Approximately 2 percent of Caucasians have a gene segment variation that can cause a certain form of schizophrenia. Most people with the variation, known as a polymorphism, do not have the disease. A University of Iowa Health Care study reveals a good prognosis for people who do have this form of schizophrenia. The team also found that this polymorphism is associated with overall benefits for human survival, and the initial mutation occurred in a single common ancestor about 100,000 years ago.
