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