Dermatology, the specialized study of skin diseases, is an important subdivision of the practice of medicine not only because of the various primary diseases affecting the skin, but also because of the common cutaneous manifestations of deeper visceral or systemic diseases. There are several dermatologic disorders that have a genetic aetiology or a genetic predisposition. Such genetically determined skin disorders are termed as ¿Genodermatoses¿. There exist many genodermatoses which have distinct oral features that may help identify or confirm a genetic diagnosis. In this book we have accrued various genetic diseases with oral manifestations and is a concise manual with vivid illustrations and our very own proposed classification which is both comprehensible and applicable in the clinical practice. Therefore it is of utmost importance to a dentist to recognize that, not only some dermatoses exhibit concomitant lesions of the oral mucous membranes but also that manifestations of some diseases, may be preceded by oral lesions which may otherwise go unnoticed.