Its diagnosis is based on the presence of at least two criteria, including six or more café-au-lait macules (CALMs), axillary or inguinal freckling, two or more neurofibromas or one plexiform neurofibroma (pNF), an optic pathway glioma, Lisch nodules or choroidal abnormalities, distinctive bone lesions, or a pathogenic variant in the NF1 gene. This evidence concerns the gene NF1 and plexiform neurofibroma.