Although scientists don’t fully understand what causes multiple sclerosis (MS), they believe that genetic and environmental factors play a role in its development. Research shows that genetics may account for about 54 percent of the risk for developing MS, with the remaining risk likely tied to environmental factors.

MS is an autoimmune disease, meaning the immune system mistakenly targets the body’s own tissues. In MS, the immune system harms the protective myelin sheath around nerve cells in the central nervous system. This damage leads to lesions in the brain, spinal cord, and optic nerves, making it hard for nerve cells to work properly.

Although the specific causes of MS are still unknown, science has come a long way. With the development of genome-wide association studies (GWAS), scientists have been able to link certain genes to a higher risk of developing MS.

What Genes Are Associated With MS?

Multiple GWAS studies have identified more than 110 genes associated with the risk of MS. Some genes are more relevant than others and are associated with a higher risk factor for the condition.

HLA-DRB1

HLA-DRB1*15:01, a version of the HLA-DRB1 gene, is one of the most strongly linked genes to MS. A person with the HLA-DRB1*15:01 gene is three times as likely to develop MS as someone without this version of the gene.

HLA-DRB1 is one of several human leukocyte antigens (HLAs). These genes help T cells, a type of white blood cell, recognize harmful proteins on the surface of invading cells, like bacteria or viruses. Once T cells detect these proteins, they either destroy the invaders or signal other immune cells to join the attack.

The HLA genes are diverse, and there are many different versions of each gene, called alleles. Scientists have yet to understand why the expression of the HLA-DRB1*15:01 allele is associated with a greater risk for MS. However, MS is an autoimmune disease, and HLA-DRB1*15:01 plays an important role in activating immune cells. It may be that this gene has something to do with the activation of immune cells against the CNS.

L7R-Alpha and IL2R-Alpha

Other genes that increase the risk of MS are also related to how the immune system works. These include the IL7R-alpha and IL2R-alpha genes. “IL” stands for “interleukin,” a type of protein that helps immune cells communicate and control the body’s response to infections and diseases.

The L7R-alpha and IL2R-alpha genes help create receptors on cell surfaces. These receptors are proteins that allow cells to receive signals, like those from cytokines, which guide the immune system’s response to infections or injury. Scientists have identified small genetic changes, called single nucleotide polymorphisms (SNPs), in the IL7R-alpha and IL2R-alpha genes. These changes affect how the receptors work, and people with these SNPs have a 1.5 times higher chance of developing MS.

Is MS Hereditary?

Although there are some genetic associations with MS, the disease itself is not technically hereditary. Unlike hereditary conditions that follow a specific pattern within families, MS doesn’t show this type of consistency.

However, MS still has some genetic components. Blood relatives may have a higher risk of developing MS when a family member has it. For example, a sibling or child of someone with MS may have up to a 4 percent chance of developing MS — a risk 10 to 20 times higher than that of the general population. The identical twin of someone with MS is at even higher risk, with a 30 percent chance of developing the disease. Because identical twins share all genetic material, the fact that a twin’s risk is not 100 percent affirms that factors other than genetics play a role in MS.

Learn more about who is likely to develop MS.

Talk to Your Doctor

Research has found key genes, like HLA-DRB1*15:01, that raise the risk of MS, but the disease isn’t purely genetic. Factors like the immune system and environment also play a role. Ongoing studies on these genetic links may lead to better ways to diagnose and treat MS. If you have questions about MS, talk to your doctor. They can give you advice and guide you through the next steps.

Find Your Team

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