Evaluation of the established non-MHC multiple sclerosis loci in an Indian population

Meta-analysis of the Selected Genetic Variants in Immune-Related Genes and Multiple Sclerosis Risk

Previous studies have suggested that certain variants in immune-related genes may participate in the pathogenesis of multiple sclerosis (MS), including rs17824933 in the CD6 gene, rs1883832 in the CD40 gene, rs2300747 in the CD58 gene, rs763361 in the CD226 gene, rs16944 in the IL-1β gene, rs2243250 in the IL-4 gene, and rs12722489 and rs2104286 in the IL-2Rα gene. However, the results remained inconclusive and conflicting. In view of this, a comprehensive meta-analysis including all eligible studies was conducted to investigate the association between these 8 selected genetic variants and MS risk. Up to June 2023, 64 related studies were finally included in this meta-analysis. The odds ratios (ORs) and corresponding 95% confidence intervals (CIs) calculated by the random-effects model were used to evaluate the strength of association. Publication bias test, sensitivity analyses, and trial sequential analysis (TSA) were conducted to examine the reliability of statistical results. Our results indicated that rs17824933 in the CD6 gene, rs1883832 in the CD40 gene, rs2300747 in the CD58 gene, rs763361 in the CD226 gene, and rs12722489 and rs2104286 in the IL-2Rα gene may serve as the susceptible factors for MS pathogenesis, while rs16944 in the IL-1β gene and rs2243250 in the IL-4 gene may not be associated with MS risk. However, the present findings need to be confirmed and reinforced in future studies.

Association of CD58 rs12044852 and rs2300747 polymorphisms with the risk of multiple sclerosis: A systematic review and meta-analysis

OBJECTIVE

Multiple sclerosis is a serious neurodegenerative disorder that causes disability in young adults. Genetic predisposition of multiple sclerosis is well documented and several single nucleotide polymorphisms (SNPs) of the CD58 were found to be associated with this disease. This systematic review and meta-analysis were done with the aim of finding the association between CD58 gene SNPs (rs12044852 and rs2300747) and the risk of multiple sclerosis (MS).

METHOD

A comprehensive search was done in PubMed, Google Scholar, Embase, and MSGene.org to find the relevant data. Our search yielded 13 relevant publications which were included for meta-analysis consisting of 5194 cases and 5766 controls. All the statistical analysis was conducted using meta and metafor packages in R studio. The odds ratio (OR) along with 95 % confidence intervals and p values were determined using the fixed effects and random effects model. The I2 test was done to measure heterogeneity. Subgroup analysis was performed along with analysis for publication bias.

RESULTS

We found significant association for both rs12044852 (allelic, dominant, over-dominant, heterozygous, and homozygous models) and rs2300747 (allelic, dominant, over-dominant, heterozygous models) with multiple sclerosis. Both the SNPs provided a protective effect for multiple sclerosis. Subgroup analysis indicated that rs12044852 polymorphism provided a protective effect in both Asians and Caucasians. However, for rs2300747, the Asian population showed no statistically significant association with the risk of MS.

CONCLUSION

Polymorphism of rs12044852 and rs2300747 of the CD58 gene provided a protective effect for multiple sclerosis. The protective effect is more prominent in Caucasian populations compared to Asians.

SOCS-JAK-STAT inhibitors and SOCS mimetics as treatment options for autoimmune uveitis, psoriasis, lupus, and autoimmune encephalitis

Autoimmune diseases arise from atypical immune responses that attack self-tissue epitopes, and their development is intricately connected to the disruption of the JAK-STAT signaling pathway, where SOCS proteins play crucial roles. Conditions such as autoimmune uveitis, psoriasis, lupus, and autoimmune encephalitis exhibit immune system dysfunctions associated with JAK-STAT signaling dysregulation. Emerging therapeutic strategies utilize JAK-STAT inhibitors and SOCS mimetics to modulate immune responses and alleviate autoimmune manifestations. Although more research and clinical studies are required to assess their effectiveness, safety profiles, and potential for personalized therapeutic approaches in autoimmune conditions, JAK-STAT inhibitors and SOCS mimetics show promise as potential treatment options. This review explores the action, effectiveness, safety profiles, and future prospects of JAK inhibitors and SOCS mimetics as therapeutic agents for psoriasis, autoimmune uveitis, systemic lupus erythematosus, and autoimmune encephalitis. The findings underscore the importance of investigating these targeted therapies to advance treatment options for individuals suffering from autoimmune diseases.

ADAMS project: a genetic Association study in individuals from Diverse Ancestral backgrounds with Multiple Sclerosis based in the UK

PURPOSE

Genetic studies of multiple sclerosis (MS) susceptibility and severity have focused on populations of European ancestry. Studying MS genetics in other ancestral groups is necessary to determine the generalisability of these findings. The genetic Association study in individuals from Diverse Ancestral backgrounds with Multiple Sclerosis (ADAMS) project aims to gather genetic and phenotypic data on a large cohort of ancestrally-diverse individuals with MS living in the UK.

PARTICIPANTS

Adults with self-reported MS from diverse ancestral backgrounds. Recruitment is via clinical sites, online (https://app.mantal.co.uk/adams) or the UK MS Register. We are collecting demographic and phenotypic data using a baseline questionnaire and subsequent healthcare record linkage. We are collecting DNA from participants using saliva kits (Oragene-600) and genotyping using the Illumina Global Screening Array V.3.

