A diagnosis of NF1 is made when an individual has two or more of the following findings:

  • At least six café-au-lait macules over 5 mm in greatest diameter before puberty, or six café-au-lait macules over 15 mm in greatest diameter after puberty
  • Two or more neurofibromas of any type or one plexiform neurofibroma
  • Multiple freckles in the axillary (armpit) or inguinal (groin) regions
  • A distinctive bone abnormality involving the eye socket or arm/leg bones
  • A tumor on the optic nerve located in the brain called an optic glioma
  • Two or more Lisch nodules on slit-lamp examination
  • A parent, sibling, or child with NF1