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Goodin DS, Khankhanian P, Gourraud PA, Vince N. Multiple sclerosis: Exploring the limits and implications of genetic and environmental susceptibility. PLoS One 2023; 18:e0285599. [PMID: 37379505 PMCID: PMC10306391 DOI: 10.1371/journal.pone.0285599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 04/27/2023] [Indexed: 06/30/2023] Open
Abstract
OBJECTIVE To explore and describe the basis and implications of genetic and environmental susceptibility to multiple sclerosis (MS) using the Canadian population-based data. BACKGROUND Certain parameters of MS-epidemiology are directly observable (e.g., the recurrence-risk of MS in siblings and twins, the proportion of women among MS patients, the population-prevalence of MS, and the time-dependent changes in the sex-ratio). By contrast, other parameters can only be inferred from the observed parameters (e.g., the proportion of the population that is "genetically susceptible", the proportion of women among susceptible individuals, the probability that a susceptible individual will experience an environment "sufficient" to cause MS, and if they do, the probability that they will develop the disease). DESIGN/METHODS The "genetically susceptible" subset (G) of the population (Z) is defined to include everyone with any non-zero life-time chance of developing MS under some environmental conditions. The value for each observed and non-observed epidemiological parameter is assigned a "plausible" range. Using both a Cross-sectional Model and a Longitudinal Model, together with established parameter relationships, we explore, iteratively, trillions of potential parameter combinations and determine those combinations (i.e., solutions) that fall within the acceptable range for both the observed and non-observed parameters. RESULTS Both Models and all analyses intersect and converge to demonstrate that probability of genetic-susceptibitly, P(G), is limited to only a fraction of the population {i.e., P(G) ≤ 0.52)} and an even smaller fraction of women {i.e., P(G│F) < 0.32)}. Consequently, most individuals (particularly women) have no chance whatsoever of developing MS, regardless of their environmental exposure. However, for any susceptible individual to develop MS, requires that they also experience a "sufficient" environment. We use the Canadian data to derive, separately, the exponential response-curves for men and women that relate the increasing likelihood of developing MS to an increasing probability that a susceptible individual experiences an environment "sufficient" to cause MS. As the probability of a "sufficient" exposure increases, we define, separately, the limiting probability of developing MS in men (c) and women (d). These Canadian data strongly suggest that: (c < d ≤ 1). If so, this observation establishes both that there must be a "truly" random factor involved in MS pathogenesis and that it is this difference, rather than any difference in genetic or environmental factors, which primarily accounts for the penetrance difference between women and men. CONCLUSIONS The development of MS (in an individual) requires both that they have an appropriate genotype (which is uncommon in the population) and that they have an environmental exposure "sufficient" to cause MS given their genotype. Nevertheless, the two principal findings of this study are that: P(G) ≤ 0.52)} and: (c < d ≤ 1). Threfore, even when the necessary genetic and environmental factors, "sufficient" for MS pathogenesis, co-occur for an individual, they still may or may not develop MS. Consequently, disease pathogenesis, even in this circumstance, seems to involve an important element of chance. Moreover, the conclusion that the macroscopic process of disease development for MS includes a "truly" random element, if replicated (either for MS or for other complex diseases), provides empiric evidence that our universe is non-deterministic.
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Affiliation(s)
- Douglas S. Goodin
- Department of Neurology, San Francisco & the San Francisco VA Medical Center, University of California, San Francisco, San Francisco, California, United States of Ameirca
| | - Pouya Khankhanian
- Kaiser Permanente, Walnut Creek Medical Center, Dublin, California, United States of Ameirca
| | - Pierre-Antoine Gourraud
- Center for Neuro-Engineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of Ameirca
| | - Nicolas Vince
- INSERM, Center for Research in Transplantation and Translational Immunology, UMR 1064, Nantes Université, Nantes, France
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Hogeboom C. Does multiple sclerosis have a zoonotic origin? Correlations with lymphocytic choriomeningitis virus infection. Front Immunol 2023; 14:1217176. [PMID: 37398653 PMCID: PMC10313729 DOI: 10.3389/fimmu.2023.1217176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/06/2023] [Indexed: 07/04/2023] Open
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Ladakis DC, Bhargava P. The Role of Gut Dysbiosis and Potential Approaches to Target the Gut Microbiota in Multiple Sclerosis. CNS Drugs 2023; 37:117-132. [PMID: 36690786 DOI: 10.1007/s40263-023-00986-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/12/2023] [Indexed: 01/25/2023]
Abstract
It has now been established that a perturbation in gut microbiome composition exists in multiple sclerosis (MS) and its interplay with the immune system and brain could potentially contribute to the development of the disease and influence its course. The effects of the gut microbiota on the disease may be mediated by direct interactions between bacteria and immune cells or through interactions of products of bacterial metabolism with immune and CNS cells. In this review article we summarize the ways in which the gut microbiome of people with MS differs from controls and how bacterial metabolites can potentially play a role in MS pathogenesis, and examine approaches to alter the composition of the gut microbiota potentially alleviating gut dysbiosis and impacting the course of MS.
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Affiliation(s)
- Dimitrios C Ladakis
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N Wolfe St, Pathology 627, Baltimore, MD, 21287, USA
| | - Pavan Bhargava
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N Wolfe St, Pathology 627, Baltimore, MD, 21287, USA.
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Trends in the environmental risks associated with earlier onset in multiple sclerosis. Mult Scler Relat Disord 2022; 68:104250. [PMID: 36544313 DOI: 10.1016/j.msard.2022.104250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 09/27/2022] [Accepted: 10/16/2022] [Indexed: 11/11/2022]
Abstract
BACKGROUND Several environmental and lifestyle factors relating to sunlight/vitamin D, body mass index (BMI), and smoking are associated with the risk of developing multiple sclerosis (MS). However, their relation to disease progression, particularly age at symptomatic onset, remains inconsistent, which may be the result of significant changes in human-environment interactions over the last century. This study investigates historical trends in the association between common MS environmental risk factors and age at disease onset. METHODS Using a narrative approach, we evaluated the current literature for published studies assessing the association between vitamin-D, BMI, and tobacco smoking exposures with the risk of early/pediatric-onset MS and direct correlations with age at MS onset using MEDLINE, EMBASE, and Web of Science. Measures were plotted by the average calendar year of disease onset for each cohort to examine trends over time. In total, 25, 9, and 11 articles were identified for vitamin D, BMI, and smoking-related exposures, respectively. RESULTS Higher sun exposure habits and residential solar radiation were associated with older age at onset. On the contrary, two studies observed a negative correlation between age at onset and serum 25-hydroxyvitamin D (25(OH)D) levels. Higher adolescent BMI was generally associated with younger age at onset, although genetic susceptibility for childhood obesity was not significantly associated. Tobacco smoking was associated with later disease onset, despite being a risk factor for MS. Association with age at onset was inflated for more recent studies relating to smoking, while often weaker for serum vitamin D and BMI. CONCLUSION Current findings indicate a likely association between age at onset and environmental risk factors, such as sun exposure, adolescent BMI, and tobacco smoking, in certain populations. However, findings are often inconsistent and assessment of the relationships and potential changes over time require further investigation.
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Gerussi A, Soskic B, Asselta R, Invernizzi P, Gershwin ME. GWAS and autoimmunity: What have we learned and what next. J Autoimmun 2022; 133:102922. [PMID: 36209690 DOI: 10.1016/j.jaut.2022.102922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 12/07/2022]
Abstract
Autoimmune diseases are common conditions characterized by loss of tolerance, female predominance and a remarkable heterogeneity among different populations. Most often they are polygenic and several genetic loci have been linked with the risk of developing autoimmune diseases. However, causal inference is difficult. When the genomic revolution began there were high hopes of translating fast genetic analyses to the bedside but this has proven to be challenging. Nonetheless, over the last decade, fine-mapping strategies have greatly improved; one of the most significant research lines focuses on the in vivo and ex vivo definition of the effect of genetic variants within the target tissues and within specific subpopulations of immune cells that are involved in the disease pathogenesis. This strategy also includes the longitudinal tracking of a large number of immunophenotypes in many individuals to build a large reference atlas for variant characterization. In this review, we discuss the results obtained by GWAS in autoimmune diseases and review recent advances in fine mapping strategies. More importantly, we discuss gaps and future directions.
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Affiliation(s)
- Alessio Gerussi
- Division of Gastroenterology, Center for Autoimmune Liver Diseases, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy; European Reference Network on Hepatological Diseases (ERN RARE-LIVER), San Gerardo Hospital, Monza, Italy.
| | - Blagoje Soskic
- Human Technopole, Viale Rita Levi-Montalcini 1, 20157 Milan, Italy
| | - Rosanna Asselta
- IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy; Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy
| | - Pietro Invernizzi
- Division of Gastroenterology, Center for Autoimmune Liver Diseases, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy; European Reference Network on Hepatological Diseases (ERN RARE-LIVER), San Gerardo Hospital, Monza, Italy
| | - Merrill E Gershwin
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, Davis, CA, United States
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Kearns PKA. Prevention of MS Requires Intervention on the Causes of the Disease: Reconciling Genes, Epigenetics, and Epstein Barr Virus. Front Neurol 2022; 13:817677. [PMID: 35273557 PMCID: PMC8902355 DOI: 10.3389/fneur.2022.817677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/13/2022] [Indexed: 11/28/2022] Open
Abstract
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.
