What causes rare diseases?
For many rare diseases, the exact cause remains unknown. Still, for a significant portion, the problem can be traced to changes, or mutations, in a single gene. Such diseases are referred to as rare, genetic diseases. Many of these genetic mutations can be passed on from one generation to the next, explaining why certain rare diseases run in families. Keep in mind that genetics are just one piece of the puzzle. Environmental factors, such as diet, smoking or exposure to chemicals, also can play a role in rare diseases. Such factors may directly cause disease, or interact with genetic factors to cause or increase the severity of disease.