FINDINGS TO DATE

As of 3 January 2023, we have recruited 682 participants (n=446 online, n=55 via sites, n=181 via the UK MS Register). Of this initial cohort, 71.2% of participants are female, with a median age of 44.9 years at recruitment. Over 60% of the cohort are non-white British, with 23.5% identifying as Asian or Asian British, 16.2% as Black, African, Caribbean or Black British and 20.9% identifying as having mixed or other backgrounds. The median age at first symptom is 28 years, and median age at diagnosis is 32 years. 76.8% have relapsing-remitting MS, and 13.5% have secondary progressive MS.

FUTURE PLANS

Recruitment will continue over the next 10 years. Genotyping and genetic data quality control are ongoing. Within the next 3 years, we aim to perform initial genetic analyses of susceptibility and severity with a view to replicating the findings from European-ancestry studies. In the long term, genetic data will be combined with other datasets to further cross-ancestry genetic discoveries.

CLEC16A-An Emerging Master Regulator of Autoimmunity and Neurodegeneration

CLEC16A is emerging as an important genetic risk factor for several autoimmune disorders and for Parkinson disease (PD), opening new avenues for translational research and therapeutic development. While the exact role of CLEC16A in health and disease is still being elucidated, the gene plays a critical role in the regulation of autophagy, mitophagy, endocytosis, intracellular trafficking, immune function, and in biological processes such as insulin secretion and others that are important to cellular homeostasis. As shown in both human and animal modeling studies, CLEC16A hypofunction predisposes to both autoinflammatory phenotype and neurodegeneration. While the two are clearly related, further functional studies are needed to fully understand the mechanisms involved for optimized therapeutic interventions. Based on recent data, mitophagy-inducing drugs may be warranted, and such therapy should be tested in clinical trials as these drugs would tackle the underlying pathogenic mechanism (s) and could treat or prevent symptoms of autoimmunity and neurodegeneration in individuals with CLEC16A risk variants. Accordingly, interventions directed at reversing the dysregulated mitophagy and the consequences of loss of function of CLEC16A without activating other detrimental cellular pathways could present an effective therapy. This review presents the emerging role of CLEC16A in health and disease and provides an update on the disease processes that are attributed to variants located in the CLEC16A gene, which are responsible for autoimmune disorders and neurodegeneration with emphasis on how this information is being translated into practical and effective applications in the clinic.

Polygenic risk score prediction of multiple sclerosis in individuals of South Asian ancestry

Polygenic risk scores aggregate an individual's burden of risk alleles to estimate the overall genetic risk for a specific trait or disease. Polygenic risk scores derived from genome-wide association studies of European populations perform poorly for other ancestral groups. Given the potential for future clinical utility, underperformance of polygenic risk scores in South Asian populations has the potential to reinforce health inequalities. To determine whether European-derived polygenic risk scores underperform at multiple sclerosis prediction in a South Asian-ancestry population compared with a European-ancestry cohort, we used data from two longitudinal genetic cohort studies: Genes & Health (2015-present), a study of ∼50 000 British-Bangladeshi and British-Pakistani individuals, and UK Biobank (2006-present), which is comprised of ∼500 000 predominantly White British individuals. We compared individuals with and without multiple sclerosis in both studies (Genes & Health: N Cases = 42, N Control = 40 490; UK Biobank: N Cases = 2091, N Control = 374 866). Polygenic risk scores were calculated using clumping and thresholding with risk allele effect sizes obtained from the largest multiple sclerosis genome-wide association study to date. Scores were calculated with and without the major histocompatibility complex region, the most influential locus in determining multiple sclerosis risk. Polygenic risk score prediction was evaluated using Nagelkerke's pseudo-R 2 metric adjusted for case ascertainment, age, sex and the first four genetic principal components. We found that, as expected, European-derived polygenic risk scores perform poorly in the Genes & Health cohort, explaining 1.1% (including the major histocompatibility complex) and 1.5% (excluding the major histocompatibility complex) of disease risk. In contrast, multiple sclerosis polygenic risk scores explained 4.8% (including the major histocompatibility complex) and 2.8% (excluding the major histocompatibility complex) of disease risk in European-ancestry UK Biobank participants. These findings suggest that polygenic risk score prediction of multiple sclerosis based on European genome-wide association study results is less accurate in a South Asian population. Genetic studies of ancestrally diverse populations are required to ensure that polygenic risk scores can be useful across ancestries.

Towards a global view of multiple sclerosis genetics

Multiple sclerosis (MS) is a neuroimmunological disorder of the CNS with a strong heritable component. The genetic architecture of MS susceptibility is well understood in populations of European ancestry. However, the extent to which this architecture explains MS susceptibility in populations of non-European ancestry remains unclear. In this Perspective article, we outline the scientific arguments for studying MS genetics in ancestrally diverse populations. We argue that this approach is likely to yield insights that could benefit individuals with MS from all ancestral groups. We explore the logistical and theoretical challenges that have held back this field to date and conclude that, despite these challenges, inclusion of participants of non-European ancestry in MS genetics studies will ultimately be of value to all patients with MS worldwide.

