genetic variants

Genetic Variants in Inflammasome Genes Influence MS Severity, Progression, Study Suggests

Genetic variants that enhance the activity of the NLRP3 inflammasome or the interleukin-1 beta cytokine are linked to higher severity and progression of multiple sclerosis, a study suggests. Previous studies with mouse models of MS have shown that a complex of innate immune system receptors and sensors, known as the inflammasome, is likely a player promoting the immune systemā€™s attack on the central nervous system in MS and, consequently, the loss of myelin. Follow-up studies showed that people carrying mutations that enhance the function of the NLRP3 inflammasome ā€” one of the three components of the inflammasome complex ā€” had a worse prognosis, once again supporting the role of the inflammasome in MS. Once activated, the inflammasome triggers an enzyme called caspase-1 that promotes the production of two very powerful proinflammatory cytokines called interleukin (IL)-1 betaĀ and IL-18. To further evaluate the role of the inflammasome in MS, a team led by researchers at the Universidade de Sao Paulo in Brazil analyzed the genetic sequence of five inflammasome genesĀ ā€” NLRP1, NLRP3, NLRC4, IL-1 beta, and IL-18 ā€” in blood samples retrieved from 264 patients diagnosed with MS or other demyelinating diseases. They also analyzed 233 healthy individuals used as controls. The team specifically looked at eight variations in certain nucleotides (the building blocks of DNA), called single nucleotide polymorphisms (SNPs). Previous studies reported a link between SNPs in inflammasome-related genes and certain forms of MS. Results showed that SNPs associated with low serum levels of IL-18 were significantly less frequent in MS patients than in controls. In contrast, variants that enhance the function of NLRP3 and IL-1 beta were associated with severity and progression of MS, as measured by the Expanded Disability Status Scale. These results suggest that the "activation of NLRP3 inflammasome could represent a risk factor for MS clinical presentation,ā€ the researchers wrote. A particular variant in the NLRC4Ā gene was less frequent in patients whose disease progressed rapidly compared with those who had a slower disease, an intriguing observation, according to researchers, suggestive of a ā€œprotection effect of this variant against a bad prognosis.ā€ Carriers of this variant also responded better to treatment with interferon-beta. Regarding MS type, the genetic variant that promotes the function of theĀ IL-1 beta gene was significantly more frequent in progressive forms of MS than in relapsing-remittingĀ MS, strengthening once again the negative effects of IL-1 beta in the disease. An analysis of inflammasome activity in blood monocytes, a group of immune cells, showed that the inflammasome is permanently activated in MS compared with healthy controls. "This study emphasizes that a constitutive activation of NLRP3 inflammasome, principally through IL-1 beta production, represents a risk factor for both the development of MS and the progression to severe forms of the disease. On the other hand, low IL-18 production and/or NLRC4 activation were beneficial for MS patients,ā€ the team concluded.

Study Confirms Link Between Mutations in IL-23A Gene and MS Risk

A new study confirmed the involvement of three genetic variants, or mutations, of theĀ interleukin-23A (IL-23A) gene, and one variant of its receptor IL-23R, Ā in the risk of developing multiple sclerosis (MS) and other related inflammatory nervous disorders, together known as inflammatory demyelinating diseases (IDD). Details of this study, ā€œCharacterization of…

Immune System May Harbor Natural Way of Fighting MS, Other Autoimmune Diseases

A variant in theĀ TYK2Ā gene, which encodes an immune system protein, may work to protect people fromĀ autoimmune disorders, including multiple sclerosis (MS), without overly depressing the body’s ability to fight opportunistic infections, researchers at theĀ University of Oxford report. Their study, ā€œResolving TYK2 Locus Genotype-To-Phenotype Differences In Autoimmunity,ā€ was published…

Genome-wide Analysis Pinpoints 200 Gene Variants Common to MS

A genome-wide analysis of over 110,000 peopleĀ allowed researchersĀ withĀ theĀ International Multiple Sclerosis Genetics Consortium (IMSGC)Ā to discoverĀ 200 genetic loci (the position of genes on a chromosome) that areĀ common to peopleĀ withĀ multiple sclerosis (MS). The findings were given in theĀ presentation, ā€œ200 loci complete the genetic puzzle of multiple sclerosis,ā€ by Dr. Nikolaos…

‘Master Switch’ for Autoimmune Diseases Like MS Potentially Seen in DNA of Immune Cells

Regions of DNA calledĀ super-enhancersĀ regulate immune cell activity, including the body’s response to threats like inflammation or pathogens, and now scientists have found that they also harborĀ genetic variantsĀ associated with autoimmune diseases ā€” gene variants that may be the “master switches” for these conditions. The findings were described in the study ā€œ…