How can you tell if someone has neurofibromatosis?

What type? Nf-1 has classic skin manifestations - one just examines skin to see if criteria for the number/size of nevi and ash-leaf spots on the skin are seen.
Many manifestations. Several signs of nf1, main one 6 or mor flat brown spots over 5 mm in greatest diameter in children and over 15 mm in greatest diameter in post-pubertal individuals, two or more soft nodules or neurofibromas or 1 plexiform neurofibroma, freckling in the axillary or groin regions, tumors of optic nerve, gliomas, bony abnormality such as scoliosis, bone overgrowth or congenital fracture.
Multiple lumps. The neurofibromas tend to be everywhere and visible, large brown spots are common"cafe au lait" spots. Some patients will also have pheochromocytoma there is a family tendency.