Adult patients with NF1 mutations not fulfilling the NIH criteria have been described and have distinct clinical features: (a) segmental forms of NF1, probably due to mosaic NF1 mutations; (b) spinal neurofibromatosis with extensive, symmetrical multiple tumors involving large regions of the spine and few, if any, cutaneous manifestations; (c) late‐onset neurofibromatosis as defined by Riccardi (1992) with only neurofibromas beginning in the 3rd decade; and (d) optic glioma with few cutaneous manifestations (Buske et al. The gene discussed is NF1; the disease is neurofibromatosis.