[Important genodermatoses for the practitioner].

Health or disease is a result of the genetic constellation and environmental influences. The phenotype of monogenic diseases is highly influenced by one single mutation. According to the WHO more than 10,000 monogenic diseases exist while for 1,000 diseases a molecular genetic test is available. Genodermatoses are well-documented and characterized; the most important data base for the diagnosis is the Online Mendelian Inheritance of Men data base, which can be searched in Google with the keyword "OMIM". Here genetic diseases are categorized and clinically described. We present our own epidemiologic data from the Department of Dermatology, University Hospital Basel, concerning genodermatoses. Our results show that the most common genodermatoses seen in the daily practice are porokeratoses, ichthyoses, Darier disease, neurofibromatosis and epidermolysis bullosa. They account for 91% of all genodermatoses seen in a hospital-based dermatology department of Dermatology.