Evaluating the Role of HLA DRB1 Alleles and Oligoclonal Bands in Influencing Clinical Course of Multiple Sclerosis - A Study from the Mangalore Demyelinating Disease Registry

Background:

The possible interaction between genetic and immunological factors in influencing clinical course of multiple sclerosis (MS) has not been studied previously in Indian population.

Aim:

In this study we evaluated the association of HLA alleles and OCB in affecting clinical course and disability of MS.

Methods:

Clinical and demographic features of 145 MS patients who had CSF oligoclonal bands (OCB) tested by isoelectric focussing technique were analyzed, disability status estimated, and HLA DRB1 alleles were genotyped.

Results:

OCBs were positive in 53.8% (78/145) of all MS cases. Patients with CSF OCB had more frequent relapses and an association with HLA DRB1*15. Early disease onset and a high annualized relapse rate was associated with HLA DRB1*03 allele. A relapsing remitting course for MS was seen with HLA DRB1*03 & 15 while a progressive disease was associated with DRB1*01. Presence of both OCB and HLA DRB1*13 was significantly associated with disability in this cohort.

Conclusion:

The results of our study suggest that an interaction between immunological and genetic factors may influence disease onset, course, and disability in MS.

Soluble IL-7Rα/sCD127 in Health, Disease, and Its Potential Role as a Therapeutic Agent

Soluble cytokine receptors can influence immune responses by modulating the biological functions of their respective ligands. These effects can be either agonistic or antagonistic and a number of soluble cytokine receptors have been shown to play critical roles in both maintenance of health and disease pathogenesis. Soluble IL-7Ra (sCD127) is one such example. With its impact on the IL-7/CD127 pathway, which is fundamental for the development and homeostasis of T cells, the role of sCD127 in health and disease has been extensively studied in recent years. Within this review, the role of sCD127 in maintaining host immune function is presented. Next, by addressing genetic factors affecting sCD127 expression and the associated levels of sCD127 production, the roles of sCD127 in autoimmune disease, infections and cancer are described. Finally, advances in the field of soluble cytokine therapy and the potential for sCD127 as a biomarker and therapeutic agent are discussed.

High-resolution melting curve analysis of polymorphisms within CD58, CD226, HLA-G genes and association with multiple sclerosis susceptibility in a subset of Iranian population: a case-control study

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system with unknown etiology, which typically is manifested in early to middle adulthood. Recently, genome-wide association studies have identified susceptibility of immune-related genes to be involved in MS predisposition. The goal of the current study was to investigate the association of single nucleotide polymorphisms (SNP) with the immunologically related genes responsible for the disease, composed of CD58 (rs2300747 A>G), CD226 (rs763361 C>T), and HLA-G (rs1611715 A>C), with MS susceptibility. In this case-control study, a total of 200 patients suffering from relapsing-remitting multiple sclerosis and 200 healthy individuals were recruited. DNA was extracted from blood and then all subjects were genotyped for the polymorphism within mentioned genes by high-resolution melting (HRM) real-time PCR method. Statistical analyses were performed using SPSS software (version 20; SPSS, Chicago, IL, USA). Our finding showed that there are significant differences in genotype and allele frequencies between two groups regarding rs763361 (P = 0.035, OR 0.64, CI 95% for C allele) and rs1611715 (P = 0.038, OR 1.57, CI 95% for AA genotype) polymorphisms within CD226 and HLA-G genes, respectively. Concerning rs2300747 polymorphism on CD58 gene, no significant differences were found between cases and controls. In general, results from the current study indicate that CD226 and HLA-G, but not CD58 genetic polymorphisms are associated with increased risk of MS in Isfahan population similar to European populations. However, to elucidate how these SNPs contribute to MS pathogenesis, functional studies are needed.

Association of CD58 polymorphism and multiple sclerosis in Malaysia: a pilot study

Background

Multiple sclerosis is an immune mediated disease targeting the central nervous system. Association of non-human leukocyte antigen gene, CD58, with multiple sclerosis has been reported in several populations but is unclear among Southeast Asians. This pilot study was conducted to explore the association between CD58 polymorphism and multiple sclerosis among the Malay population in Malaysia.

Methods

Blood samples were collected from 27 multiple sclerosis patients, and compared with 58 age- and gender matched healthy individuals. All patients were tested negative for anti-aquaporin 4. DNA was extracted from the blood and genotyped for 3 single nucleotide polymorphisms rs12044852, rs2300747 and rs1335532 of gene CD58 by real-time PCR.

Results

The majority of multiple sclerosis patients were female (85.2%). The general mean age of onset was 30.5 years. Genotyping results showed that frequencies of the alleles were between 40 and 50% for MS patients and healthy individuals. Association (allelic model) between multiple sclerosis and CD58 gene polymorphism alleles rs12044852 (p = 0.410), rs2300747 (p = 0.881) and rs1335532 (p = 0.407) were indistinct.

Conclusions

The impact of the CD58 gene polymorphism was not prominent in this pilot study, implying that genetic composition contributing to multiple sclerosis may be different between different populations, thus results in a heterogeneity of disease manifestation and distribution.

