggregation in families are inconclusive.

Objective

To investigate the genetic burden based on currently discovered genetic variants for multiple sclerosis risk in patients from Dutch multiple sclerosis multiplex families versus sporadic multiple sclerosis cases, and to study its influence on clinical phenotype and disease prediction.

Methods

Our study population consisted of 283 sporadic multiple sclerosis cases, 169 probands from multiplex families and 2028 controls. A weighted genetic risk score based on 102 non-human leukocyte antigen loci and HLA-DRB1*1501 was calculated.

Results

The weighted genetic risk score based on all loci was significantly higher in familial than in sporadic cases. The HLA-DRB1*1501 contributed significantly to the difference in genetic burden between the groups. A high weighted genetic risk score was significantly associated with a low age of disease onset in all multiple sclerosis patients, but not in the familial cases separately. The genetic risk score was significantly but modestly better in discriminating familial versus sporadic multiple sclerosis from controls.

Conclusion

Familial multiple sclerosis patients are more loaded with the common genetic variants than sporadic cases. The difference is mainly driven by HLA-DRB1*1501. The predictive capacity of genetic loci is poor and unlikely to be useful in clinical settings.

Familial forms of multiple sclerosis and neuromyelitis optica at an MS center in Rio de Janeiro State, Brazil

OBJECTIVE

To describe familial forms of demyelinating diseases from an MS referral center in Río de Janeiro State, Brazil.

METHODS

A descriptive, cross-sectional study was done to identify familial IIDD cases in Hospital da Lagoa, a public hospital where 75% of patients with IIDD who live in Rio de Janeiro state, located in the Southeast region of Brazil, are referred. The diagnoses of all consecutive patients followed in 2011 were reviewed to apply new diagnostic criteria (Wingerchuk et al., 2008). The diagnosis of IIDD was confirmed based on clinical history, neurological examination, MRI of the skull and spinal cord, CSF analysis and investigation of IgG NMO antibodies. The cases that had at least one other relative with IIDD were selected for the study.

RESULTS

Familial forms were found only in the multiple sclerosis (MS) and neuromyelitis optica syndrome (NMOSD) categories. 23 MS families were identified, 60.86% with first degree kinship. It has a Caucasian preponderance, 90% of whom were white. The frequency of early onset was 15% and 20% of the MSf cases have progressive primary course.

CONCLUSION

The frequency of familial cases of IIDD was 6.12% among MS patients and 2.8% in NMO spectrum syndromes.

The prevalence of familial multiple sclerosis in saskatoon, Saskatchewan

Background. A population-based prevalent cohort of 150 clinical definite multiple sclerosis (MS) cases (102 women; 48 men) ascertained on January 1, 1977, Saskatoon, Saskatchewan, was found to have a familial rate of MS as 17.3%. Objectives. To determine the occurrence of familial MS cases and the frequency of MS among the biological relatives of the study cohort. Methods. The search for new familial cases MS affected relatives continued for 35 years until 2012. The natural history of the disease of sporadic cases is compared with that of the familial cases. SPSS V19 and Kaplan-Meier survival analysis were used for data analysis. Results. Of the 150 unrelated MS patients, 49 cases (32.7%) (36 women and 13 men) were reported of having at least one family member with MS. There were a total of 86 affected relatives, 26 (30.2%) first-degree relatives, 15 (17.4%) second-degree relatives, 20 (23.3%) third-degree relatives, and 25 (29.1%) distant relatives. The average age of MS onset for men with sporadic MS was 33.9 (SD = 10) years and 27.6 (SD = 8.4) years for familial cases and 29.3 (SD = 8.3) years and 26.8 (SD = 8.5) years for women. Conclusion. This 35-year longitudinal natural history study reveals a high frequency of cases with family members developing MS and supports a genetic influence in the etiology of MS.

Prevalence of radiologically isolated syndrome and white matter signal abnormalities in healthy relatives of patients with multiple sclerosis

BACKGROUND AND PURPOSE

The exact prevalence of WM signal abnormalities in healthy relatives of MS patients and their impact on disease development has not been fully elucidated. The purpose of this study was to compare WM signal abnormality characteristics and the prevalence of radiologically isolated syndrome in healthy control subjects selected randomly from the population with the healthy relatives of patients with MS.

