Rare Genetic Mutations Are Linked to Common Diseases

A recent New York Times article indicates that common human diseases such as cancer and psychiatric disorders are caused by a combination of rare genetic mutations. This is different from the "common disease, common variant" viewpoint that has guided previous research. It is easier to look for common genetic mutations than rare ones. This has proved to be a fruitless search. "Common variants have turned out to explain only a fraction of the genetic risk of common disease." The challenge for future research is that rare mutations are difficult to find, and require large sample sizes. Also, different races of people (e.g. Africans versus Europeans) will likely have different mutations. The bottom line is that we're a long way from understanding the genetic causes of psychiatric disorders such as depression, autism, or schizophrenia.