First report of THOC6 related intellectual disability (Beaulieu Boycott Innes syndrome) in two siblings from India

THOC6 is a newly described causal gene for an autosomal recessive intellectual disability (ID) - Beaulieu Boycott Innes syndrome (BBIS) (OMIM # 613680). It is characterized by ID with dysmorphic facies, genitourinary, cardiac anomalies, and dentition problems. Here, we report the first two siblings of BBIS from the Indian subcontinent with previously unreported skeletal anomalies such as Sprengel shoulder, calcaneo valgus deformity, radioulnar dysostosis, and overlapping toes. Whole exome sequencing (WES) identified previously reported three missense variants (p.Trp100Arg, p.Val234Leu, p.Gly275Asp) in THOC6. THOC6 is a subunit of TRanscription and EXport (TREX) complex involved in mRNA transcription, processing, and nuclear export of spliced mRNAs and has a potential role in neurodevelopment. Till date, only 12 patients with BBIS have been reported. This report reviews the phenotypic and genetic data of known BBIS cases in addition to the new phenotypic features, thereby expanding the phenotype of this rare syndrome.

Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disorder. Although all MS patients initially show a relapsing-remitting course, 20-50% subsequently enter a chronic progressive course at 10-20 years after onset that greatly influences their activities of daily living. There are 2.5 million MS patients worldwide with large regional and racial differences. In particular, there are many MS patients among Caucasians living in Europe, while the disease is relatively rare in Asians and Africans.Although MS is regarded as an autoimmune disease, many factors such as genetic background, environmental factors, and sex are involved in its pathogenesis. While the immunological mechanisms remain to be fully elucidated, invasion of autoreactive T cells into the central nervous system (CNS) tissue is considered the first step of the disease. These T cells react with myelin antigens and initiate demyelination of the CNS by activating cytotoxic T cells, macrophages, and B cells through the release of inflammatory cytokines. As a treatment option, disease-modifying therapies have recently been developed to prevent the recurrence of MS in addition to conventional treatment with corticosteroids for acute relapse. However, there are still few effective treatments for the chronic progressive phase, and it is thus imperative to decipher the mechanism for chronic progression.

Genetics of Multiple Sclerosis: An Overview and New Directions

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

Genetic variations in the Dravidian population of South West coast of India: Implications in designing case-control studies

Background & objectives:

Indian data have been largely missing from genome-wide databases that provide information on genetic variations in different populations. This hinders association studies for complex disorders in India. This study was aimed to determine whether the complex genetic structure and endogamy among Indians could potentially influence the design of case-control studies for autoimmune disorders in the south Indian population.

Methods:

A total of 12 single nucleotide variations (SNVs) related to genes associated with autoimmune disorders were genotyped in 370 healthy individuals belonging to six different caste groups in southern India. Allele frequencies were estimated; genetic divergence and phylogenetic relationship within the various caste groups and other HapMap populations were ascertained.

Results:

Allele frequencies for all genotyped SNVs did not vary significantly among the different groups studied. Wright's F_ST was 0.001 per cent among study population and 0.38 per cent when compared with Gujarati in Houston (GIH) population on HapMap data. The analysis of molecular variance results showed a 97 per cent variation attributable to differences within the study population and <1 per cent variation due to differences between castes. Phylogenetic analysis showed a separation of Dravidian population from other HapMap populations and particularly from GIH population.

Interpretation & conclusions:

Despite the complex genetic origins of the Indian population, our study indicated a low level of genetic differentiation among Dravidian language-speaking people of south India. Case-control studies of association among Dravidians of south India may not require stratification based on language and caste.

Comparative genomics of the human, macaque and mouse major histocompatibility complex

The MHC is a highly polymorphic genomic region that encodes the transplantation and immune regulatory molecules. It receives special attention for genetic investigation because of its important role in the regulation of innate and adaptive immune responses and its strong association with numerous infectious and/or autoimmune diseases. The MHC locus was first discovered in the mouse and for the past 50 years it has been studied most intensively in both mice and humans. However, in recent years the macaque species have emerged as some of the more important and advanced experimental animal models for biomedical research into MHC with important human immunodeficiency virus/simian immunodeficiency virus and transplantation studies undertaken in association with precise MHC genotyping and haplotyping methods using Sanger sequencing and next-generation sequencing. Here, in this special issue on 'Macaque Immunology' we provide a short review of the genomic similarities and differences among the human, macaque and mouse MHC class I and class II regions, with an emphasis on the association of the macaque class I region with MHC polymorphism, haplotype structure and function.

Association of EVI5 rs11808092, CD58 rs2300747, and CIITA rs3087456 polymorphisms with multiple sclerosis risk: A meta-analysis

Purpose

Multiple sclerosis (MS) is a major demyelinating disease of the central nervous system with a strong genetic component. Previous studies have reported that the association of EVI5 rs11808092, CD58 rs2300747, and CIITA rs3087456 polymorphisms with the susceptibility to MS. However, the results were inconsistent. Thus, we conducted this meta-analysis to provide a more accurate estimation of the association between any of these polymorphisms and MS risk.

Methods

The PubMed, Embase, Chinese National Knowledge Infrastructure, Wan Fang databases and MSGene were used to search all potentially relevant studies. The odds ratio (OR) with 95% confidence interval (CI) was used to investigate the associations between these three polymorphisms and MS risk.