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Affiliation(s)
- Patrick K A Kearns
- Chromatin Lab, MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom.,Anne Rowling Regenerative Neurology Clinic, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,Department of Clinical Neurosciences (Neurology), Royal Infirmary of Edinburgh, NHS Lothian, Edinburgh, United Kingdom
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Genetics and familial distribution of multiple sclerosis: A review. Rev Neurol (Paris) 2022; 178:512-520. [DOI: 10.1016/j.neurol.2021.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/30/2021] [Accepted: 11/04/2021] [Indexed: 11/18/2022]
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Woźniak E, Owczarczyk-Saczonek A, Placek W. Psychological Stress, Mast Cells, and Psoriasis-Is There Any Relationship? Int J Mol Sci 2021; 22:ijms222413252. [PMID: 34948049 PMCID: PMC8705845 DOI: 10.3390/ijms222413252] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 12/06/2021] [Indexed: 12/19/2022] Open
Abstract
Psoriasis vulgaris is a common inflammatory skin disease with still unknown pathogenesis. In recent years, genetic and environmental factors have been mentioned as the main causes. Among environmental factors, many researchers are trying to investigate the role of mental health and its importance in the development of many diseases. In the pathophysiology of psoriasis, the role of the interaction between the nervous, endocrine, and immune systems are often emphasized. So far, no one has clearly indicated where the pathological process begins. One of the hypotheses is that chronic stress influences the formation of hormonal changes (lowering the systemic cortisol level), which favors the processes of autoimmunity. In inflammatory skin conditions, mast cells (MCs) are localized close to blood vessels and peripheral nerves, where they probably play an important role in the response to environmental stimuli and emotional stress. They are usually connected with a fast immune response, not only in allergies but also a protective response to microbial antigens. Among many cells of the immune system, MCs have receptors for the hormones of the hypothalamic-pituitary-adrenal (HPA) axis on their surface. In this review, we will try to take a closer look at the role of MCs in the pathophysiology of psoriasis. This knowledge may give the opportunity to search for therapeutic solutions.
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Stridh P, Kockum I, Huang J. Seasonal variability of serum 25-hydroxyvitamin D on multiple sclerosis onset. Sci Rep 2021; 11:20989. [PMID: 34697348 PMCID: PMC8546079 DOI: 10.1038/s41598-021-00344-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/08/2021] [Indexed: 11/24/2022] Open
Abstract
Vitamin D deficiency is associated with an increased risk of multiple sclerosis (MS). However, its effect on the age of disease onset remains unclear. This study examines the relationship between serum 25-hydroxyvitamin D (25(OH)D) levels and age of first symptom onset among recently diagnosed MS patients. Serum 25(OH)D was measured from forty MS patients sampled near disease onset. After correcting seasonal variability, the association between 25(OH)D levels, along with other clinical measures such as IgG index, and age at MS onset was examined using multivariable linear regression. Serum 25(OH)D was not correlated with age at onset (P > 0.5). We observed bias among previously reported associations between 25(OH)D and MS disease measures resulting from non-random distribution of sampling by season. After correcting for seasonal 25(OH)D and other clinical measures, only CSF IgG index remained significantly associated with age at disease onset (β = − 5.35, P = 0.028). In summary, we observed no association between age at onset and serum 25(OH)D levels but observed a negative correlation with CSF IgG index, although this will require further investigation.
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Affiliation(s)
- Pernilla Stridh
- Center of Molecular Medicine, Karolinska University Hospital, Solna, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Ingrid Kockum
- Center of Molecular Medicine, Karolinska University Hospital, Solna, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Jesse Huang
- Center of Molecular Medicine, Karolinska University Hospital, Solna, Sweden. .,Department of Clinical Neuroscience, Karolinska Institutet, Solna, Sweden.
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Epigenetic Changes Induced by Maternal Factors during Fetal Life: Implication for Type 1 Diabetes. Genes (Basel) 2021; 12:genes12060887. [PMID: 34201206 PMCID: PMC8227197 DOI: 10.3390/genes12060887] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 02/07/2023] Open
Abstract
Organ-specific autoimmune diseases, such as type 1 diabetes, are believed to result from T-cell-mediated damage of the target tissue. The immune-mediated tissue injury, in turn, is known to depend on complex interactions between genetic and environmental factors. Nevertheless, the mechanisms whereby environmental factors contribute to the pathogenesis of autoimmune diseases remain elusive and represent a major untapped target to develop novel strategies for disease prevention. Given the impact of the early environment on the developing immune system, epigenetic changes induced by maternal factors during fetal life have been linked to a likelihood of developing an autoimmune disease later in life. In humans, DNA methylation is the epigenetic mechanism most extensively investigated. This review provides an overview of the critical role of DNA methylation changes induced by prenatal maternal conditions contributing to the increased risk of immune-mediated diseases on the offspring, with a particular focus on T1D. A deeper understanding of epigenetic alterations induced by environmental stressors during fetal life may be pivotal for developing targeted prevention strategies of type 1 diabetes by modifying the maternal environment.
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Abstract
Many groundbreaking advances have occurred in the field of multiple sclerosis since this series last reviewed the disorder in 2014. The U.S. Food and Drug Administration has approved 7 new medications for relapsing-remitting multiple sclerosis and approved the first medication for primary progressive multiple sclerosis. The McDonald criteria for diagnosing multiple sclerosis were updated in 2017. New blood tests can now differentiate patients with multiple sclerosis from those with neuromyelitis optica spectrum disorder, and 3 new medications have been approved specifically for the latter disorder. Also, new medications for treating the symptoms of multiple sclerosis have been introduced.
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Goodin DS, Khankhanian P, Gourraud PA, Vince N. The nature of genetic and environmental susceptibility to multiple sclerosis. PLoS One 2021; 16:e0246157. [PMID: 33750973 PMCID: PMC7984655 DOI: 10.1371/journal.pone.0246157] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 01/15/2021] [Indexed: 01/04/2023] Open
Abstract
OBJECTIVE To understand the nature of genetic and environmental susceptibility to multiple sclerosis (MS) and, by extension, susceptibility to other complex genetic diseases. BACKGROUND Certain basic epidemiological parameters of MS (e.g., population-prevalence of MS, recurrence-risks for MS in siblings and twins, proportion of women among MS patients, and the time-dependent changes in the sex-ratio) are well-established. In addition, more than 233 genetic-loci have now been identified as being unequivocally MS-associated, including 32 loci within the major histocompatibility complex (MHC), and one locus on the X chromosome. Despite this recent explosion in genetic associations, however, the association of MS with the HLA-DRB1*15:01~HLA-DQB1*06:02~a1 (H+) haplotype has been known for decades. DESIGN/METHODS We define the "genetically-susceptible" subset (G) to include everyone with any non-zero life-time chance of developing MS. Individuals who have no chance of developing MS, regardless of their environmental experiences, belong to the mutually exclusive "non-susceptible" subset (G-). Using these well-established epidemiological parameters, we analyze, mathematically, the implications that these observations have regarding the genetic-susceptibility to MS. In addition, we use the sex-ratio change (observed over a 35-year interval in Canada), to derive the relationship between MS-probability and an increasing likelihood of a sufficient environmental exposure. RESULTS We demonstrate that genetic-susceptibitly is confined to less than 7.3% of populations throughout Europe and North America. Consequently, more than 92.7% of individuals in these populations have no chance whatsoever of developing MS, regardless of their environmental experiences. Even among carriers of the HLA-DRB1*15:01~HLA-DQB1*06:02~a1 haplotype, far fewer than 32% can possibly be members the (G) subset. Also, despite the current preponderance of women among MS patients, women are less likely to be in the susceptible (G) subset and have a higher environmental threshold for developing MS compared to men. Nevertheless, the penetrance of MS in susceptible women is considerably greater than it is in men. Moreover, the response-curves for MS-probability in susceptible individuals increases with an increasing likelihood of a sufficient environmental exposure, especially among women. However, these environmental response-curves plateau at under 50% for women and at a significantly lower level for men. CONCLUSIONS The pathogenesis of MS requires both a genetic predisposition and a suitable environmental exposure. Nevertheless, genetic-susceptibility is rare in the population (< 7.3%) and requires specific combinations of non-additive genetic risk-factors. For example, only a minority of carriers of the HLA-DRB1*15:01~HLA-DQB1*06:02~a1 haplotype are even in the (G) subset and, thus, genetic-susceptibility to MS in these carriers must result from the combined effect this haplotype together with the effects of certain other (as yet, unidentified) genetic factors. By itself, this haplotype poses no MS-risk. By contrast, a sufficient environmental exposure (however many events are involved, whenever these events need to act, and whatever these events might be) is common, currently occurring in, at least, 76% of susceptible individuals. In addition, the fact that environmental response-curves plateau well below 50% (especially in men), indicates that disease pathogenesis is partly stochastic. By extension, other diseases, for which monozygotic-twin recurrence-risks greatly exceed the disease-prevalence (e.g., rheumatoid arthritis, diabetes, and celiac disease), must have a similar genetic basis.