MATERIALS AND METHODS

Healthy control subjects (n = 150) underwent physical and 3T MR imaging examinations. Healthy control subjects were classified as non-familial healthy control subjects (n = 82) if they had no family history of MS or as healthy relatives of patients with MS (n = 68) if they had ≥1 relative affected with MS. The presence of radiologically isolated syndrome was evaluated according to the Okuda criteria; dissemination in space on MR imaging and fulfillment of radiologically isolated syndrome criteria were also evaluated according to Swanton criteria.

RESULTS

There was a significantly higher total volume of WM signal abnormality in the healthy relatives of patients with MS compared with the non-familial healthy control subjects (P = .024 for signal abnormality ≥3 mm in size and P = .025 for all sizes). Periventricular localization and the number of lesions in all groups (P = .034 and P = .043) were significantly higher in the healthy relatives of patients with MS; 8.8% of the healthy relatives of patients with MS and 4.9% of non-familial healthy control subjects showed ≥9 WM signal abnormalities; 2.9% of subjects in the healthy relatives of patients with MS group and 2.4% of non-familial healthy control subjects fulfilled radiologically isolated syndrome according to the Okuda criteria, whereas 10.3% and 3.7% of subjects fulfilled radiologically isolated syndrome according to the Swanton criteria. In the healthy relatives of patients with MS, smoking was associated with the presence of WM signal abnormalities, whereas obesity was related to the presence of ≥9 WM signal abnormalities and to fulfillment of radiologically isolated syndrome according to the Swanton criteria.

CONCLUSIONS

The frequency of WM signal abnormalities and radiologically isolated syndrome is higher in the healthy relatives of patients with multiple sclerosis patients compared with non-familial healthy control subjects.

MRI characteristics of familial and sporadic multiple sclerosis patients

PURPOSE

To investigate the MRI characteristics in a large cohort of multiple sclerosis (MS) patients with and without a family history of MS.

METHODS

Enrolled in this prospective study were 758 consecutive MS patients (mean age 46.2 ± 10.1 years, disease duration 13.6 ± 9.2 years and EDSS 3.4 ± 2.1), of whom 477 had relapsing-remitting, 222 secondary-progressive, and 30 primary-progressive disease courses and 29 had clinically isolated syndrome. One hundred and ninety-six patients (25.9%) had a positive family history of MS. Patients were assessed using measurements of lesions, brain atrophy, magnetization transfer ratio (MTR) and diffusion-weighted imaging.

RESULTS

The familial MS group had greater T1-lesion volume (p=0.009) and a trend for lower MTR of T1-lesion volume (p=0.047) than the sporadic MS group. No clinical differences were found between familial versus sporadic group, or by a degree of affected relative subgroups.

CONCLUSIONS

While familial MS was associated with more severe T1-lesion volume and its MTR characteristics, there were no clinical status differences between familial and sporadic MS patients. Therefore, a better understanding of the genetic and/or epigenetic influences causing these differences can advance the understanding and management of MS.

Exome sequencing identifies a novel multiple sclerosis susceptibility variant in the TYK2 gene

OBJECTIVE

To identify rare variants contributing to multiple sclerosis (MS) susceptibility in a family we have previously reported with up to 15 individuals affected across 4 generations.

METHODS

We performed exome sequencing in a subset of affected individuals to identify novel variants contributing to MS risk within this unique family. The candidate variant was genotyped in a validation cohort of 2,104 MS trio families.

RESULTS

Four family members with MS were sequenced and 21,583 variants were found to be shared among these individuals. Refining the variants to those with 1) a predicted loss of function and 2) present within regions of modest haplotype sharing identified 1 novel mutation (rs55762744) in the tyrosine kinase 2 (TYK2) gene. A different polymorphism within this gene has been shown to be protective in genome-wide association studies. In contrast, the TYK2 variant identified here is a novel, missense mutation and was found to be present in 10/14 (72%) cases and 28/60 (47%) of the unaffected family members. Genotyping additional 2,104 trio families showed the variant to be transmitted preferentially from heterozygous parents (transmitted 16: not transmitted 5; χ(2) = 5.76, p = 0.016).

CONCLUSIONS

Rs55762744 is a rare variant of modest effect on MS risk affecting a subset of patients (0.8%). Within this pedigree, rs55762744 is common and appears to be a modifier of modest risk effect. Exome sequencing is a quick and cost-effective method and we show here the utility of sequencing a few cases from a single, unique family to identify a novel variant. The sequencing of additional family members or other families may help identify other variants important in MS.