Results

16 independent case–control studies from 12 publications were finally included into this meta-analysis. The results showed that EVI5 rs11808092 polymorphism was related with increasing the development of MS under five genetic models (allelic: OR = 1.17, 95% CI = 1.10–1.24, P < 0.01; homozygous: OR = 1.37, 95% CI = 1.18–1.59, P < 0.01; heterozygous: OR = 1.16, 95% CI = 1.07–1.26, P < 0.01; recessive: OR = 1.28, 95% CI = 1.11–1.48, P < 0.01; and dominant: OR = 1.19, 95% CI = 1.11–1.48, P < 0.01). CD58 rs2300747 polymorphism was found to be associated with decreasing MS risk in three genetic models (allelic: OR = 0.86, 95% CI = 0.78–0.94, P < 0.01; heterozygous: OR = 0.85, 95% CI = 0.76–0.94, P < 0.01, and dominant: OR = 0.84, 95% CI = 0.76–0.93, P < 0.01). However, this meta-analysis indicated that CIITA rs3087456 polymorphism was not related to multiple sclerosis.

Conclusions

The mutant alleles of EVI5 rs11808092 polymorphism may increase the susceptibility to MS while those of CD58 rs2300747 polymorphism may decrease MS risk. In addition, CIITA rs3087456 polymorphism might not be associated with MS.

European multiple sclerosis risk variants in the south Asian population

BACKGROUND

In less than a decade, genomewide association studies have identified over 100 single-nucleotide variants that are associated with increased risk of developing multiple sclerosis. However, since these studies have focused almost exclusively on European populations, it is unclear what role these variants might play in determining risk in other ethnic groups.

OBJECTIVE

To assess the effects of European multiple sclerosis-associated risk variants in the south Asian population.

METHODS

Using a combination of chip-based genotyping and next-generation sequencing, we have assessed 109 European-associated variants in a total of 270 cases and 555 controls from the south Asian population.

RESULTS

We found that two-thirds of the tested variants (72/109) showed over representation of the European risk allele in south Asian cases (p < 0.0003). In the rest of the Immunochip array, the most associated variant was rs7318477 which maps close to TNFSF13B, the gene for the B-cell-related protein BAFF.

CONCLUSION

Our data indicate substantial overlap in genetic risk architecture between Europeans and south Asians and suggest that the aetiology of the disease may be largely independent of ethnicity.

CD6 gene polymorphism rs17824933 is associated with multiple sclerosis in Indian population

Background:

Multiple sclerosis (MS) prevalence has increased worldwide. The known genetic association for MS in the west has not been studied in detail in nonwhite populations and particularly Indians.

Objective:

The objective of this study was to evaluate some known genetic variations outside the major histocompatibility complex (MHC) region associated with MS in patients of Indian origin.

Materials and Methods:

We investigated 10 gene-associated single nucleotide polymorphisms (SNP's) outside the MHC region in 300 patients and 720 unrelated controls. Genotyping was performed on an ABI7500 real-time polymerase chain reaction genotyping platform using predesigned TaqMan SNP genotyping assays.

Results:

CD6 gene associated SNP (rs17824933) showed significant association with MS (P = 4.2 × 10⁻⁵, odds ratio [OR] = 2.24, confidence interval (CI) = 1.51–3.33). A modest association was also noted for TMEM39A rs1132200 (P = 0.023, OR = 1.41, CI = 1.05–1.91) and IL2RA rs2104286 (P = 0.04, OR = 1.3, CI = 1.006–1.67). In the remaining SNPs, the allele frequencies were overexpressed in patients when compared to healthy controls.

Conclusion:

Our data illustrate the similarity in risk association between Indian and European populations for MS.

Epidemiology and genetic aspects of multiple sclerosis in India

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system with a complex pathophysiology. Considered a rare disease in India in the past, studies over time suggest an increase in subjects with MS in India, although the observations are limited by the lack of formally conducted epidemiological studies and the absence of a nationwide registry. The current World Health Organization (WHO) Multiple Sclerosis International Federation (MSIF) “Atlas of MS” 2013 estimates a prevalence rate of 5-20 per 100,000, which also seems an underestimate. Although there have been reports of phenotypic differences between MS in Indians and the Western counterparts, recent studies report a reasonable similarity in disease types and characteristics. A few studies on the genetics of MS have been reported, including human leukocyte antigen (HLA) associations and non-major histopathology complex (MHC) disease loci. The current review discusses the pivotal studies of the past, newer observations on MS from India, and the need for a national registry.

MS in South Asians in England: early disease onset and novel pattern of myelin autoimmunity

BACKGROUND

Epidemiological studies describe a latitude gradient for increased MS prevalence and a preponderance of disease in Caucasian individuals. However, individuals from other ethnic backgrounds and low-risk regions can acquire a raised risk through migration. Nearly a fifth of the London population is of Asian/Asian-British origin and a significant proportion of referrals are from this group.

METHODS

We investigated whether there were differences in timing, presentation, severity, and immunology of disease (with respect to CD4 myelin epitope recognition) between individuals in London with MS who were either of S. Asian or Caucasian origin. Individuals of S. Asian origin with MS were compared with healthy S. Asian controls, individuals with MS and of Caucasian origin and Caucasian controls.

