Multiple sclerosis (MS) afflicts the central nervous system, causing unpredictable and varying symptoms that differ from person to person. About one in 700 people in the United States is affected by the disease. Although there is currently no cure for MS, there are treatments that can slow the progression of the disease and enhance the quality of life for people who have this condition.
Researchers have identified several genetic variants in the HLA region of the genome —an area containing many genes involved in immune system function — that seem to affect MS symptoms, disease severity, and response to treatment. One of these variants is in the HLA-DRB1 gene. Known as HLA-DRB1*1501, this variant is associated with increased risk for MS, though exactly how it is involved in development of the disease is unclear.
In a report published online today in the journal Archives of Neurology, a team of researchers led by Drs. Madeleine Sombekke and Chris Polman of Vrije University in Amsterdam uncovered a clue which may elucidate the connection between the HLA-DRB1*1501 variant and multiple sclerosis. They analyzed *1501 and other genetic variants in 150 Dutch individuals with multiple sclerosis to see if any of the SNPs were associated with variation in brain and spinal cord lesions.
One SNP in particular, (used as a proxy for HLA-DRB1*1501), was associated with spinal cord lesions. People carrying at least one copy of the A version of had significantly more spinal lesions and had more segments of the spinal cord affected than people with two copies of the G version.
MS is believed to be an autoimmune disorder — wherein the immune system attacks the body’s own cells rather than foreign invaders — and so it makes sense that genetic variants in immune system genes would influence the course of the disease and its clinical features. HLA genes, in particular, encode proteins that contribute to self vs. non-self immune recognition. Previous studies have proposed a link between HLA-DRB1*1501 and disease severity. Since lesions on the spinal cord are often used to diagnose MS and the degree of disability, Sombekke’s team suggests that the association of HLA-DRB1*1501 with spinal cord lesions might help explain its relationship with severity of the disease.