A multistep approach to the diagnosis of rare genodermatoses.

Recent advances in genetic technology have found their way into clinical dermatology. Approximately one third of all hereditary disorders show characteristic cutaneous findings. Moreover, human skin easily provides samples for studying the mechanisms of genetic mosaicism, as well as the underlying functional defects due to mutated proteins. Diagnosing hereditary skin disorders remains, however, a challenging task due to the rarity of genodermatoses and their diversity, overlapping or heterogeneous phenotypes, huge amount of new information, and complicated nomenclature and classifications. In order to support the clinicians' interest for this complex and rapidly developing field of dermatology, we are going to present a multistep approach with some useful clues for the evaluation of patients suspected of having a genodermatosis.