RESULTS

Age at MS onset is significantly lower in the S. Asian group, attributable to earlier onset specifically in UK-born individuals, though clinical presentation is similar. Analysis of CD4 autoimmunity to myelin antigens shows disease in S. Asian individuals to encompass recognition of novel epitopes; immunity to MBP116-130 in S. Asian individuals was highly disease-specific.

CONCLUSIONS

These findings emphasize the need to define disease profiles across ethnicities and identify environmental triggers conferring acquired risk. Such findings must inform choices for immunotherapeutic interventions suitable for all, across ethnicities.

HLA associations in South Asian multiple sclerosis

Background:

Previous efforts to identify Human Leukocyte Antigen (HLA) gene associations with multiple sclerosis (MS) in the South Asian population have been underpowered.

Aim:

To identify the primary HLA class II alleles associated with MS in Indians.

Methods:

We typed HLA-DRB1, -DQA1 and -DQB1 in 419 patients and 451 unrelated controls by polymerase chain reaction using sequence specific oligonucleotide probes (PCR-SSOP).

Results:

At the gene level DRB1 showed significant evidence of association ( p=0.0000012), DQA1 showed only marginal evidence of association ( p=0.04) and there was no evidence for association at DQB1 ( p=0.26). At the DRB1 locus association is confirmed with the *15:01 ( p=0.00002) and the *03 ( p=0.00005) alleles.

Conclusion:

Our study confirms that the risk effects attributable to the HLA- DRB1*15:01and DRB1*03 alleles seen in Europeans are also seen in Indians. The absence of any evidence of association with DQB1 alleles reflects the lower linkage disequilibrium between DQB1 alleles and DRB1 risk alleles present in this population, and illustrates the potential value of fine mapping signals of association in different ethnic groups.

Environmental factors related to multiple sclerosis in Indian population

BACKGROUND

Multiple sclerosis (MS) is less prevalent among Indians when compared to white populations. Genetic susceptibility remaining the same it is possible that environmental associations may have a role in determining disease prevalence.

AIMS

To determine whether childhood infections, vaccination status, past infection with Helicobacter pylori (H.pylori), diet, socioeconomic and educational status were associated with MS.

MATERIAL AND METHODS

139 patients and 278 matched control subjects were selected. A validated environmental exposure questionnaire was administered. Estimation of serum H.pylori IgG antibody was done by ELISA. Patients and controls were genotyped for HLA-DRB1*15:01.

RESULTS

In our cohort a significant association was seen with measles (p < 0.007), vegetarian diet (p < 0.001, higher educational status (p < 0.0001) and urban living (p < 0.0001). An inverse relationship was seen with H.Pylori infection and MS (p < 0.001). Measles infection (OR 6.479, CI 1.21-34.668, p < 0.029) and high educational status (OR 3.088, CI 1.212-7.872, p < 0.018) were significant risk factors associated with MS. H.pylori infection was inversely related to MS (OR 0. 319, CI 0.144- 0.706, p < 0.005).

CONCLUSIONS

Environmental influences may be important in determining MS prevalence.

An ImmunoChip study of multiple sclerosis risk in African Americans

The aims of this study were: (i) to determine to what degree multiple sclerosis-associated loci discovered in European populations also influence susceptibility in African Americans; (ii) to assess the extent to which the unique linkage disequilibrium patterns in African Americans can contribute to localizing the functionally relevant regions or genes; and (iii) to search for novel African American multiple sclerosis-associated loci. Using the ImmunoChip custom array we genotyped 803 African American cases with multiple sclerosis and 1516 African American control subjects at 130 135 autosomal single nucleotide polymorphisms. We conducted association analysis with rigorous adjustments for population stratification and admixture. Of the 110 non-major histocompatibility complex multiple sclerosis-associated variants identified in Europeans, 96 passed stringent quality control in our African American data set and of these, >70% (69) showed over-representation of the same allele amongst cases, including 21 with nominally significant evidence for association (one-tailed test P < 0.05). At a further eight loci we found nominally significant association with an alternate correlated risk-tagging single nucleotide polymorphism from the same region. Outside the regions known to be associated in Europeans, we found seven potentially associated novel candidate multiple sclerosis variants (P < 10(-4)), one of which (rs2702180) also showed nominally significant evidence for association (one-tailed test P = 0.034) in an independent second cohort of 620 African American cases and 1565 control subjects. However, none of these novel associations reached genome-wide significance (combined P = 6.3 × 10(-5)). Our data demonstrate substantial overlap between African American and European multiple sclerosis variants, indicating common genetic contributions to multiple sclerosis risk.

GWAS-identified multiple sclerosis risk loci involved in immune response: validation in Russians

Multiple sclerosis (MS) is a chronic neuro-inflammatory disease of complex etiology. The results of GWAS, a high-throughput method to discover genetic architecture of MS, require replication in independent ethnic groups. We performed a replication study of nine GWAS-identified SNPs in immune response in Russians. Associations of CLEC16A and IL2RA with MS were validated. Besides, we observed the associations of CLEC16A and IRF8 in women, and IL7RA and CD58 in men. With multi-locus association analysis two protective biallelic combinations: (TNFRSF1A*T+CLEC16A*A) and (TNFRSF1A*T+IRF8*A) were identified in women. Associations of CLEC16A*G/G and both biallelic combinations in women with MS survived the permutation test.

