How do you decide when to obtain genetic testing for suspected autoinflammatory conditions in adults?

We have identified an autoinflammatory disorder that occurs in people of the Southern Appalachian mountains known as "Melungeons." Several have been evaluated at NIH, and while they do not have any of the known markers the diagnosis of familial Mediterranean fever has been confirmed. Dr. Kastner told me that while the presence of the markers can help support the diagnosis, there are many cases (up to 1/3) that do not have the markers. In essence, the absence of the markers does NOT exclude the diagnosis; they probably have genetic markers that have not yet been identified. The FMF criteria include "favorable response to colchicine;" a trial of this agent in someone thought to have FMF is often easier, and less costly than doing the testing.