Atypical seems to refer to one of 2 things. Either you have established mutations but no clinical manifestations of CF. Or, you have clinical symptoms but no identifiable genetic mutations.
Its my understanding that most CFF accredited centers will NOT diagnose atypical CF without genetic mutations. But, its a definite grey area. Given that there are over 1000 identifed mutations the thinking that there are more which are not identified and perhaps someone with clinical symptoms would benefit from the same protocals and aggressive treatment as those with classic presentations of the disease. Whereas the other end of that coin is the thought that likely the patient actually has something else which is being missed by giving the diagnosis of atypical CF without the proven genetic mutation.
As for those with established mutations but not clinical symptoms, doctors really don't want to give the atypical diagnosis to children who are diagnosed because of symptoms. However, what happens is that often when a child is diagnosed, the doctors then trace the family tree back and start testing people. That's when you find the 30 year old uncle who's fit as a fiddle, never shown symptoms of disease...but his genetic screening says he has CF.
There's not an established agreement on what to do in those cases. Do you start the healthy adult on the aggressive protocal under the assumption that at SOME point they will progress. Or, do you watch them, study them and try to figure out why they have a known mutation but appear to not have a clinical presentation of the disease they should have.
So, some CF centers don't even deal with the diagnosis of atypical. Others do. But, the term is definite something different than the mild/moderate/severe classification.
