Neurofibromatosis type 1 (NF1) is the most common and well-understood neurodermatologic disease, with an incidence of approximately 1/3000 to 1 in 4000 individuals. NF1 is an autosomal dominant disease caused by mutations in the NF1 gene located on chromosome 17q11.2. Approximately 50% of NF1 cases are familial, and the remaining cases occur sporadically.