Perspectives on the use of multiple sclerosis risk genes for prediction

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.

Predicting Multiple Sclerosis: Challenges and Opportunities

Determining effective means of preventing Multiple Sclerosis (MS) relies on testing preventive strategies in trial populations. However, because of the low incidence of MS, demonstrating that a preventive measure has benefit requires either very large trial populations or an enriched population with a higher disease incidence. Risk scores which incorporate genetic and environmental data could be used, in principle, to identify high-risk individuals for enrolment in preventive trials. Here we discuss the concepts of developing predictive scores for identifying individuals at high risk of MS. We discuss the empirical efforts to do so using real cohorts, and some of the challenges-both theoretical and practical-limiting this work. We argue that such scores could offer a means of risk stratification for preventive trial design, but are unlikely to ever constitute a clinically-helpful approach to predicting MS for an individual.

Pattern Recognition Receptors in Multiple Sclerosis and Its Animal Models

Pattern recognition receptors (PRRs) coordinate the innate immune response and have a significant role in the development of multiple sclerosis (MS). Accumulating evidence has identified both pathogenic and protective functions of PRR signaling in MS and its animal model, experimental autoimmune encephalomyelitis (EAE). Additionally, evidence for PRR signaling in non-immune cells and PRR responses to host-derived endogenous ligands has also revealed new pathways controlling the development of CNS autoimmunity. Many PRRs remain uncharacterized in MS and EAE, and understanding the distinct triggers and functions of PRR signaling in CNS autoimmunity requires further investigation. In this brief review, we discuss the diverse pathogenic and protective functions of PRRs in MS and EAE, and highlight major avenues for future research.

The combined effect of IL-17F and CCL20 gene polymorphism in susceptibility to multiple sclerosis in Egypt

BACKGROUND

Levels of CCL20 and its CCR6 receptor are elevated in many autoimmune diseases which help in the recruitment of T helper (Th17) cells to site of inflammation.

OBJECTIVES

Determine the value of single nucleotide polymorphism of CCL20 (rs6749704) and IL-17F (rs763780) genes and their concomitant effect on the serum CCL20 level and susceptibility to MS in Egyptian patients.

SUBJECTS AND METHODS

Blood samples were collected from 83 patients and 95 healthy subjects. Serum levels of CCL20 were measured by ELISA. The DNA was analyzed for rs6749704 and rs763780 using Genotyping Taqman assay.

RESULTS

The mean serum levels of CCL20 in the MS group were significantly higher than healthy group (P < 0.001). Frequencies of CT genotype of rs6749704 in CCL20 gene and C allele in MS patients were significantly higher compared to controls. Also significant increase of rs763780 in IL-17F gene was detected in MS patients. Concomitant polymorphism in both genes in MS patients showed an increase risk to MS rather than individual locus.

CONCLUSION

CCL20 may play an important role in the pathogenesis of MS. Both allelic variation of (rs6749704) within CCL20 gene and (rs763780) within IL-17F gene can be considered risk factor for development of MS in Egyptian patients.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

Genetic association of rs1520333 G/A polymorphism in the IL7 gene with multiple sclerosis susceptibility in Isfahan population

Background:

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease in which the insulating membrane of central nervous system is damaged. The etiology of MS includes both genetic and environmental causes. A Genome — Wide Association Study (GWAS) recognized genetic single nucleotide polymorphisms (SNP) linked with MS predisposition among which immunologically related genes are considerably over signified. The purpose of the present study is to explore the association of rs1520333 C/T polymorphism in the IL7 gene variants with the risk of MS in a subset of Iranian population.

Materials and Methods:

In this case — control study, 110 cases with MS and 110 controls were contributed. DNA was extracted from blood samples and to amplify the fragment of interest contain rs1520333 SNP, polymerase chain reaction — restriction fragment length polymorphism method was implemented for genotyping of the DNA samples with a specific restriction enzyme (MwoI).

SPSS for Windows software (version 18.0; SPSS, Chicago, IL, USA) was used for statistical analysis.

Result:

We demonstrated the important association between G allele [odds ratio (OR) =1.6614, confidence interval (CI) =1.12-2.47, P = 0.0124] and GG genotype (OR = 7.45, 95% CI = 2.13-25.97, P 0.0016) of the rs1520333 SNP for susceptibility to MS after adjustment for age, and gender. OR adjusted for age, gender, and body mass index has displayed similar outcomes.

Conclusion:

These results indicate that the rs1520333 SNP is a significant susceptibility gene variant for development of MS in the Iranian population. Nevertheless, functional studies are required to completely elucidate how this SNP contributed to MS pathogenesis.