IL2RA Allele Increases Risk of Neuromyelitis Optica in Southern Han Chinese

Background:

Neuromyelitis optica (NMO) and multiple sclerosis (MS) are chronic neuro-inflammatory diseases believed to arise from complex interactions between environmental and genetic factors. Recently, single nucleotide polymorphisms (SNPs) in interleukin (IL)-2 and -7 receptor alpha genes have been identified as novel susceptibility alleles for MS in genome-wide association studies. However, similar research on NMO is limited. We aimed to investigate the association of IL2RA SNPs rs2104286 and rs12722489 and IL7RA SNP rs6897932 with Southern Han Chinese NMO and MS patients.

Methods:

Frequencies of the three SNPs were examined in Southern Han Chinese mS cases (n=78), NMS cases (n=67) and controls (n=133) using sequencing-based typing.

Results:

The rs2104286G frequency in the IL2RA gene was significantly higher in NMO patients than in controls (puncorr=0.013, pcorr=0.026, OR:1.942, 95%CI:1.146-3.291).

Conclusion:

The rs2104286 G allele in IL2RA is present at higher frequencies in NMO patients than in healthy controls within a Southern Han Chinese population.

The influence of non-HLA gene polymorphisms and interactions on disease risk in a Western Australian multiple sclerosis cohort

Non-Human Leukocyte Antigen (HLA) genes have concomitant, although modest, effects on multiple sclerosis (MS) susceptibility; however findings have varied in different populations. Here we present the results of an association study of 16 single nucleotide polymorphisms (SNPs) in 10 non-HLA genes (IL7R, IL2RA, CLEC-16A, TYK2, CD58, IRF5, STAT3, CTLA-4, APOE, ICAM-1) in a Western Australian cohort of 350 MS patients and 498 population control subjects. Our results indicate that in this population, SNPs in IL7R, TYK2, IRF5 and APOE have modifying effects on MS susceptibility. We also found evidence of interactive protective effects between polymorphisms in the IL7R/CD58, CLEC-16A/CTLA-4, and TYK2/IRF5 genes, which in some instances are restricted within HLA- or gender-defined groups.

From Identification to Characterization of the Multiple Sclerosis Susceptibility Gene CLEC16A

Multiple sclerosis (MS) is an inflammatory, demyelinating disorder of the central nervous system that develops in genetically susceptible individuals, probably triggered by common environmental factors. Human leukocyte antigen (HLA) loci were early shown to confer the strongest genetic associations in MS. Now, more than 50 non-HLA MS susceptibility loci are identified, of which the majority are located in immune-regulatory genes. Single nucleotide polymorphisms (SNPs) in the C-type lectin-like domain family 16A (CLEC16A) gene were among the first non-HLA genetic variants that were confirmed to be associated with MS. Fine-mapping has indicated a primary association in MS and also other autoimmune diseases to intronic CLEC16A SNPs. Here, we review the identification of MS susceptibility variants in the CLEC16A gene region, functional studies of the CLEC16A molecule and the recent progress in understanding the implications thereof for MS development. This may serve as an example of the importance for further molecular investigation of the loci identified in genetic studies, with the aim to translate this knowledge into the clinic.

Association of Epstein-Barr virus infection with multiple sclerosis in India

OBJECTIVES

Epstein-Barr virus (EBV) seroprevalence is high from early childhood in Indian populations, though multiple sclerosis (MS) is uncommon. The present study aims to evaluate the association of EBV infection with MS in Indian patients.

METHOD

In this study 140 MS patients and equal number of matched controls were included. Estimation of serum Immunoglobin G (IgG) for EBV Nuclear antigen 1 (EBNA1), viral capsid antigen (EBV-VCA) and early antigen (EB-EA) were obtained by quantitative enzyme linked immunosorbent assay (ELISA). Patients and controls were genotyped for the human leukocyte antigen (HLA) DRB1*1501 allele.

RESULTS

A modest difference was observed for EBNA1 (p=0.02) and EBV-VCA (p=0.03) titres in MS patients as compared to healthy controls. There was no association between EBNA1 titres and MS. High EBNA1 titre (>99.75U/l) was significantly associated with HLA DRBI*15:01 (OR=4.92. CI=1.07-22.57) status in MS patients but not in healthy controls (OR=1.19, CI=0.53-2.63).

CONCLUSION

Evidence for a strong association with remote EBV infection was lacking in this study of Indian patients with MS. Patients who are carriers of HLA DR15 allele may have high EBNA1 titres. These preliminary results need to be reproduced in an independent and larger dataset.

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

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

Association between the CD226 rs763361 polymorphism and susceptibility to autoimmune diseases: a meta-analysis

OBJECTIVE

The aim of this study was to explore whether the CD226 rs763361 polymorphism confers susceptibility to autoimmune diseases.

METHODS

A meta-analysis was conducted on the associations between the CD226 rs763361 polymorphism and autoimmune diseases using: 1) allele contrast, and 2) the recessive, 3) dominant and 4) additive models.