Interferon beta for secondary progressive multiple sclerosis

BACKGROUND

Therapy with either recombinant beta-1a or beta-1b interferons (IFNs) is worldwide approved for Relapsing Remitting Multiple Sclerosis (RRMS). A major unanswered question is whether this treatment is able to safely reverse or retard the progressive phase of the disease.

OBJECTIVES

The main objective was to verify whether IFNs treatment in Secondary Progressive Multiple Sclerosis (SPMS) is more effective than placebo in reducing the number of patients who experience disability progression.

SEARCH METHODS

We searched the Cochrane Multiple Sclerosis Group's Trials Register (1995 to 15 February 2011), the reference lists of relevant articles and conference proceedings. Regulatory agencies were used as additional sources of information.

SELECTION CRITERIA

We included all randomised, double or single blind, placebo-controlled trials (RCTs) evaluating the efficacy of IFNs versus placebo in SPMS patients.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all reports retrieved from the search. They independently extracted clinical, safety and MRI data, using a predefined data extraction form, resolving disagreements after discussion with a third reviewer. Risk of bias was evaluated to assess the quality of the studies. Treatment effect was measured using Risk Ratio (RR) with 95% confidence intervals (CI) for the binary outcomes and Standard Mean Difference with 95% CI for the continuous outcomes.

MAIN RESULTS

Five RCTs met the inclusion criteria, from which 3122 (1829 IFN and 1293 placebo) treated patients contributed to the analysis. Included population was heterogeneous in terms of baseline clinical characteristics of the disease, in particular the percentage of patients affected by secondary progression with superimposed relapse ranging from 72% to 44%. IFN beta 1a and 1b did not decrease the risk of progression sustained at 6 months (RR, 95% CI: 0.98, [0.82-1.16]) after three years of treatment. A significant decrease of the risk of progression sustained at 3 months (RR, 95% CI: 0.88 [0.80, 0.97]) and of the risk of developing new relapses at three years (RR 0.91, [0.84-0.97]) were found. The risk of developing new active brain lesions decreased over time but this data was obtained from single studies on Magnetic Resonance Imaging (MRI), performed in subgroups of patients; in spite of no effect on progression, the radiological data supported an effect on MRI parameters. The safety profile reflects what is commonly reported in MS IFN-treated patients.

AUTHORS' CONCLUSIONS

Well designed RCTs, evaluating a high number of patients were included in the review. Recombinant IFN beta does not prevent the development of permanent physical disability in SPMS. We were unable to verify the effect on cognitive function for the lack of comparable data. This treatment significantly reduces the risk of relapse and of short -term relapse-related disability.Overall, these results show that IFNs' anti-inflammatory effect is unable to retard progression, when established. In the future, no new RCTs for IFNs versus placebo in SPMS will probably be undertaken, because research is now focusing on innovative drugs. We believe that this review gives conclusive evidence on the clinical efficacy of IFNs versus placebo in SPMS.

Demographic, genetic, and environmental factors that modify disease course

As with susceptibility to disease, it is likely that multiple factors interact to influence the phenotype of multiple sclerosis and long-term disease outcomes. Such factors may include genetic factors, socioeconomic status, comorbid diseases, and health behaviors, as well as environmental exposures. An improved understanding of the influence of these factors on disease course may reap several benefits, such as improved prognostication, allowing us to tailor disease management with respect to intensity of disease-modifying therapies and changes in specific health behaviors, in the broad context of coexisting health issues. Such information can facilitate appropriately adjusted comparisons within and between populations. Elucidation of these factors will require careful study of well-characterized populations in which the roles of multiple factors are considered simultaneously.

Genetics for understanding and predicting clinical progression in multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a dys-immune disease of the central nervous system with highly variable and unpredictable long-term outcome.

STATE OF THE ART

In the early 1970s association between HLA alleles and MS was established. Very recently, the power of Genome Wide Association Studies (GWAS) enabled the identification of several loci involved in immune functions as genetic risk factors in MS. Recent data suggest that common genetic variations might modulate the clinical phenotype of MS through a regulation of key pathophysiological pathways.

