For example, the treatments for Reiters have only limited effectiveness, there is no cure. If you have a disease that is similar to Reiters and it does have an effective treatment or cure, you may suffer needlessly. A rheumatologist is usually required to diagnose Reiters. There is no medical test that proves Reiters. There is a gene marker, but it only indicates a predisposition for Reiters.
Nobody knows if the gene is part of the cause.
Also it is possible not to have the gene marker, but to have Reiters. For example, the treatments for Reiters have only limited effectiveness, there is no cure. If you have a disease that is similar to Reiters and it does have an effective treatment or cure, you may suffer needlessly. A rheumatologist is usually required to diagnose Reiters. There is no medical test that proves Reiters.