NF1 and nervous system neoplasm: NF1 is the most typical neurofibromatosis, accounting for about 90% of all cases and occurs in about 1/3,000, and characterized by multiple café au lait macules (CALMs), skinfold freckling (also known as the lentiginous macules), iris Lisch nodules, tumors of the nervous system, and other features caused by mutations in the NF1 gene on chromosome 17 (Legius et al., 2021).