PERSPECTIVES

Identification of modifier genes might offer an opportunity to explore new relevant therapeutic targets and early prognostic markers. To date, studies of modifier genes in MS are numerous but results are still unclear. This research field may now benefit from large cohorts of patients available for association studies.

CONCLUSION

In this context, we propose a review of epidemiological and association studies of genetic modifying effect in MS.

Sibling disability risk at onset and during disease progression in familial multiple sclerosis

BACKGROUND

The objective of this study was to address the differences in onset and disease progression between familial and sporadic multiple sclerosis (MS) and the association within sibling pairs.

METHODS

Ninety-eight siblings and their controls were included from a database of 763 sporadic MS-patients, randomly pair-matched for age, gender, clinical course, disease duration and treatment. Sixty-eight available siblings completed a prospective six-year follow-up. Outcome parameters included baseline Expanded Disability Status Scale (EDSS), age at onset, mono- or multifocal onset, disease progression and conversion to secondary progression of initially relapsing-remitting MS. For statistical analyses Wilcoxon's signed-rank statistics for categorical differences, t-statistics for continuous variables, McNemar's test for relative frequencies of categories, intra-class correlations for within sibling-pair associations, or Kaplan-Meier analysis for survival analyses were used; all two-sided at the 5% level.

RESULTS

Disease onset was slightly earlier (29.01 vs. 29.44 years, p = 0.0492) and multifocal onset significantly more often (p = 0.0052) in familial than in sporadic MS. Notably, a substantial within sibling-pair correlation for disease progression (rho = 0.40; p = 0.0062) as well as a higher risk for siblings than for controls to convert into secondary progression (0.545 vs. 0.227; p = 0.018) could be observed.

CONCLUSIONS

Familial MS differs from sporadic cases with respect to age at onset, multifocal involvement as first clinical event, and conversion into secondary progression. The progression rate of one out of two affected siblings may act as a predictor for the other sib.

Disease onset in familial and sporadic primary progressive multiple sclerosis

The pathophysiology of primary progressive (PP) multiple sclerosis (MS) involves diffuse axonal degeneration which is believed to start early in the disease process, even before the onset of clinical symptoms. Symptomatic onset then occurs when this process reaches a threshold after which the axonal loss can no longer be compensated. A preliminary study showed that patients with familial PPMS had an earlier clinical onset than patients with sporadic disease, suggesting a hereditary component to the disease process of PPMS. In this study, we combined data from two large, population-based, longitudinal MS databases to investigate disease onset in familial and sporadic PPMS. We examined 411 patients with PPMS. There were no differences in gender distribution or onset symptoms between familial and sporadic PPMS. Patients with familial PPMS were significantly younger at disease onset (n = 84, median age: 37.6 years) than patients with sporadic disease (n = 327, median age: 42.7, p = 0.007). This difference was due to a greater proportion of familial cases with a disease onset before the age of 30 and a smaller proportion with disease onset between 40 and 50 years of age (p = 0.002). Gender had no significant effect on the age at disease onset. Further analyses showed that these findings were unlikely to be due to ascertainment bias towards an earlier diagnosis in familial cases. Our findings suggest a hereditary component to the disease process of PPMS. It would be worthwhile to identify patients with familial PPMS for future research on disease modifying genes in MS.

Immunological basis for the development of tissue inflammation and organ-specific autoimmunity in animal models of multiple sclerosis

Experimental autoimmune encephalomyelitis (EAE) is an animal model for multiple sclerosis (MS) that has shaped our understanding of autoimmune tissue inflammation in the central nervous system (CNS). Major therapeutic approaches to MS have been first validated in EAE. Nevertheless, EAE in all its modifications is not able to recapitulate the full range of clinical and histopathogenic aspects of MS. Furthermore, autoimmune reactions in EAE-prone rodent strains and MS patients may differ in terms of the relative involvement of various subsets of immune cells. However, the role of specific molecules that play a role in skewing the immune response towards pathogenic autoreactivity is very similar in mice and humans. Thus, in this chapter, we will focus on the identification of a novel subset of inflammatory T cells, called Th17 cells, in EAE and their interplay with other immune cells including protective regulatory T cells (T-regs). It is likely that the discovery of Th17 cells and their relationship with T-regs will change our understanding of organ-specific autoimmune diseases in the years to come.

