Hello @apineda, a very complex and rare disease as you well put it, I think there must be few cases, during my professional practice I never saw any case, however, I know of the existence of it. The symptoms are multiple, besides that they could be associated with some other pathology.
It will always be important that subspecialties exist, because they are the most qualified to make certain diagnoses and apply new treatments. Greetings, very good explanation.