When newspapers announce that a gene has been discovered for a certain disease — such as the recent findings of genes involved in chronic fatigue syndrome, schizophrenia, and obesity — we inevitably get calls from people interested in testing for that genetic finding. But “finding a gene” can mean a few different things. Finding the gene: Sometimes, researchers identify a gene that definitely causes a disease, such as the discovery of the gene for hemophilia or cystic fibrosis. Such a finding does not necessarily mean that a genetic test is immediately available or that researchers can cure the disease. However, it does mean that the medical community may be closer to a possible cure. Knowing the genetic origin of a disease can aid in diagnosis.
Finding one of many genes: In other cases, researchers discover a gene that plays a role in a small subset of people who get a common disease, such as the genes BRCA1 and BRCA2, which cause breast and ovarian cancer in some people. Again, finding these genes puts researchers one step closer to a cure or genetic test that can help certain people with the disease.
Finding a gene in animals: One way to understand gene function in humans is to find and manipulate a gene that causes an animal — such as the mouse or fruit fly — to show symptoms similar to a human disease. Animals have genes that are very similar to our own, so these discoveries help point researchers to the biological function of a human disease gene. However, it is a long path from finding a gene in flies or mice to finding a genetic treatment for a human disease.