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Affiliation(s)
- Douglas S. Goodin
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States of America
| | - Pouya Khankhanian
- Center for Neuro-Engineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Pierre-Antoine Gourraud
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States of America
- Centre de Recherche en Transplantation et Immunologie UMR 1064, INSERM, Université de Nantes, Nantes, France
- Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France
| | - Nicolas Vince
- Centre de Recherche en Transplantation et Immunologie UMR 1064, INSERM, Université de Nantes, Nantes, France
- Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France
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AlJumah M, Otaibi HA, Al Towaijri G, Hassan A, Kareem A, Kalakatawi M, Alrajeh S, Al Mejally M, Algahtani H, Almubarak A, Alawi S, Qureshi S, Al Malik Y, El-Metwally A, Shami S, Ishak S, Bunyan R. Familial aggregation of multiple sclerosis: Results from the national registry of the disease in Saudi Arabia. Mult Scler J Exp Transl Clin 2020; 6:2055217320960499. [PMID: 33110617 PMCID: PMC7556172 DOI: 10.1177/2055217320960499] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/05/2020] [Accepted: 08/25/2020] [Indexed: 12/30/2022] Open
Abstract
Background Multiple Sclerosis (MS) is a chronic CNS inflammatory disease commonly affecting young adults. Both genetics and environmental factors have been reported to have a role in pathophysiology of the disease. Objective This article aims to report familial nature and aspects of MS in Saudi Arabia. Method The study utilized data collected by the National Saudi MS Registry between 2015 and 2018; especially data relevant to the familial history of MS. SPSS 22 was used for all analysis and reporting. Statistical significance was set at p-value < 0.05. Results The registry included 20 hospitals and a total of 2516 patients from the different regions of Saudi Arabia with median age 32.00 (Range: 11-63) and 66.5% being female. About 12.8% of all registered patients reported a family history of MS (95%CI: 11.2-13.9). Reported parental consanguinity was significantly higher among patients with family history (FMS) (56.3%) compared to non-FMS patients (27.9%). 42.53% of FMS patients reported having siblings affected with MS (95%CI: 37.01-48.21), with more female siblings affected than males (63.4% vs 36.6% respectively). Conclusion Our Findings suggested that FMS was less prevalent than what was reported previously; however, parental consanguinity was significantly more prevalent among FMS patients than non-FMS. Our findings were in line with those reported in recent studies in the region, but lower than those reported by western countries indicating that increasing prevalence of MS in Saudi Arabia could be multifactorial and other environmental factors should be considered for understanding this recent rise in the prevalence of MS in Saudi Arabia.
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Affiliation(s)
- Mohammed AlJumah
- Neurology Department, King Fahd Medical City (KFMC), MOH, Riyadh, Saudi Arabia
| | - Hessa Al Otaibi
- Neurology Department, King Fahd General Hospital-Jeddah, Jeddah, Saudi Arabia
| | - Ghada Al Towaijri
- Neurology Department, King Fahd Medical City (KFMC), MOH, Riyadh, Saudi Arabia
| | - Ahmed Hassan
- Neurology Department, King Faisal Specialist Hospital & Research Center, Jeddah, Saudi Arabia
| | - Abid Kareem
- Neurology Department, King Fahd General Hospital-Al-Madinah, Madinah, Saudi Arabia
| | | | - Saad Alrajeh
- Neurology Department, Dr. Sulaiman Al Habib Hospital-Olaya Branch, Riyadh, Saudi Arabia
| | - Mousa Al Mejally
- Neurology Department, Heraa General Hospital, Makkah, Saudi Arabia
| | - Hussein Algahtani
- Neurology Department, King Abdul-Aziz Medical City (National Guard Health Affairs), Jeddah, Saudi Arabia
| | - Ali Almubarak
- Neurology Department, Qatif Central Hospital, Qatif, Saudi Arabia
| | - Sadaga Alawi
- Neurology Department, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Shireen Qureshi
- Neurology Department, Johns Hopkins Aramco Healthcare Company (JHAH), Dhahran, Saudi Arabia
| | - Yaser Al Malik
- Neurology Department, King Saud bin Abdulaziz University For Health Sciences, Riyadh, Saudi Arabia
| | - Ashraf El-Metwally
- King Saud bin Abdulaziz University For Health Sciences, Riyadh, Saudi Arabia
| | - Sahar Shami
- King Fahd Specialist Hospital (KFSH)-Dammam, Dammam, Saudi Arabia
| | - Samah Ishak
- Itkan Health Consulting, Riyadh, Saudi Arabia
| | - Reem Bunyan
- King Fahd Specialist Hospital (KFSH)-Dammam, Dammam, Saudi Arabia
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Lam T, VoPham T, Munger KL, Laden F, Hart JE. Long-term effects of latitude, ambient temperature, and ultraviolet radiation on the incidence of multiple sclerosis in two cohorts of US women. Environ Epidemiol 2020; 4:e0105. [PMID: 32903352 PMCID: PMC7431017 DOI: 10.1097/ee9.0000000000000105] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 06/16/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Differences in multiple sclerosis (MS) risk by latitude have been observed worldwide; however, the exposures driving these associations are unknown. Ultraviolet radiation (UV) has been explored as a risk factor, and ambient temperature has been correlated with disease progression. However, no study has examined the impact of all three exposures. We examined the association between these exposures and incidence of MS within two nationwide prospective cohorts of women, the Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII). METHODS Both cohorts were followed with biennial questionnaires to ascertain new diagnoses and risk factors. Time-varying exposures to latitude, cumulative average July temperature (°C), and cumulative average July erythemal UV (mW/m2) were predicted at each participant's biennially updated residential addresses. Using Cox proportional hazards models adjusted for MS risk factors, we calculated hazard ratios (HR) and 95% confidence intervals (CIs) within each cohort and pooled via meta-analyses. RESULTS In multivariable models, there were suggestions that decreasing latitude (meta-analysis multivariable-adjusted HR = 0.72; 95% CI 0.55, 0.94 for women living <35.73° compared with those ≥42.15°, P-for-trend = 0.007) and increasing cumulative average July temperature (meta-analysis multivariable-adjusted HR = 0.81; 95% CI 0.72, 0.91 for each interquartile range increase [3.91°]) were associated with decreasing risk of MS. There was no evidence of heterogeneity between cohorts. We did not observe consistent associations with cumulative average UV. CONCLUSION Our results suggest that adult exposures to decreasing latitude and increasing temperature, but not UV, were associated with reduced MS risk in these two cohorts of women. Studies of MS incidence may want to consider temperature as a risk factor.
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Affiliation(s)
- Thao Lam
- Graduate School of Life Sciences, Utrecht University, Utrecht, the Netherlands
| | - Trang VoPham
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
- Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, MA, USA
- Epidemiology Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Kassandra L. Munger
- Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Francine Laden
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
- Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, MA, USA
- Department of Environmental Health, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Jaime E. Hart
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
- Department of Environmental Health, Harvard TH Chan School of Public Health, Boston, MA, USA
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15
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Buscarinu MC, Fornasiero A, Ferraldeschi M, Romano S, Reniè R, Morena E, Romano C, Pellicciari G, Landi AC, Fagnani C, Salvetti M, Ristori G. Disentangling the molecular mechanisms of multiple sclerosis: The contribution of twin studies. Neurosci Biobehav Rev 2020; 111:194-198. [PMID: 31978439 DOI: 10.1016/j.neubiorev.2020.01.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 12/12/2019] [Accepted: 01/20/2020] [Indexed: 02/05/2023]
Abstract
Twin studies of disease concordance are useful to weight the relative contribution of genetic and environmental factors to the cause of common complex disorders. In multiple sclerosis (MS) different twinning rates from geographic areas at different prevalence suggested that heritable and non-heritable factors contribute in different proportions and ways to MS risk in diverse populations. This concept prompted genome-wide association studies, and the implementation of the co-twin control design, that allows stringent experimental approaches in MS-discordant identical pairs, controlling for genetic influences and many other known and unknown factors. The co-twin control design provided important clues on MS molecular model. These studies will be reviewed, focusing on those showing significant differences between affected and healthy co-twins. In some cases, differences that emerged in non-twin patients compared to matched controls were not confirmed in identical MS-discordant pairs, suggesting an 'MS subclinical trait'. Early patterns of magnetic resonance imaging and predictive biomarkers that characterize 'healthy' co-twins may be useful for the identification of a prodromal reversible phase of the disease.
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Affiliation(s)
- M C Buscarinu
- Department of Neurosciences, Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Centre for Experimental Neurological Therapies (CENTERS), Sapienza University, Rome, Italy
| | - A Fornasiero
- Department of Neurosciences, Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Centre for Experimental Neurological Therapies (CENTERS), Sapienza University, Rome, Italy
| | - M Ferraldeschi
- Department of Neurology and Psychiatry, Sapienza University, Rome, Italy
| | - S Romano
- Department of Neurosciences, Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Centre for Experimental Neurological Therapies (CENTERS), Sapienza University, Rome, Italy
| | - R Reniè
- Sapienza University, Rome, Italy
| | - E Morena
- Sapienza University, Rome, Italy
| | - C Romano
- Sapienza University, Rome, Italy
| | | | | | - C Fagnani
- Centro di Riferimento per le Scienze Comportamentali e la Salute Mentale, Istituto Superiore di Sanità, Italy
| | - M Salvetti
- Department of Neurosciences, Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Centre for Experimental Neurological Therapies (CENTERS), Sapienza University, Rome, Italy; IRCCS Istituto Neurologico Mediterraneo (INM) Neuromed, Pozzilli, Italy.
| | - G Ristori
- Department of Neurosciences, Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Centre for Experimental Neurological Therapies (CENTERS), Sapienza University, Rome, Italy.
