Darier Disease (DD) is a rare inherited disorder of cornification of the skin, nails and mucous membranes. Estimated prevalence of DD is 1/55,000 individuals and has been reported worldwide. Skin lesions begin with discrete, hard, hyperkeratotic papules mostly confined to chest and forehead. The lesions progressively develop into hyperkeratotic, macerated or crusted, malodorous plaques, which may cover most of the body and lead to secondary infection. DD is often associated with nail changes, in particular V-shaped notches and red and white longitudinal streaks. Skin lesions are exacerbated by trauma, including heat, sweat, friction and restrictive clothing. Peak of onset is between 11 and 20 years of age. The disease follows a chronic, progressive course, often leading to discomfort and disfigurement. In a few families, DD has been associated with neuropsychiatric abnormalities, such as major affective disorder, schizophrenia and epilepsy. DD is caused by mutations in the ATP2A2 gene located on chromosome 12q23-q24.1.