Variants of CYP27B1 are associated with both multiple sclerosis and neuromyelitis optica patients in Han Chinese population

Multiple sclerosis (MS) and neuromyelitis optica (NMO) are chronic demyelinating diseases of the central nervous system (CNS). Recently, variants of vitamin D metabolizing genes, including rs12368653, rs10876994, rs118204009 and rs703842 in CYP27B1, and rs2248359 in CYP24A1 have been identified to be associated with the pathogenicity of MS in Caucasian populations. However, these results have not been replicated in Han Chinese population. Here we investigated the association of these variants with MS and NMO susceptibility in 149 MS patients, 110 NMO patients and 294 healthy controls using MassARRAY system and Sanger sequencing. We found that the frequencies of the A allele of rs703842 were higher in MS patients than controls (p=0.032), and statistical differences were observed in the genotypes of both rs703842 (p=0.013) and rs10876994 (p=0.001) between NMO patients and controls. In addition, we found difference in the genotype of rs12368653 between MS patients and controls (p=0.008). However, no difference was found in rs2248359 among these three groups. The reported rare mutation p.R389H (rs118204009) was not found in our study. In conclusion, our study suggested that variants of CYP27B1 were associated with both MS and NMO patients in Han Chinese population.

Genetic burden of common variants in progressive and bout-onset multiple sclerosis

BACKGROUND

The contribution of genetic variants underlying the susceptibility to different clinical courses of multiple sclerosis (MS) is still unclear.

OBJECTIVE

The aim of the study is to evaluate and compare the proportion of liability explained by common SNPs and the genetic burden of MS-associated SNPs in progressive onset (PrMS) and bout-onset (BOMS) cases.

METHODS

We estimated the proportion of variance in disease liability explained by 296,391 autosomal SNPs in cohorts of Italian PrMS and BOMS patients using the genome-wide complex trait analysis (GCTA) tool, and we calculated a weighted genetic risk score (wGRS) based on the known MS-associated loci.

RESULTS

Our results identified that common SNPs explain a greater proportion of phenotypic variance in BOMS (36.5%±10.1%) than PrMS (20.8%±6.0%) cases, and a trend of decrease was observed when testing primary progressive (PPMS) without brain MRI inflammatory activity (p = 7.9 × 10(-3)). Similarly, the wGRS and the variance explained by MS-associated SNPs were higher in BOMS than PPMS in males (wGRS: 6.63 vs 6.51, p = 0.04; explained variance: 4.8%±1.5% vs 1.7%±0.6%; p = 0.05).

CONCLUSIONS

Our results suggest that the liability of disease is better captured by common genetic variants in BOMS than PrMS cases. The absence of inflammatory activity and male gender further raise the difference between clinical courses.

Multiple sclerosis: individualized disease susceptibility and therapy response

Multiple sclerosis (MS) is a heterogeneous disease in which diverse genetic, pathological and clinical backgrounds lead to variable therapy response. Accordingly, MS care should be tailored to address disease traits unique to each person. At the core of personalized management is the emergence of new knowledge, enabling optimized treatment and disease-modifying therapies. This overview analyzes the promise of genetic and nongenetic biomarkers in advancing decision-making algorithms to assist diagnosis or in predicting the disease course and therapy response in any given MS patient.

How can polygenic inheritance be used in population screening for common diseases?

Advances in genomics have near-term impact on diagnosis and management of monogenic disorders. For common complex diseases, the use of genomic information from multiple loci (polygenic model) is generally not useful for diagnosis and individual prediction. In principle, the polygenic model could be used along with other risk factors in stratified population screening to target interventions. For example, compared to age-based criterion for breast, colorectal, and prostate cancer screening, adding polygenic risk and family history holds promise for more efficient screening with earlier start and/or increased frequency of screening for segments of the population at higher absolute risk than an established screening threshold; and later start and/or decreased frequency of screening for segments of the population at lower risks. This approach, while promising, faces formidable challenges for building its evidence base and for its implementation in practice. Currently, it is unclear whether or not polygenic risk can contribute enough discrimination to make stratified screening worthwhile. Empirical data are lacking on population-based age-specific absolute risks combining genetic and non-genetic factors, on impact of polygenic risk genes on disease natural history, as well as information on comparative balance of benefits and harms of stratified interventions. Implementation challenges include difficulties in integration of this information in the current health-care system in the United States, the setting of appropriate risk thresholds, and ethical, legal, and social issues. In an era of direct-to-consumer availability of personal genomic information, the public health and health-care systems need to prepare for an evidence-based integration of this information into population screening.