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16
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Eskandarieh S, Sahraiain MA, Molazadeh N, Moghadasi AN. Pediatric multiple sclerosis and its familial recurrence: A population based study (1999-2017). Mult Scler Relat Disord 2019; 36:101377. [PMID: 31473489 DOI: 10.1016/j.msard.2019.101377] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 07/20/2019] [Accepted: 08/26/2019] [Indexed: 01/02/2023]
Abstract
BACKGROUND The Pediatric onset multiple sclerosis (POMS) prevalence is increasing worldwide accounting for around 3 to 10% of MS cases. The risk of POMS is supposed to reflect a complex interaction between environmental and genetic risk factors that may occur during the childhood, adolescent, or post-pubertal years. OBJECTIVE The present study aimed at estimating the prevalence of POMS and assessing the epidemiology of familial recurrence of POMS in Tehran. METHOD A retrospective population based cross-sectional study was designed from 1999 to 2017. The baseline characteristic information was collected from MS patient's ≤18 years old (y/o). Pearson's chi-square test and logistic regression were used to analyze the relationship among variables and estimate the odds ratio (OR) via SPSS software, version 23. RESULTS A total of 1937 POMS patients (77.80% female and 22.20% male patients) participated in the study. The point prevalence of POMS was 16.20 per 100,000 populations in 2017. Mean age at disease onset was 15.96 ± 2.28 y/o. The female to male ratio was 2.02:1 in pre-pubertal cases (3-12 y/o), but it increased to 3.69:1 in 13-18 y/o age groups (P value = 0.001, OR = 1.82; 95% CI = 1.27-2.26). There were 288 (14.9%) cases with positive familial history of MS. The strongest association between MS risk and positive familial history was observed in second degree relatives who presented MS (P value = 0.046, OR = 1.74; 95%CI = 1.01-3.01). A significant association was observed among maternal second degree relatives with POMS (P value = 0.018, OR = 2.27; 95%CI = 1.15-4.47). CONCLUSION In comparison to other large studies, the prevalence of POMS was high in the data collected from Tehran. POMS risk is higher among females and the sex ratio increases after puberty. We found a significant association between POMS risk and familial history in maternal second degree relatives. Further studies of POMS epidemiology might yield greater understanding of the natural history of this disease.
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Affiliation(s)
- Sharareh Eskandarieh
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mohammad Ali Sahraiain
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Negar Molazadeh
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Abdorreza Naser Moghadasi
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
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17
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Surace AEA, Hedrich CM. The Role of Epigenetics in Autoimmune/Inflammatory Disease. Front Immunol 2019; 10:1525. [PMID: 31333659 PMCID: PMC6620790 DOI: 10.3389/fimmu.2019.01525] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/18/2019] [Indexed: 12/21/2022] Open
Abstract
Historically, systemic self-inflammatory conditions were classified as either autoinflammatory and caused by the innate immune system or autoimmune and driven by adaptive immune responses. However, it became clear that reality is much more complex and that autoimmune/inflammatory conditions range along an “inflammatory spectrum” with primarily autoinflammatory vs. autoimmune conditions resembling extremes at either end. Epigenetic modifications influence gene expression and alter cellular functions without modifying the genomic sequence. Methylation of CpG DNA dinucleotides and/or their hydroxymethylation, post-translational modifications to amino termini of histone proteins, and non-coding RNA expression are main epigenetic events. The pathophysiology of autoimmune/inflammatory diseases has been closely linked with disease causing gene mutations (rare) or a combination of genetic susceptibility and epigenetic modifications arising from exposure to the environment (more common). Over recent years, progress has been made in understanding molecular mechanisms involved in systemic inflammation and the contribution of innate and adaptive immune responses. Epigenetic events have been identified as (i) central pathophysiological factors in addition to genetic disease predisposition and (ii) as co-factors determining clinical pictures and outcomes in individuals with monogenic disease. Thus, a complete understanding of epigenetic contributors to autoimmune/inflammatory disease will result in approaches to predict individual disease outcomes and the introduction of effective, target-directed, and tolerable therapies. Here, we summarize recent findings that signify the importance of epigenetic modifications in autoimmune/inflammatory disorders along the inflammatory spectrum choosing three examples: the autoinflammatory bone condition chronic nonbacterial osteomyelitis (CNO), the “mixed pattern” disorder psoriasis, and the autoimmune disease systemic lupus erythematosus (SLE).
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Affiliation(s)
- Anna Elisa Andrea Surace
- Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Christian M Hedrich
- Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom.,Department of Paediatric Rheumatology, Alder Hey Children's NHS Foundation Trust Hospital, Liverpool, United Kingdom.,Pädiatrische Rheumatologie, Klinik und Poliklinik für Kinder- und Jugendmedizin, Universitätsklinikum Carl Gustav Carus, TU Dresden, Dresden, Germany
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18
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Abstract
A broad scientific consensus has emerged linking multiple sclerosis (MS) risk to multiple independent and interacting DNA variants that are relatively frequent in the population and act in concert with environmental exposures. The multifactorial, polygenic model of heritability provided the rationale and impetus to pursue genome-wide association studies (GWAS), which have been highly successful in uncovering genetic variants influencing susceptibility. Over 200 loci have been firmly associated with MS susceptibility. The main association signal genome-wide maps to the major histocompatibility complex ( MHC) gene cluster in chromosome 6p21. This association has been observed across all populations studied. However, a significant proportion of MS heritability remains unexplained. Decoding the genetics of MS represents a long-standing and important research goal in this disease, as the demonstration of even modest functional genomic effects on risk or the course of MS is likely to reveal fundamental disease mechanisms and possibly yield new therapeutic opportunities.
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Affiliation(s)
- Ester Canto
- Department of Neurology, University of California-San Francisco, San Francisco, CA, USA
| | - Jorge R Oksenberg
- Department of Neurology, University of California-San Francisco, San Francisco, CA, USA
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Greenig M. HERVs, immunity, and autoimmunity: understanding the connection. PeerJ 2019; 7:e6711. [PMID: 30984482 PMCID: PMC6452852 DOI: 10.7717/peerj.6711] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 02/28/2019] [Indexed: 12/30/2022] Open
Abstract
Since their discovery in the 1960s, further investigation into endogenous retroviruses (ERVs) has challenged the conventional view of viral sequences as exclusively parasitic elements. Once presumed to be a group of passive genetic relics, it is becoming increasingly clear that this view of ERVs, while generally accurate, is incorrect in many specific cases. Research has identified ERV genes that appear to be co-opted by their mammalian hosts, but the biological function of ERV elements in humans remains a controversial subject. One area that has attracted some attention in this domain is the role of co-opted ERV elements in mammalian immune systems. The relationship between ERVs and human autoimmune diseases has also been investigated, but has historically been treated as a separate topic. This review will summarize the current evidence concerning the phenotypic significance of ERVs, both in the healthy immune system and in manifestations of autoimmunity. Furthermore, it will evaluate the relationship between these fields of study, and propose previously-unexplored molecular mechanisms through which human endogenous retroviruses might contribute to certain autoimmune pathologies. Investigation into these novel mechanisms could further our understanding of the molecular basis of autoimmune disease, and may one day provide new targets for treatment.
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Affiliation(s)
- Matthew Greenig
- Department of Life Sciences, Imperial College London, London, United Kingdom
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20
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Vitamin D in Neurological Diseases: A Rationale for a Pathogenic Impact. Int J Mol Sci 2018; 19:ijms19082245. [PMID: 30065237 PMCID: PMC6121649 DOI: 10.3390/ijms19082245] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 12/22/2022] Open
Abstract
It is widely known that vitamin D receptors have been found in neurons and glial cells, and their highest expression is in the hippocampus, hypothalamus, thalamus and subcortical grey nuclei, and substantia nigra. Vitamin D helps the regulation of neurotrophin, neural differentiation, and maturation, through the control operation of growing factors synthesis (i.e., neural growth factor [NGF] and glial cell line-derived growth factor (GDNF), the trafficking of the septohippocampal pathway, and the control of the synthesis process of different neuromodulators (such as acetylcholine [Ach], dopamine [DA], and gamma-aminobutyric [GABA]). Based on these assumptions, we have written this review to summarize the potential role of vitamin D in neurological pathologies. This work could be titanic and the results might have been very fuzzy and even incoherent had we not conjectured to taper our first intentions and devoted our interests towards three mainstreams, demyelinating pathologies, vascular syndromes, and neurodegeneration. As a result of the lack of useful therapeutic options, apart from the disease-modifying strategies, the role of different risk factors should be investigated in neurology, as their correction may lead to the improvement of the cerebral conditions. We have explored the relationships between the gene-environmental influence and long-term vitamin D deficiency, as a risk factor for the development of different types of neurological disorders, along with the role and the rationale of therapeutic trials with vitamin D implementation.
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21
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Kearns PKA, Casey HA, Leach JP. Hypothesis: Multiple sclerosis is caused by three-hits, strictly in order, in genetically susceptible persons. Mult Scler Relat Disord 2018; 24:157-174. [PMID: 30015080 DOI: 10.1016/j.msard.2018.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/25/2018] [Accepted: 06/18/2018] [Indexed: 12/15/2022]
Abstract
Multiple Sclerosis is a chronic, progressive and debilitating neurological disease which, despite extensive study for over 100 years, remains of enigmatic aetiology. Drawn from the epidemiological evidence, there exists a consensus that there are environmental (possibly infectious) factors that contribute to disease pathogenesis that have not yet been fully elucidated. Here we propose a three-tiered hypothesis: 1) a clinic-epidemiological model of multiple sclerosis as a rare late complication of two sequential infections (with the temporal sequence of infections being important); 2) a proposal that the first event is helminthic infection with Enterobius Vermicularis, and the second is Epstein Barr Virus infection; and 3) a proposal for a testable biological mechanism, involving T-Cell exhaustion for Epstein-Barr Virus protein LMP2A. We believe that this model satisfies some of the as-yet unexplained features of multiple sclerosis epidemiology, is consistent with the clinical and neuropathological features of the disease and is potentially testable by experiment. This model may be generalizable to other autoimmune diseases.
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Increasing prevalence of familial recurrence of multiple sclerosis in Iran: a population based study of Tehran registry 1999-2015. BMC Neurol 2018; 18:15. [PMID: 29415659 PMCID: PMC5804012 DOI: 10.1186/s12883-018-1019-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 01/29/2018] [Indexed: 11/10/2022] Open
Abstract
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.
