Fact 7: Genetic and Environmental Factors Matter
Multiple sclerosis isn’t traditionally considered a genetic disease like cystic fibrosis or Huntington’s disease, where a single faulty gene is passed down through generations. However, research suggests there’s a clear genetic component involved. If you have a close relative, such as a sibling or parent, with MS, your risk of developing the disease is substantially higher than that of the general population.
Alongside genetics, environmental factors also play a crucial role in the onset and progression of MS. Several such factors have been identified, including low levels of vitamin D and exposure to cigarette smoke. These environmental triggers don’t cause MS on their own, but they can significantly increase the risk in individuals who are genetically predisposed.
Geography, too, plays a part. The prevalence of MS is highest in countries farthest from the equator. This geographic pattern suggests that sunlight exposure – or the lack thereof – may be a key environmental factor in MS development. People living in these regions often have lower levels of vitamin D, which is produced in the skin in response to sunlight.
Genetic and environmental factors don’t exist in silos; they interact with each other in ways that we’re just starting to understand. For instance, an individual may carry certain genetic traits that increase their susceptibility to environmental triggers. These complex interactions make MS a quintessential example of a multifactorial disease, where multiple genes and environmental factors combine to cause the condition. (7)