RESULTS

Ten articles that included 17 comparative studies on a total of 8900 patients and 10,295 controls were included in the meta-analysis. These studies were performed on seven European, five Asian and five South American sample populations. Meta-analysis of all study subjects revealed an association between the CD226 rs763361 T allele and the susceptibility to autoimmune diseases (odds ratio; OR 1.162, 95% confidence interval; CI 1.097-1.230, p < 1.0 × 10(-8)). Stratification by ethnicity indicated an association between the CD226 rs763361 T allele and autoimmune disease in Europeans and South Americans (OR 1.134, 95% CI 1.079-1.191, p = 6.7 × 10(-7); OR 1.308, 95% CI 1.160-1.475, p = 1.1 × 10(-5)) and between the CD226 rs763361 TT genotype and autoimmune disease in Asians (OR 1.366, 95% CI 1.130-1.650, p = 0.001). Disease-specific meta-analysis showed an association between systemic lupus erythematosus (SLE) and the CD226 rs763361 T allele (OR 1.150, 95% CI 1.040-1.271, p = 0.006), but no association between rheumatoid arthritis and the CD226 rs763361 polymorphism (OR for the T allele 1.207, 95% CI 0.913-1.596, p = 0.187). On the other hand, associations were found between the CD226 rs763361 T allele and systemic sclerosis (SSc) and type 1 diabetes (T1D) (OR 1.126, 95% CI 1.020-1.244, p = 0.019; OR 1.353, 95% CI 1.102-1.660, p = 0.004).

CONCLUSIONS

This meta-analysis demonstrates the CD226 rs763361 polymorphism confers susceptibility to autoimmune disease in Europeans, South Americans and Asians, and in particular, shows that the CD226 rs763361 polymorphism is associated with SLE, SSc and T1D. These results support the existence of an association between the CD226 gene and a subgroup of autoimmune diseases.

The human IL-7 receptor gene: deletions, polymorphisms and mutations

Most T cell subsets depend on IL-7 for survival. IL-7 binds to IL-7Rα and γc, initiating the signaling cascade. Deletion of IL-7Ra in humans has, for some time, been known to cause severe combined immunodeficiency. More recently, polymorphisms in IL-7R have been shown be a risk factor for a number of diseases that are autoimmune or involve excess immune and inflammatory responses including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, primary biliary cirrhosis, inflammatory bowel disease, atopic dermatitis, inhalation allergy, sarcoidosis and graft-versus host disease. The polymorphism that affects risk to most of these immunopathologies is T244I at the border of the extracellular domain and the transmembrane region. The same region has recently been shown to harbor gain-of-function mutations in acute lymphoblastic leukemia. These studies have suggested new therapies that target the IL-7 pathway.

A nationwide survey of the prevalence of multiple sclerosis in immigrant populations of Sweden

BACKGROUND

In 2008, immigrants constituted 14% of the population of Sweden, a high-risk area for multiple sclerosis (MS). We investigated the largest Swedish immigrant populations for the prevalence of MS.

METHOD

Data on foreign-born MS patients were retrieved from Swedish national health and population registers. We calculated observed versus expected numbers of MS patients and gender- and age-specific prevalence ratios (PR) between immigrant populations and the general population of Sweden and, where possible, of the countries of birth.

RESULTS

The 19 largest immigrant populations included 1327 MS patients. The global variation in MS prevalence was reflected in Sweden. The prevalence in immigrant populations who had moved to Sweden from countries with a lower MS risk was however higher than in their countries of birth. Notably, the MS prevalence in the population born in Iran was at least as high as in the general population of Sweden (men: PR = 1.10, 95% CI 0.81-1.46, p = 0.537, women: PR = 1.18, 95% CI 0.97-1.44, p = 0.855) and more than twice as high as in Isfahan, Iran (men: PR = 3.06 (95% CI 2.26-4.06), p <0.001, women: PR = 2.21 (95% CI 1.81-2.68), p <0.001).

CONCLUSIONS

The MS prevalence increased in migrants who moved to Sweden from countries with a lower MS risk. In the Iranian immigrant population the prevalence exceeded that in the general population of Sweden. This indicates that Iranians carry genetic factors that contribute to a higher MS risk when environmental-lifestyle MS risk factors change.

Insights into the changing perspectives of multiple sclerosis in India

Multiple Sclerosis (MS) is being diagnosed in increasing numbers in metropolitan cities of India for which the availability of specialist neurologists and magnetic resonance imaging (MRI) facilities are primarily responsible. Epidemiological data are unavailable. Existing data have been obtained from small often retrospective studies from different parts of the country. These earlier studies suggested that optic nerve and spinal cord involvement are considerably high, and that perhaps optic spinal MS was the most prevalent form in India. On this basis it was also speculated that neuromyelitis optica (NMO) may be overrepresented in Indians. However in recent times, prospective studies backed by MRI data have shown no distinct differences between MS seen in the west and India. Sero positivity for NMO IgG is low though NMO phenotype disorders constitute nearly 20% of demyelinating disorders in India. Genetic susceptibility for MS among Indians may be similar to that for white populations. In the major histocompatibility complex (MHC), HLA DR1∗1501 has been strongly associated with MS in Indians. A recent study that evaluated the established non-MHC multiple sclerosis loci in a small data set of Indian patients suggested a strong similarity with white populations. This review highlights some of the background information available on MS from India and so also some recent studies that unveiled the disease characteristics in Indian patients.