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Poutiainen P, Jaronen M, Quintana FJ, Brownell AL. Precision Medicine in Multiple Sclerosis: Future of PET Imaging of Inflammation and Reactive Astrocytes. Front Mol Neurosci 2016; 9:85. [PMID: 27695400 PMCID: PMC5023680 DOI: 10.3389/fnmol.2016.00085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 08/30/2016] [Indexed: 12/29/2022] Open
Abstract
Non-invasive molecular imaging techniques can enhance diagnosis to achieve successful treatment, as well as reveal underlying pathogenic mechanisms in disorders such as multiple sclerosis (MS). The cooperation of advanced multimodal imaging techniques and increased knowledge of the MS disease mechanism allows both monitoring of neuronal network and therapeutic outcome as well as the tools to discover novel therapeutic targets. Diverse imaging modalities provide reliable diagnostic and prognostic platforms to better achieve precision medicine. Traditionally, magnetic resonance imaging (MRI) has been considered the golden standard in MS research and diagnosis. However, positron emission tomography (PET) imaging can provide functional information of molecular biology in detail even prior to anatomic changes, allowing close follow up of disease progression and treatment response. The recent findings support three major neuroinflammation components in MS: astrogliosis, cytokine elevation, and significant changes in specific proteins, which offer a great variety of specific targets for imaging purposes. Regardless of the fact that imaging of astrocyte function is still a young field and in need for development of suitable imaging ligands, recent studies have shown that inflammation and astrocyte activation are related to progression of MS. MS is a complex disease, which requires understanding of disease mechanisms for successful treatment. PET is a precise non-invasive imaging method for biochemical functions and has potential to enhance early and accurate diagnosis for precision therapy of MS. In this review we focus on modulation of different receptor systems and inflammatory aspect of MS, especially on activation of glial cells, and summarize the recent findings of PET imaging in MS and present the most potent targets for new biomarkers with the main focus on experimental MS research.
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Affiliation(s)
- Pekka Poutiainen
- Athinoula A Martinos Biomedical Imaging Center, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA, USA
| | - Merja Jaronen
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA, USA
| | - Francisco J. Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA, USA
| | - Anna-Liisa Brownell
- Athinoula A Martinos Biomedical Imaging Center, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA, USA
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24
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Goodin DS. The nature of genetic susceptibility to multiple sclerosis: constraining the possibilities. BMC Neurol 2016; 16:56. [PMID: 27117889 PMCID: PMC4847201 DOI: 10.1186/s12883-016-0575-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 04/14/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Epidemiological observations regarding certain population-wide parameters (e.g., disease-prevalence, recurrence-risk in relatives, gender predilections, and the distribution of common genetic-variants) place important constraints on the possibilities for the genetic-basis underlying susceptibility to multiple sclerosis (MS). METHODS Using very broad range-estimates for the different population-wide epidemiological parameters, a mathematical model can help elucidate the nature and the magnitude of these constraints. RESULTS For MS no more than 8.5 % of the population can possibly be in the "genetically-susceptible" subset (defined as having a life-time MS-probability at least as high as the overall population average). Indeed, the expected MS-probability for this subset is more than 12 times that for every other person of the population who is not in this subset. Moreover, provided that those genetically susceptible persons (genotypes), who carry the well-established MS susceptibility allele (DRB1*1501), are equally or more likely to get MS than those susceptible persons, who don't carry this allele, then at least 84 % of MS-cases must come from this "genetically susceptible" subset. Finally, because men, compared to women, are at least as likely (and possibly more likely) to be susceptible, it can be demonstrated that women are more responsive to the environmental factors that are involved in MS-pathogenesis (whatever these are) and, thus, susceptible women are more likely actually to develop MS than susceptible men. Finally, in contrast to genetic susceptibility, more than 70 % of men (and likely also women) must have an environmental experience (including all of the necessary factors), which is sufficient to produce MS in a susceptible individual. CONCLUSIONS As a result, because of these constraints, it is possible to distinguish two classes of persons, indicating either that MS can be caused by two fundamentally different pathophysiological mechanisms or that the large majority of the population is at no risk of the developing this disease regardless of their environmental experience. Moreover, although environmental-factors would play a critical role in both mechanisms (if both exist), there is no reason to expect that these factors are the same (or even similar) between the two.
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Affiliation(s)
- Douglas S Goodin
- Department of Neurology, UCSF MS Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite #221D, San Francisco, CA, 94158, USA.
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25
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Goodin DS. The epidemiology of multiple sclerosis: insights to a causal cascade. HANDBOOK OF CLINICAL NEUROLOGY 2016; 138:173-206. [PMID: 27637959 DOI: 10.1016/b978-0-12-802973-2.00011-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
MS-pathogenesis involves both genetic-susceptibility and environmental determinants. Three (or more) sequential environmental-factors are implicated. The first acts near birth, the second acts during childhood/adolescence, and the third acts subsequently. Two candidate factors (vitamin D deficiency and Epstein-Barr viral infection) seem particularly well-suited to the first two environmental-events but other factors (e.g., obesity and smoking behavior) seem also to be involved in the causal scheme. MS-pathogenesis can be modeled by incorporating both the environmental and genetic-factors into a causal scheme, which can then help to explain some of the changes in MS-epidemiology (e.g., increasing disease-prevalence, changing sex-ratio, and regional-variations in monozygotic-twin-concordance-rates), which have been taking place recently. This model suggests that genetic-susceptibility is overwhelmingly the most important determinant of MS and that, at least, 92.5% of individuals (and likely much more) are, essentially, incapable of developing MS, regardless of their specific environmental-exposures. Nevertheless, the genetics is complex and the contribution of any specific gene to MS-susceptibility seems to be quite modest. Thus, even for the DRB1*1501 allele (the strongest known MS-susceptibility marker), most carriers are not in the genetically-susceptible group. Moreover, 45-50% of individuals with MS lack this allele entirely and some of the haplotypes that carry this allele don't also confer any disease-risk. Finally, because the prevalence of genetic-susceptibility seems to be so similar throughout North America and Europe, and despite the crucial importance of a person's genetic make-up to disease pathogenesis, it is the environmental-factors, which largely responsible for the observed regional variations in disease-characteristics. Thus, despite MS being more common in women, men are more likely to be genetically-susceptible. This apparent paradox seems to relate to the fact that women are much more responsive than men to the recent changes in environmental-exposure (whatever these have been). These gender-differences may help to explain changes in the sex-ratio and the increasing disease-prevalence, which have both been observed recently. The potential importance of these conclusions regarding the role of environment in MS-pathogenesis is that they open the door to the possibility of pursuing strategies for primary primary disease prevention in the future.
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Affiliation(s)
- D S Goodin
- Multiple Sclerosis Center at the University of California, San Francisco, San Francisco, CA, USA.
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26
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Affiliation(s)
- Douglas S. Goodin
- MS Center at the University of California, San Francisco; San Francisco CA USA
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27
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Peptide motif analysis predicts lymphocytic choriomeningitis virus as trigger for multiple sclerosis. Mol Immunol 2015; 67:625-35. [DOI: 10.1016/j.molimm.2015.07.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 07/31/2015] [Indexed: 01/08/2023]
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28
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Fagnani C, Neale MC, Nisticò L, Stazi MA, Ricigliano VA, Buscarinu MC, Salvetti M, Ristori G. Twin studies in multiple sclerosis: A meta-estimation of heritability and environmentality. Mult Scler 2015; 21:1404-13. [PMID: 25583848 DOI: 10.1177/1352458514564492] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/16/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND Most twin studies of multiple sclerosis (MS) are inconclusive regarding the impact of genes and environment on disease susceptibility. In particular, high uncertainty exists about whether shared environmental factors are aetiologically relevant. OBJECTIVE To disentangle, with a reasonable degree of confidence, the relative contributions of heritability and of shared and unique environmental components of MS susceptibility. METHODS We performed a meta-analysis of previous twin studies. After a MEDLINE search, we selected eight twin studies in France, UK, Canada, Denmark, North America, Italy, Finland and Sweden. We conducted a biometric multi-group analysis under the liability-threshold model, by taking account of the study-specific ascertainment strategies and the population-specific prevalence rates of MS. RESULTS The meta-analytic estimates of tetrachoric correlations were 0.71 (95% confidence interval (CI): 0.67-0.74) in monozygotic pairs and 0.46 (95% CI: 0.41-0.50) in dizygotic pairs. The biometric multi-group model provided meta-analytic estimates of 0.50 (95% CI: 0.39-0.61) for heritability, 0.21 (95% CI: 0.11-0.30) for shared environmental component and 0.29 (95% CI: 0.26-0.33) for unique environmental component. CONCLUSION Our results support the continuing efforts to identify unknown genetic factors that fill the gap of 'missing heritability'; moreover, a 'missing environmentality' deserves future investigations into the role of non-heritable components that act as both shared and individual-specific exposures.
