Summary: An international team of researchers analyzed ancient genetic material (DNA) from skeletal remains of humans who lived across Europe over thousands of years ago to determine if there are ancestral links to genes that increase MS risk. They found that genetic changes associated with MS were first introduced to northern Europe about 5,000 years ago by migrating animal herders. These genetic changes were related to immune system function and may have provided protection against infections or pathogens, but over time they started to contribute to the autoimmune response seen in MS. More work is needed to understand the causes and triggers of MS in all individuals living with the disease.
Background: MS occurs in most ethnic groups including Black, Asian and Hispanic people, but risk of susceptibility to MS can vary among these groups. Genetic factors account for up to 30% of the total risk for MS, while environmental and lifestyle factors like Epstein-Barr virus infection, smoking and obesity are believed to be the major disease contributors.
Details: The goal of the study was to determine the ancestral origins of genes that increase the risk for MS. The researchers analyzed ancient genetic material (DNA) from more than 300 skeletons found in Europe that were between 1,200 to 25,000 years old. They combined this information with previous studies that collected ancient genetic material from more than 1,600 skeletons across Eurasia and compared it to modern-day genetic samples from the UK Biobank and 1000 Genomes project.
Results: The study found that many of the genetic changes associated with increased risk of MS first appeared in a population of animal herders from the Pontic Steppe region (spanning parts of central and eastern Europe). This herding population migrated to northwestern Europe about 5,000 years ago and most likely brought genes that today are known to increase people’s risk of MS. The study showed that these genetic changes were related to immune system function and may have provided a survival advantage by fighting off infections or pathogens from their sheep or cattle. However, over time the same genetic changes started contributing to the overly active immune response seen in MS.
Impact: These results demonstrate how exposure to specific environmental conditions have led to a genetic adaptation that have profound effects on the health of modern-day people by increasing their risk to diseases such as MS. Understanding the cause and triggers of MS will help develop strategies for preventing disease development. While this study focused on people with European ancestry, it is important to note that MS affects people of different ethnic groups, and more work is needed to understand MS in other populations.
Reference:
Article published in: Nature on January 10, 2024 – Elevated genetic risk for multiple sclerosis emerged in steppe pastoralist populations. Link to article – here.