Published: 29-09-2013 00:00 | Updated: 29-10-2014 10:32

Another 48 genetic variants associated with MS

An international consortium of scientists has identified an additional 48 genetic variants influencing the risk of developing multiple sclerosis, MS. This work, which is presented in the journal Nature Genetics, nearly doubles the number of known genetic risk factors associated with MS – and thereby provides additional key insights into the biology of this debilitating neurological condition, globally affecting millions of people.

The study was conducted within the framework of the International Multiple Sclerosis Genetics Consortium (IMSGC), and coordinated from the Miller School of Medicine at University of Miami. Researchers from 84 research groups in 13 countries, of which several from Karolinska Institutet, participated in the work. The genes implicated by the newly identified associations underline the central role played by the immune system in the development of multiple sclerosis and show substantial overlap with genes known to be involved in other autoimmune diseases.

The present study takes advantage of custom designed technology known as ImmunoChip - a high-throughput genotyping array specifically designed to interrogate a targeted set of genetic variants linked to one or more autoimmune diseases. IMSGC researchers used the ImmunoChip platform to analyze the DNA from 29,300 individuals with multiple sclerosis and 50,794 unrelated healthy controls, making this the largest genetics study ever performed for MS. In addition to identifying 48 new susceptibility variants, the study also confirmed and further refined a similar number of previously identified genetic associations. With these new findings, there are now 110 genetic variants associated with MS.

"Although each of these variants individually confers only a very small risk of developing multiple sclerosis, collectively they explain approximately 20% of the genetic component of the disease", says Professor Tomas Olsson at the Department of Clinical Neuroscience, Karolinska Institutet, who coordinated the Swedish part of the study.

MS is a chronic disabling neurological condition that affects over 2.5 million individuals worldwide. The disease results in patchy inflammation and damage to the central nervous system that causes problems with mobility, balance, sensation and cognition depending on the location of the changes. Neurological symptoms are often intermittent in the early stages of the disease but tend to become persistent and progressively worsen with the passage of time for the majority of patients. The risk of developing multiple sclerosis is increased in those who have a family history of the disease.

The Swedish part of the study was funded by grants from the Swedish Research Council, Knut and Alice Wallenberg Foundation, AFA Insurance, and the Swedish Brain Foundation. In all, the study was funded by more than 40 local and national agencies and foundations. Tomas Olsson is also affiliated to the Center for Molecular Medicine, a collaboration between Karolinska Institutet and Karolinska University Hospital.