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Affiliation(s)
- Corrado Fagnani
- National Centre for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, Rome, Italy
| | - Michael C Neale
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, USA
| | - Lorenza Nisticò
- National Centre for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, Rome, Italy
| | - Maria A Stazi
- National Centre for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, Rome, Italy
| | - Vito A Ricigliano
- Centre for Experimental Neurological Therapies (CENTERS), Neurology and Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), 'Sapienza' University of Rome, Italy
| | - Maria C Buscarinu
- Centre for Experimental Neurological Therapies (CENTERS), Neurology and Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), 'Sapienza' University of Rome, Italy
| | - Marco Salvetti
- Centre for Experimental Neurological Therapies (CENTERS), Neurology and Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), 'Sapienza' University of Rome, Italy
| | - Giovanni Ristori
- Centre for Experimental Neurological Therapies (CENTERS), Neurology and Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), 'Sapienza' University of Rome, Italy
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Boullerne AI, Skias D, Hartman EM, Testai FD, Kalinin S, Polak PE, Feinstein DL. A single-nucleotide polymorphism in serine-threonine kinase 11, the gene encoding liver kinase B1, is a risk factor for multiple sclerosis. ASN Neuro 2015; 7:1759091415568914. [PMID: 25694554 PMCID: PMC4342367 DOI: 10.1177/1759091415568914] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
We identified a family in which five siblings were diagnosed with multiple sclerosis (MS) or clinically isolated syndrome. Several women in the maternal lineage have comorbidities typically associated with Peutz Jeghers Syndrome, a rare autosomal-dominant disease caused by mutations in the serine-threonine-kinase 11 (STK11) gene, which encodes liver kinase B1. Sequence analysis of DNA from one sibling identified a single-nucleotide polymorphism (SNP) within STK11 intron 5. This SNP (dbSNP ID: rs9282860) was identified by TaqMan polymerase chain reaction (PCR) assays in DNA samples available from two other siblings. Further screening was carried out in samples from 654 relapsing-remitting MS patients, 100 primary progressive MS patients, and 661 controls. The STK11-SNP has increased frequency in all female patients versus controls (odds ratio = 1.66, 95% CI = 1.05, 2.64, p = .032). The STK11-SNP was not associated with disease duration or onset; however, it was significantly associated with reduced severity (assessed by MS severity scores), with the lowest scores in patients who also harbored the HLA-DRB1*1501 allele. In vitro studies showed that peripheral blood mononuclear cells from members of the family were more sensitive to the mitochondrial inhibitor metformin than cells from MS patients with the major STK11 allele. The increased association of SNP rs9282860 in women with MS defines this variant as a genetic risk factor. The lower disease severity observed in the context of HLA-DRB1*1501 combined with limited in vitro studies raises the provocative possibility that cells harboring the STK11-SNP could be targeted by drugs which increase metabolic stress.
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Affiliation(s)
- Anne I Boullerne
- Department of Anesthesiology, University of Illinois at Chicago, IL, USA
| | - Demetrios Skias
- Department of Veterans Affairs, Jesse Brown VA Medical Center, Chicago, IL, USA Department of Neurology, University of Illinois at Chicago, IL, USA
| | | | | | - Sergey Kalinin
- Department of Anesthesiology, University of Illinois at Chicago, IL, USA
| | - Paul E Polak
- Department of Anesthesiology, University of Illinois at Chicago, IL, USA
| | - Douglas L Feinstein
- Department of Anesthesiology, University of Illinois at Chicago, IL, USA Department of Veterans Affairs, Jesse Brown VA Medical Center, Chicago, IL, USA
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30
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Huber AK, Duncker PC, Irani DN. Immune responses to non-tumor antigens in the central nervous system. Front Oncol 2014; 4:328. [PMID: 25431758 PMCID: PMC4230036 DOI: 10.3389/fonc.2014.00328] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 10/30/2014] [Indexed: 12/16/2022] Open
Abstract
The central nervous system (CNS), once viewed as an immune-privileged site protected by the blood-brain barrier (BBB), is now known to be a dynamic immunological environment through which immune cells migrate to prevent and respond to events such as localized infection. During these responses, endogenous glial cells, including astrocytes and microglia, become highly reactive and may secrete inflammatory mediators that regulate BBB permeability and recruit additional circulating immune cells. Here, we discuss the various roles played by astrocytes, microglia, and infiltrating immune cells during host immunity to non-tumor antigens in the CNS, focusing first on bacterial and viral infections, and then turning to responses directed against self-antigens in the setting of CNS autoimmunity.
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Affiliation(s)
- Amanda K Huber
- Department of Neurology, University of Michigan Medical School , Ann Arbor, MI , USA
| | - Patrick C Duncker
- Department of Neurology, University of Michigan Medical School , Ann Arbor, MI , USA
| | - David N Irani
- Department of Neurology, University of Michigan Medical School , Ann Arbor, MI , USA
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31
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Goodin DS. The epidemiology of multiple sclerosis: insights to disease pathogenesis. HANDBOOK OF CLINICAL NEUROLOGY 2014; 122:231-66. [PMID: 24507521 DOI: 10.1016/b978-0-444-52001-2.00010-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The purpose of studying the epidemiology of multiple sclerosis (MS) is twofold. First, it is important to understand clearly the natural history of the illness in order to assist patients in making decisions about their future with respect to issues such as family planning, the importance of securing lifelong healthcare, their ability to get and maintain employment, and making appropriate choices of therapy for their particular circumstances. This is not to suggest that, even with the best possible information, the ultimate prognosis for any individual can be predicted with absolute accuracy. It cannot. Nevertheless, accurate information can be very helpful both to reassure patients that many individuals with MS do remarkably well in the long term (perhaps, especially, with current and future therapies) and also to empower individuals with respect to their ability to make their own life choices. Second, and arguably the more important purpose for studying the epidemiology of MS, is to gain insights to the underlying causes of the disease. Indeed, if the principal mechanisms of disease pathogenesis were to be understood clearly, then it might be possible to entertain notions of either a cure for existing disease or the primary prevention of future disease. Much of our current understanding of disease pathogenesis, as discussed in other chapters of this volume, has been derived from basic science investigations of animal models of MS such as experimental autoimmune encephalomyelitis (EAE), and these models have provided considerable insight both to the complexity of the mammalian immune system and to the mechanisms underlying its dysfunction in inflammatory autoimmune conditions. Nevertheless, MS is a disease of humans without any known, naturally occurring, counterpart in any nonhuman species. For this reason, the clues to disease pathogenesis provided by a study of basic epidemiologic facts regarding MS (and by a systematic consideration of their implications) are essential to a comprehensive understanding of the human illness we call MS.
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Affiliation(s)
- Douglas S Goodin
- Department of Neurology, University of California, San Francisco, USA.
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32
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Westerlind H, Ramanujam R, Uvehag D, Kuja-Halkola R, Boman M, Bottai M, Lichtenstein P, Hillert J. Modest familial risks for multiple sclerosis: a registry-based study of the population of Sweden. ACTA ACUST UNITED AC 2014; 137:770-8. [PMID: 24441172 PMCID: PMC3927700 DOI: 10.1093/brain/awt356] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In a study based on 96% of the roughly 28,000 patients with multiple sclerosis (MS) in Sweden, Westerlind et al. report relative and absolute MS risks for relatives of patients. Risks were lower than most of those previously reported, with an MS sibling risk seven times that of randomly selected controls. Data on familial recurrence rates of complex diseases such as multiple sclerosis give important hints to aetiological factors such as the importance of genes and environment. By linking national registries, we sought to avoid common limitations of clinic-based studies such as low numbers, poor representation of the population and selection bias. Through the Swedish Multiple Sclerosis Registry and a nationwide hospital registry, a total of 28 396 patients with multiple sclerosis were identified. We used the national Multi-Generation Registry to identify first and second degree relatives as well as cousins, and the Swedish Twin Registry to identify twins of patients with multiple sclerosis. Crude and age corrected familial risks were estimated for cases and found to be in the same range as previously published figures. Matched population-based controls were used to calculate relative risks, revealing lower estimates of familial multiple sclerosis risks than previously reported, with a sibling recurrence risk (λs = 7.1; 95% confidence interval: 6.42–7.86). Surprisingly, despite a well-established lower prevalence of multiple sclerosis amongst males, the relative risks were equal among maternal and paternal relations. A previously reported increased risk in maternal relations could thus not be replicated. An observed higher transmission rate from fathers to sons compared with mothers to sons suggested a higher transmission to offspring from the less prevalent sex; therefore, presence of the so-called ‘Carter effect’ could not be excluded. We estimated the heritability of multiple sclerosis using 74 757 twin pairs with known zygosity, of which 315 were affected with multiple sclerosis, and added information from 2.5 million sibling pairs to increase power. The heritability was estimated to be 0.64 (0.36–0.76), whereas the shared environmental component was estimated to be 0.01 (0.00–0.18). In summary, whereas multiple sclerosis is to a great extent an inherited trait, the familial relative risks may be lower than usually reported.
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Affiliation(s)
- Helga Westerlind
- 1 Department of Clinical Neuroscience, Karolinska Institutet, Sweden
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Handunnetthi L, Handel AE, Ramagopalan SV. Contribution of genetic, epigenetic and transcriptomic differences to twin discordance in multiple sclerosis. Expert Rev Neurother 2014; 10:1379-81. [DOI: 10.1586/ern.10.116] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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34
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Abstract
Familial aggregation and the studies of twins indicate that heredity contributes to multiple sclerosis (MS) risk. Immunologic studies of leukocyte antigens subsequently followed by gene-mapping techniques identified the primary MS susceptibility locus to be within the major histocompatibility complex (MHC). The primary risk allele is HLA-DRB1*15, although other alleles of this gene also influence MS susceptibility. Other genes within the MHC also contribute to MS susceptibility. Genome-wide association studies have identified over 50 additional common variants of genes across the genome. Estimates suggest that there may be as many as 200 genes involved in MS susceptibility. In addition to these common polymorphisms, studies have identified several rare risk alleles in some families. Interestingly, the majority of the genes identified have known immunologic functions and many contribute to the risk of inheriting other autoimmune diseases. Genetic variants in the vitamin D metabolic pathway have also been identified. That vitamin D contributes to MS susceptibility as both an environmental as well as genetic risk factor underscores the importance of this metabolic pathway in disease pathogenesis. Current efforts are focused on understanding how the myriad of genetic risk alleles interact within networks to influence MS risk at family level as well as within populations.
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Affiliation(s)
- Bruce A C Cree
- Department of Neurology, University of California, San Francisco, USA.