Anticipation of age at onset in familial multiple sclerosis

BACKGROUND AND OBJECTIVE

Anticipation of age at onset in the younger generations is a widely known characteristic of many diseases with genetic inheritance. This study was performed to assess whether there is anticipation of age at onset in younger generations of familial multiple sclerosis (MS) in a Spanish population and to compare clinical characteristics of familial and sporadic MS.

METHODS

We studied a cohort of 1110 patients diagnosed with MS and followed-up in our MS Unit. Patients were considered as familial MS if they had in their family at least one relative of first or second degree diagnosed with MS. Otherwise, patients were considered to have sporadic MS. We compared the age at onset between relatives from different generations, and we also compared the age at onset of familial and sporadic MS.

RESULTS

A lower age at onset in the younger generations was found (median 22 years vs. 30 years, P < 0.001) and a significant lower age at onset of the disease in familial MS comparing to sporadic MS (median 25 years vs. 29 years, P = 0.042).

CONCLUSIONS

There is an anticipation of the age at onset of MS in the younger generations of patients with familial MS. There is also a lower age at onset in familial versus sporadic MS.

Age of onset in concordant twins and other relative pairs with multiple sclerosis

The ages of onset in multiple sclerosis cases span more than 7 decades. Data are presented for affected relative pairs from a Canadian population base of 30,000 multiple sclerosis index cases (1993–2008). The effects of genetic sharing, parent of origin, intergenerational versus collinear differences, and gender on the ages of onset were evaluated in the following concordant pairs: monozygotic twins (n = 29), dizygotic twins (n = 10), siblings (n = 614), first cousins (n = 405), half siblings (n = 29), parent/child (n = 285), and aunt/uncle/niece/nephew (avunculars) (n = 289). Fisher's z test assessed intraclass correlation (r) for ages of onset. Correlations for monozygotic twins, dizygotic twins, full siblings, and first cousins were 0.60, 0.54, 0.20, and 0.10, respectively. Dizygotic twins resembled monozygotic twins more than siblings. The age-of-onset correlation for maternal half siblings (r = 0.37) was higher than that for paternal half siblings (r = 0.26), consistent with other observations suggesting an intrauterine environmental effect on multiple sclerosis risk. Intergenerational comparisons are complicated by substantial increases of multiple sclerosis incidence over time. Genetic loading (familial vs. sporadic cases) did not generally influence the age of onset, but correlation of age of onset in multiple sclerosis relative pairs was proportional to genetic sharing. A maternal parent-of-origin effect on the age of onset in collinear generations was suggested.

Multiple sclerosis: clinical features, pathophysiology, neuroimaging and future therapies

Multiple sclerosis (MS) is a common immune-mediated progressive neurodegenerative disease of the CNS that typically manifests with periods of disease activity followed by intervals of remission. The etiology of MS remains unknown; however, existing evidence indicates that MS is a ‘whole-brain disease’ that is driven by a potent immune response against CNS antigen(s), particularly myelin peptide antigens. The immunopathogenesis of MS includes both the cell- and humorally-mediated arms of the immune system. Genetic and environmental factors play important roles in the development of MS. Application of various neuroimaging techniques to the world of MS have expanded our knowledge concerning its pathogenesis and assist us in the more accurate diagnosis of MS versus its imitators. Current treatments target acute attacks and aim to reduce future clinical relapses. A summary of the potential future therapies for MS is presented.

Mortality in multiple sclerosis: a review

This work was undertaken to evaluate studies on mortality caused by multiple sclerosis (MS), to evaluate if useful inferences can be drawn from survival studies that can be applied to clinical practice. A literature search was carried out to find epidemiological studies on MS prognosis, survival, mortality and causes of death relevant to our aim. The World Health Organization (WHO) reports on worldwide cause-specific mortality were also considered. Studies were evaluated according to the duration of the follow-up study, the year of publication and the methodology used. We evaluated MS survival from a methodological point of view and considered if time trends could be drawn from study results. We conclude that mortality is only slightly higher in MS patients when compared with that in the general population. Mortality is higher particularly for older patients and those with longer disease duration.

Progression in familial and nonfamilial MS

OBJECTIVE

To investigate whether the timing of secondary or primary progression is different between patients with familial and nonfamilial multiple sclerosis (MS).

