Using extremely fine-grained analytical tools, scientists compared genetic information in three sets of identical twins. One of each pair had Multiple Sclerosis, and the other didn’t — yet their genes proved essentially identical. The research cost $1.5 million, and the scientists took 18 months to sequence 2.8 billion DNA units in each twin, and determine whether they came from the mother or father. Most genomic comparisons look for differences in a just handful of suspect genes, and even whole-genome approaches don’t differentiate between parental contributions. The researchers also analyzed the twins' CD4 cells because of their central role in the development of MS. The absence of genetic differences doesn’t mean that genetics are irrelevant to multiple sclerosis. Identical twins, who are descended from the same egg, are six times more likely to develop MS than non-identical twins, who come from two different eggs. It’s still possible that some as-yet-unknown genetic factor, undetectable by even the most advanced tools, may explain the discordance in the study. However, geneticist Stephen Kingsmore thinks the culprit is probably an unknown environmental influence. This unknown factor could combine with other known genetic risks of developing multiple sclerosis. This study was a pioneering effort and the researchers are looking forward to studying more twins and other cells.
After reading this I found some more information about the possible role of genetics in multiple sclerosis. One article called, "Twin study surveys genome for cause of multiple sclerosis," stated that,"There is no doubt that MS has a genetic component. Relatives of people who have the disease have an increased risk of developing it; if a patient with MS has an identical twin, that twin's risk climbs to more than 25 percent." Although this study also reported no difference in the genomes between twins (one with MS and one without) another study I found reported the identification of 2 new genes that are possibly linked to MS. The genes were found by teams of international researchers who looked for genes associated with MS in more than 12,000 people.
ReplyDeleteOne gene that they identified was a variant of IL-7R, which is said to increase the risk of MS by 20-30 percent. This gene is thought to affect the production of IL-7, causing fewer IL-7 receptors to be made, suppressing the activation of the body's immune system, by affecting the maintenance, differentiation and proliferation of immune cells.
The other gene that was identified in this article is IL-2R, which has also been linked to other autoimmune diseases.
The identification of these genes as possible links to MS could lead to more studies about the mechanisms that lead to the development of MS.
Although we have seen that multiple sclerosis could be linked to other factors, such as the environment, it is interesting to see that there is a correlation between genetics and the development of MS.