The clinical spectrum of neurofibromatosis type 1 (NF1) is broad and dependent on in which cell type the biallelic inactivation of the NF1 (Neurofibromin 1) gene takes place, such as melanocytes (café-au-lait macules [CALM]), osteoblasts (tibial dysplasia), and Schwann cells (cutaneous neurofibroma [cNF] and plexiform neurofibroma [pNF]). This evidence concerns the gene NF1 and neurofibromatosis type 1.