Study Uncovers Genetic Origins of Multiple Sclerosis

While the true cause of Multiple Sclerosis (MS) remains unknown, insights into its origins are starting to emerge, according to the findings of a Cambridge-led study. This study revealed that the genetic risk associated with MS first appeared among pastoralists from the Pontic steppe. This discovery marks a substantial advancement in the scientific understanding of the evolution of MS, according to William Barrie, first author of the study.

“These results change our view of the causes of multiple sclerosis and have implications for the way it is treated,” said Eske Willerslev, Project Director, University of Cambridge. Currently, there is no cure for MS, but tailored treatments can manage the condition and alleviate symptoms based on the disease stage and specific manifestations.

MS is an autoimmune condition in which the body's immune system mistakenly attacks the protective layer around nerve fibers, known as myelin, effectively disrupting communication between the brain and the rest of the body, according to Mayo Clinic. This breakdown in communication occurs because the nerves can no longer transmit signals to and from the brain, as reported by John Hopkins Medicine. Despite these understandings, the exact cause of MS remains uncertain; however, it is presently believed to arise from an interplay of genetic, environmental, and lifestyle factors.

Building on our evolving understanding, the study has uncovered that Yamnaya nomads from the Pontic Steppe were found to harbor genetic mutations providing potential protection against pathogens transmitted by their animals. However, while these mutations might have been advantageous at the time, they simultaneously heightened the sensitivity of their immune systems, predisposing the nomad’s descendants to an exaggerated immune response. These findings were derived from the analysis of the remains of nearly 5,000 human beings who inhabited Western Europe and Asia up to 34,000 years ago, enabling a team of researchers to establish the world's largest ancient human gene bank. This discovery holds promise for the development of more precise treatments, as it sheds light on the intricate interplay between genetics, immunity, and the historical context.

“Showing how the lifestyles of our ancestors impacted modern disease risk [] highlights how much we are the recipients of ancient immune systems in a modern world,”  Barrie told the University of Cambridge.

According to the WHO, approximately 1.8 million people worldwide are believed to be affected by MS. However, the prevalence of multiple sclerosis is notably higher in Northern Europe, North America, Australia, and New Zealand, as reported by Multiple Sclerosis Trust. Meanwhile, in Mexico, “where there is a significant degree of blending, the prevalence of multiple sclerosis is higher than in other Latin American countries," said Irene Treviño, Faculty of Medicine Academic, National Autonomous University of Mexico (UNAM). As of 2022, around 20,000 individuals were estimated to be living with this condition.