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35
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Shin JG, Kim HJ, Park BL, Bae JS, Kim LH, Cheong HS, Shin HD. Putative association of GPC5 polymorphism with the risk of inflammatory demyelinating diseases. J Neurol Sci 2013; 335:82-8. [DOI: 10.1016/j.jns.2013.08.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 08/19/2013] [Accepted: 08/21/2013] [Indexed: 11/27/2022]
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36
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Multiple sclerosis genetics is dead. Mult Scler Relat Disord 2013; 2:156-61. [DOI: 10.1016/j.msard.2012.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 11/24/2022]
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Cortes A, Field J, Glazov EA, Hadler J, Stankovich J, Brown MA. Resequencing and fine-mapping of the chromosome 12q13-14 locus associated with multiple sclerosis refines the number of implicated genes. Hum Mol Genet 2013; 22:2283-92. [PMID: 23406874 DOI: 10.1093/hmg/ddt062] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Multiple sclerosis (MS) is a common chronic inflammatory disease of the central nervous system. Susceptibility to the disease is affected by both environmental and genetic factors. Genetic factors include haplotypes in the histocompatibility complex (MHC) and over 50 non-MHC loci reported by genome-wide association studies. Amongst these, we previously reported polymorphisms in chromosome 12q13-14 with a protective effect in individuals of European descent. This locus spans 288 kb and contains 17 genes, including several candidate genes which have potentially significant pathogenic and therapeutic implications. In this study, we aimed to fine-map this locus. We have implemented a two-phase study: a variant discovery phase where we have used next-generation sequencing and two target-enrichment strategies [long-range polymerase chain reaction (PCR) and Nimblegen's solution phase hybridization capture] in pools of 25 samples; and a genotyping phase where we genotyped 712 variants in 3577 healthy controls and 3269 MS patients. This study confirmed the association (rs2069502, P = 9.9 × 10(-11), OR = 0.787) and narrowed down the locus of association to an 86.5 kb region. Although the study was unable to pinpoint the key-associated variant, we have identified a 42 (genotyped and imputed) single-nucleotide polymorphism haplotype block likely to harbour the causal variant. No evidence of association at previously reported low-frequency variants in CYP27B1 was observed. As part of the study we compared variant discovery performance using two target-enrichment strategies. We concluded that our pools enriched with Nimblegen's solution phase hybridization capture had better sensitivity to detect true variants than the pools enriched with long-range PCR, whilst specificity was better in the long-range PCR-enriched pools compared with solution phase hybridization capture enriched pools; this result has important implications for the design of future fine-mapping studies.
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Affiliation(s)
- Adrian Cortes
- University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Qld. 4102, Australia
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38
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Goodin DS. The genetic and environmental bases of complex human-disease: extending the utility of twin-studies. PLoS One 2012; 7:e47875. [PMID: 23272039 PMCID: PMC3525648 DOI: 10.1371/journal.pone.0047875] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 09/24/2012] [Indexed: 12/03/2022] Open
Abstract
Making only the assumption that twins are representative of the population from which they are drawn, we here develop a simple mathematical model (using widely available epidemiological information) that sheds considerable light on the pathogenesis of complex human diseases. Specifically, for the case of multiple sclerosis (MS), we demonstrate that the vast majority of patients (≥94%), possibly all, require genetic susceptibility in order to get MS. Nevertheless, only a tiny fraction of the population (≤2.2%) is actually susceptible to getting this disease; a finding which is highly consistent in all of the studied populations across both North America and Europe. Men are more likely to be susceptible than women although susceptible women are more than twice as likely to actually develop MS compared to susceptible men (i.e., they have a greater disease penetrance). This is because women are more responsive to the environmental factors involved in MS pathogenesis than men. These differences account for the current gender-ratio (3∶1, favoring women) and also for the increasing incidence of MS in women around the world. By contrast, the most important genetic marker for MS susceptibility (DRB1*1501) influences the likelihood of susceptibility but not the penetrance of the disease. Nevertheless, even for this major susceptibility allele, only a very small fraction of DRB1*1501carriers (<5%) are susceptible to getting MS and for only a minority of MS patients (∼41%) does this allele contribute to their susceptibility. Moreover, each copy of this allele seems to make an independent contribution to susceptibility. Finally, at least three environmental events are necessary for MS pathogenesis and, during the course of their lives, the large majority of the population (≥69%) experiences an environmental exposure, which is sufficient to produce MS in, at least, some susceptible genotypes. Also, susceptible men (compared to susceptible women) have a lower threshold, a greater hazard-rate, or both in response to the environmental factors involved in MS pathogenesis.
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Affiliation(s)
- Douglas S Goodin
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America.
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39
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Waubant E, Mowry EM, Krupp L, Chitnis T, Yeh EA, Kuntz N, Ness J, Belman A, Milazzo M, Gorman M, Weinstock-Guttman B, Rodriguez M, James JA. Antibody response to common viruses and human leukocyte antigen-DRB1 in pediatric multiple sclerosis. Mult Scler 2012; 19:891-5. [PMID: 23232601 DOI: 10.1177/1352458512469693] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND As remote infections with common herpes viruses are associated with modulation of the risk of multiple sclerosis (MS), we hypothesized that antibody concentrations against these viruses may further modify risk. As many common viruses are first encountered during childhood, pediatric MS offer a unique opportunity to investigate more closely their influence on susceptibility. Our aim was to determine if MS patients who were positive for these viruses had higher levels of antibodies to these viruses. We also assessed whether human leukocyte antigen (HLA)-DRB1*1501 genotype influenced viral antibody levels. METHODS Antibody response levels toward Epstein Barr virus (EBV), cytomegalovirus (CMV), and herpes simplex virus (HSV)-1, and HLA-DRB1*1501 status were determined in pediatric MS patients (n=189) and controls (n=38). Multivariate analyses were used, adjusted for age, gender, race, ethnicity and use of disease-modifying therapies. RESULTS The antibody concentrations against EBV (Epstein-Barr nuclear antigen 1 (EBNA-1), viral capsid antigen (VCA) and early antigen (EA)), CMV and HSV-1 were similar between pediatric MS patients and controls positive for seroconversion against the virus of interest. EBNA-1 humoral responses were higher in HLA-DRB1 positive individuals (p=0.005) whereas other viral humoral responses were similar in HLA-DRB1 positive and negative individuals. CONCLUSION Among those positive for EBNA-1, MS patients did not have higher levels of antibody response to EBNA-1: however, titers for EBNA-1 were higher in those who were HLA-DRB1 positive. This suggests that genotype might influence the humoral response to EBV. Whether other genotypes influence antibody response to other viruses remains to be determined.
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Affiliation(s)
- Emmanuelle Waubant
- Regional Pediatric Multiple Sclerosis Center, University of California San Francisco, San Francisco, CA 94158, USA.
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40
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The USC Adult Twin Cohorts: International Twin Study and California Twin Program. Twin Res Hum Genet 2012; 16:366-70. [PMID: 23218448 DOI: 10.1017/thg.2012.134] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The study of twin subjects permits the documentation of crude heritability and may promote the identification of specific causal alleles. We believe that at the current time, the chief research advantage of twins as subjects, especially monozygotic twins, is that the commonality of their genetic and cultural identity simplifies the interpretation of biological associations. In order to study genetic and environmental determinants of cancer and chronic diseases, we developed two twin registries, maintained at the University of Southern California: The International Twin Study (ITS) and the California Twin Program (CTP). The ITS is a volunteer registry of twins with cancer and chronic disease consisting of 17,245 twin pairs affected by cancer and chronic disease, respectively, ascertained by advertising in periodicals from 1980-1991. The CTP is a population-based registry of California-born twin pairs ascertained by linking the California birth records to the State Department of Motor Vehicles. Over 51,000 individual California twins representing 36,965 pairs completed and returned 16-page questionnaires. Cancer diagnoses in the California twins are updated by regular linkage to the California Cancer Registry. Over 5,000 cancer patients are represented in the CTP. Twins from both registries have participated extensively in studies of breast cancer, melanoma, lymphoma, multiple sclerosis, systemic lupus erythematosus, diabetes mellitus type 1, mammographic density, smoking, and other traits and conditions.
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41
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Vukusic S. [Prevention of multiple sclerosis: a realistic goal?]. Rev Neurol (Paris) 2012; 168:836-45. [PMID: 22989784 DOI: 10.1016/j.neurol.2012.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Multiple sclerosis (MS) is the most frequent source of chronic neurological disability in Western countries, and its incidence and prevalence are increasing. However, it is possible to determine its prodromal phase and the radiological, biological and immunological endophenotypes that are present before the clinical onset of the disease, despite remaining unseen with the naked eye. In this context, greater knowledge of the aetiological factors, both genetic and environmental, may lead the way towards primary prevention strategies for MS in the near future.
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Affiliation(s)
- S Vukusic
- Service de neurologie A et fondation Eugène Devic EDMUS pour la sclérose en plaques, hôpital neurologique Pierre-Wertheimer, hospices civils de Lyon, 59 boulevard Pinel, Lyon-Bron cedex, France.
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42
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Environmental risk factors for multiple sclerosis: a review with a focus on molecular mechanisms. Int J Mol Sci 2012; 13:11718-11752. [PMID: 23109880 PMCID: PMC3472772 DOI: 10.3390/ijms130911718] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 08/31/2012] [Accepted: 09/06/2012] [Indexed: 12/15/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic disabling disease of the central nervous system commonly affecting young adults. Pathologically, there are patches of inflammation (plaques) with demyelination of axons and oligodendrocyte loss. There is a global latitude gradient in MS prevalence, and incidence of MS is increasing (particularly in females). These changes suggest a major role for environmental factors in causation of disease. We have reviewed the evidence and potential mechanisms of action for three exposures: vitamin D, Epstein Barr virus and cigarette smoking. Recent advances supporting gene-environment interactions are reviewed. Further research is needed to establish mechanisms of causality in humans and to explore preventative strategies.
