MS Risk Among Relatives Lower Than Expected

Although MS is usually an inherited illness, relatives of patients with the disease may be at a lower risk for developing it than is generally expected, the results of a Swedish study suggest.

Researchers at Sweden’s Karolinska Institute used the Swedish Multiple Sclerosis Registry and a nationwide hospital registry to identify 28,396 patients diagnosed with MS since 1968. Using the Multi-Generation Registry and the Swedish Twin Registry, first- and second-degree relatives and cousins of MS patients were identified and their risk for developing the disease was calculated. These results were then compared with the calculated risks of relatives of a group of individuals without MS. The findings were published online on January 17, 2014, in Brain.

Siblings of MS patients were 7 times more likely to develop MS, while children of MS patients were 5 times more likely to inherit the disease compared with those without a family history of the disease. However, grandchildren and nieces and nephews of MS patients did not have an increased risk for developing the disease compared with the general population.

“[O]ur findings suggest a theoretically smaller number of multiple sclerosis risk genes, indicating that a greater proportion of the genes contributing to multiple sclerosis susceptibility have been identified than previously thought,” the authors of the study conclude.