METHODS

Information on the family history of 313 patients with MS was taken from our prospective hospital-based database. We used Kaplan-Meier analyses and Cox regression models to evaluate differences between familial and nonfamilial MS in several endpoint measures. We investigated the risk of developing secondary progression in all patients with a relapsing-remitting disease onset, the length of the relapsing-remitting phase and age at onset of progression in patients with secondary progressive MS and the age at disease onset in patients with primary progressive MS (PPMS).

RESULTS

Among the primary progressive patients, those with familial MS had a significantly younger age at disease onset than patients with nonfamilial MS (mean 33.04 years versus mean 37.73 years in nonfamilial MS, P = 0.02). There were no significant differences between familial and nonfamilial MS patients in any other investigated measure.

CONCLUSIONS

Familial MS appears related to the time of disease onset in PPMS. Patients with familial PPMS may be an important patient group for future genetic research in MS.

Epidemiology of multiple sclerosis in western Herzegovina

OBJECTIVES

To determine epidemiological rates of multiple sclerosis (MS) in western Herzegovina.

PATIENTS AND METHODS

We analysed data from 81 MS patients (49 females, 32 males) on the prevalence day, 31 December 2003. Patient information was obtained from a search of all available medical records from the period 1994-2003 in the investigated area.

RESULTS

Crude prevalence of MS was 27/100,000 (95% confidence interval (CI) 20-34). Prevalence was highest in the mountainous municipality of Posusje (56/100,000) and lowest in the coastal municipality of Neum (0 incidence). The annual incidence of MS was 1.6/100,000 (95% CI 0-3.3). The female/male ratio of MS was 1.5. The mean age of the patients on prevalence day was 40.0+/-11.6 years, and the mean age at disease onset was 31.0+/-7.1 years. Eight (10%) of the patients had a first-degree relative with MS. The primary progressive (PP) disease course was observed only in females. Visual symptoms were the initial symptom of MS in 6 (7%) of the patients.

CONCLUSIONS

Western Herzegovina is an area of moderate risk for MS, and the distribution of MS in western Herzegovina is heterogeneous. PP-MS occurred only in females, and involvement of the visual pathways as the initial symptom of MS was low.

MSBase: an international, online registry and platform for collaborative outcomes research in multiple sclerosis

Observational cohort studies are a powerful tool to assess the long-term outcome in chronic diseases. This study design has been utilized in local and regional outcome studies in multiple sclerosis (MS) and has yielded invaluable epidemiological information. The World Wide Web now provides an excellent opportunity for an international, collaborative cohort study of MS outcomes. A web platform--MSBase--has been designed to collect prospective data on patients with MS. It is purely observational, enabling participating neurologists to contribute data on diagnosis, treatment and progress, to review anonymous aggregate data and to benchmark their patient population against other patient subsets or the entire dataset. MSBase facilitates collaborative research by allowing the online creation of investigator-initiated regional, national and international substudies. The registry aims to answer epidemiological questions that can only be addressed by prospective assessments of large patient cohorts. The registry is funded through the independent MSBase Foundation, and governed by an International Scientific Advisory Board. The MSBase Foundation commenced operations in July 2004 and since then, 22 neurologists from 11 countries have joined MSBase and are contributing 2400 patients to the total data pool.

Western and Asian features of multiple sclerosis in Mexican Mestizos

OBJECTIVES

The objective of this study was to compare the clinical expression of MS in Mexican Mestizos with that of patients of European or Asian descent; as well as to compare the annual frequency of new cases with that observed in the previous decades.

PATIENTS AND METHODS

All patients with diagnosis of definite MS seen at the National Institute of Neurology and Neurosurgery of Mexico from January 1993 to December 2003 were studied (n=312). Sociodemographic and clinical characteristics were compared with reports of patients from either Western or Asian origin; the long-term disability score was analyzed according to gender, age of onset of MS and the initial symptom.

RESULTS

The clinical expression of MS in Mexican Mestizos shares some characteristics with both, Asian and Western forms of MS indicating that the genetic composition of Mexican Mestizos participates in the clinical expression of the disease. Also, at the prevalence date, the mean age of patients and the duration of the disease were lower in our patients than in MS patients from endemic countries suggesting a true increasing incidence in recent times, rather than only improved case ascertainment.

CONCLUSIONS

Clinical expression of MS in Mexican Mestizos shows the coexistence of some features common in European and in Asian cases.