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43
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Greer JM, McCombe PA. The role of epigenetic mechanisms and processes in autoimmune disorders. Biologics 2012; 6:307-27. [PMID: 23055689 PMCID: PMC3459549 DOI: 10.2147/btt.s24067] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Indexed: 12/18/2022]
Abstract
The lack of complete concordance of autoimmune disease in identical twins suggests that nongenetic factors play a major role in determining disease susceptibility. In this review, we consider how epigenetic mechanisms could affect the immune system and effector mechanisms in autoimmunity and/or the target organ of autoimmunity and thus affect the development of autoimmune diseases. We also consider the types of stimuli that lead to epigenetic modifications and how these relate to the epidemiology of autoimmune diseases and the biological pathways operative in different autoimmune diseases. Increasing our knowledge of these epigenetic mechanisms and processes will increase the prospects for controlling or preventing autoimmune diseases in the future through the use of drugs that target the epigenetic pathways.
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Affiliation(s)
- Judith M Greer
- The University of Queensland, UQ Centre for Clinical Research, Brisbane, Queensland, Australia
| | - Pamela A McCombe
- The University of Queensland, UQ Centre for Clinical Research, Brisbane, Queensland, Australia
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44
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Handel AE, Ramagopalan SV. Vitamin D and multiple sclerosis: an interaction between genes and environment. Mult Scler 2012; 18:2-4. [PMID: 22247498 DOI: 10.1177/1352458511418353] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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45
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Handel AE, Williamson AJ, Ramagopalan SV. Concealed effects of gene–environment interactions in genome-wide association. Mult Scler Relat Disord 2012; 1:39-42. [DOI: 10.1016/j.msard.2011.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 08/05/2011] [Accepted: 08/22/2011] [Indexed: 10/17/2022]
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46
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Bogdanos DP, Smyk DS, Rigopoulou EI, Mytilinaiou MG, Heneghan MA, Selmi C, Gershwin ME. Twin studies in autoimmune disease: genetics, gender and environment. J Autoimmun 2011; 38:J156-69. [PMID: 22177232 DOI: 10.1016/j.jaut.2011.11.003] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 11/12/2011] [Indexed: 02/08/2023]
Abstract
Twin studies are powerful tools to discriminate whether a complex disease is due to genetic or environmental factors. High concordance rates among monozygotic (MZ) twins support genetic factors being predominantly involved, whilst low rates are suggestive of environmental factors. Twin studies have often been utilised in the study of systemic and organ specific autoimmune diseases. As an example, type I diabetes mellitus has been investigated to establish that that disease is largely affected by genetic factors, compared to rheumatoid arthritis or scleroderma, which have a weaker genetic association. However, large twin studies are scarce or virtually non-existent in other autoimmune diseases which have been limited to few sets of twins and individual case reports. In addition to the study of the genetic and environmental contributions to disease, it is likely that twin studies will also provide data in regards to the clinical course of disease, as well as risk for development in related individuals. More importantly, genome-wide association studies have thus far reported genomic variants that only account for a minority of autoimmunity cases, and cannot explain disease discordance in MZ twins. Future research is therefore encouraged not only in the analysis of twins with autoimmune disease, but also in regards to epigenetic factors or rare variants that may be discovered with next-generation sequencing. This review will examine the literature surrounding twin studies in autoimmune disease including discussions of genetics and gender.
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Affiliation(s)
- Dimitrios P Bogdanos
- Institute of Liver Studies, Liver Immunopathology, King's College London School of Medicine at King's College Hospital, London, UK.
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47
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Waubant E, Mowry EM, Krupp L, Chitnis T, Yeh EA, Kuntz N, Ness J, Chabas D, Strober J, McDonald J, Belman A, Milazzo M, Gorman M, Weinstock-Guttman B, Rodriguez M, Oksenberg JR, James JA. Common viruses associated with lower pediatric multiple sclerosis risk. Neurology 2011; 76:1989-95. [PMID: 21646624 DOI: 10.1212/wnl.0b013e31821e552a] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Because common viruses are encountered during childhood, pediatric multiple sclerosis (MS) offers a unique opportunity to investigate the influence of these viruses on disease susceptibility and the interactions between seroprevalence and select HLA genotypes. We studied seroprevalence for Epstein-Barr virus (EBV), cytomegalovirus (CMV), and herpes simplex virus (HSV) type 1 and HLA-DRB1*1501/1503 status as predictors of pediatric MS. METHODS This was a retrospective analysis of prospectively collected demographic, clinical, and biologic data in subjects up to 18 years of age with early MS, control subjects seen at the same regional referral pediatric MS clinics, and additional healthy pediatric control subjects. RESULTS Patients with early pediatric MS (n=189) and pediatric control subjects (n=66) were tested. Epstein-Barr nuclear antigen-1 seropositivity was associated with an increased odds of MS (odds ratio [OR] 3.78, 95% confidence interval [CI] 1.52-9.38, p=0.004) in analyses adjusted for age, sex, race, ethnicity, and HLA-DRB1*1501/1503 status. In multivariate analyses including EBV status, a remote infection with CMV (OR 0.27, 95% CI 0.11-0.67, p=0.004) was associated with a lower risk of developing MS. Although a remote infection with HSV-1 was not associated with an increased odds of MS, a strong interaction was found between HSV-1 status and HLA-DRB1 in predicting MS (p<0.001). HSV-1 was associated with an increased risk of MS in those without a DRB1*15 allele (OR 4.11, 95% CI 1.17-14.37, p=0.03), whereas the effect was reversed in those who were DRB1*15-positive (OR 0.07, 95% CI 0.02-0.32, p=0.001). CONCLUSIONS These findings suggest that some infections with common viruses may in fact lower MS susceptibility. If this is confirmed, the pathways for risk modification remain to be elucidated.
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Affiliation(s)
- E Waubant
- UCSF Regional Pediatric Multiple Sclerosis Center, 350 Parnassus Ave., Suite 908, San Francisco, CA 94117, USA.
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McDowell TY, Amr S, Culpepper WJ, Langenberg P, Royal W, Bever C, Bradham DD. Sun exposure, vitamin D intake and progression to disability among veterans with progressive multiple sclerosis. Neuroepidemiology 2011; 37:52-7. [PMID: 21822026 DOI: 10.1159/000329258] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 05/11/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Early life events have been suggested to influence multiple sclerosis (MS) susceptibility, and to potentially modulate its clinical course. We assessed vitamin D-related exposures from childhood to disease onset and their associations with MS progression. METHODS Among veterans in the Multiple Sclerosis Surveillance Registry, 219 reported having the progressive form and met the inclusion criteria. Participants reported their past sun exposure, vitamin D-related intake and age at disability milestones using the Patient-Determined Disease Steps (PDDS). The Cox proportional hazards model was used to examine the association between vitamin D-related exposures and time (years) to disability. RESULTS Low average sun exposure in the fall/winter before disease onset was associated with an increased risk of progressing to a PDDS score of 8 (hazard ratio, HR: 2.13, 95% confidence interval, CI: 1.20-3.78), whereas use of cod liver oil during childhood and adolescence was associated with a reduced risk (HR: 0.44, 95% CI: 0.20-0.96). CONCLUSIONS These results suggest that exposure to vitamin D before MS onset might slow disease-related neurodegeneration and thus delay progression to disability among patients with the progressive subtype.
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Affiliation(s)
- Tzu-Yun McDowell
- MS Center of Excellence-East, Baltimore VAMC, University of Maryland, Baltimore School of Medicine, Baltimore, MD, USA.
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Sawcer S. The genetic aspects of multiple sclerosis. Ann Indian Acad Neurol 2011; 12:206-14. [PMID: 20182566 PMCID: PMC2824946 DOI: 10.4103/0972-2327.58272] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Accepted: 07/06/2009] [Indexed: 12/18/2022] Open
Abstract
The epidemiology of multiple sclerosis has been extensively investigated and two features have consistently emerged: marked geographical variation in prevalence and substantial familial clustering. At first sight, geographic variation would seem to imply an environmental cause for the disease, while familial clustering would seem to suggest that genetic factors have the predominant etiological effect. However, given that geographic variation in prevalence could result from variation in the frequency of genetic risk alleles and that familial clustering might result from shared environmental exposure rather than shared genetic risk alleles, it is clear that these crude inferences are unreliable. Epidemiologists have been resourceful in their attempts to resolve this apparent conflict between “nurture and nature” and have employed a whole variety of sophisticated methods to try and untangle the etiology of multiple sclerosis. The body of evidence that has emerged from these efforts has formed the foundation for decades of research seeking to identify relevant genes and this is the obvious place to start any consideration of the genetics of multiple sclerosis.
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Affiliation(s)
- Stephen Sawcer
- University of Cambridge, Department of Clinical Neurosciences, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 2QQ, UK
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Al Jumah M, Kojan S, Al Khathaami A, Al Abdulkaream I, Al Blawi M, Jawhary A. Familial multiple sclerosis: does consanguinity have a role? Mult Scler 2010; 17:487-9. [PMID: 21177327 DOI: 10.1177/1352458510390406] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Parental consanguinity (PC) may be a risk factor for familial multiple sclerosis (FMS) throughout inbred communities. The objective of this report was to estimate prevalence of FMS and rate of PC among FMS versus non-FMS patients. All Saudi MS patients were identified from our registry. The history of PC was analyzed as a case-control study. In total 141 MS patients were identified. Of these, 30 (21%) reported having at least one affected relative, 37.6% reported PC and 16% presented first-degree PC. In addition, FMS patients were more likely than non-FMS patients to report PC. In conclusion, FMS is prevalent among Saudi MS patients. MS patients with a history of PC were more likely to have FMS, suggesting a potential role of consanguinity.
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Affiliation(s)
- M Al Jumah
- King Abdullah International Medical Research Center, KSAU-HS, Riyadh, Saudi Arabia.
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