NIH Consensus Development Conference Criteria

Clinical CriteriaClinical Pearls
1. Six or more CALMs equal to or greater than 5 mm in longest diameter in prepubertal patients and 15 mm in longest diameter in postpubertal patients• 2–3 or fewer CALMs are normal in the population
• Typically, CALMs are present since infancy in people with NF1
• Typically have smooth edges
2. Two or more neurofibromas of any type or 1 plexiform neurofibroma• Dermal and subcutaneous neurofibromas not typically detectable until later in childhood
• Plexiform neurofibroma typically changes the color and/or texture of overlying skin
3. Freckling in the axillary or inguinal regions (Crowe sign)• Not typically detectable until age 5 or later
• Freckling in areas not exposed to the sun is unexpected in people without NF1
4. Optic glioma (OPG)• Not detectable without direct ophthalmoscopy
• May be present in infancy
• Early detection critical for preserving vision
5. Two or more iris hamartomas (Lisch nodules) (Fig 1)• Occurrence is age related (rarely present in infants and toddlers; present in about half of children by school age; present in most teenagers)
• Not detectable (without slit-lamp examination)
• Does not affect vision
6. A distinctive osseous lesion, such as sphenoid wing dysplasia or long-bone dysplasia (with associated cortical thickening and medullary canal narrowing), with or without pseudoarthrosis• Tibial dysplasia is the most common type of bone dysplasia
• Infants and toddlers with anterior-lateral tibial bowing on examination should have tibial radiographs and referral to orthopedics
7. A first-degree relative (parent, sibling, or child) with NF1 according to the aforementioned criteria• Parent who is affected should have some symptoms even if mildly affected (100% penetrance)
• NF1 does not skip a generation
  • Two or more criteria are required to establish the diagnosis of NF1. Adapted from Neurofibromatosis. Conference statement. National Institutes of Health Consensus Development Conference. Arch Neurol. 1988;45(5):575–578; National Institutes of Health Consensus Development Conference Statement: neurofibromatosis. Bethesda, Md., USA, July 13-15, 1987. Neurofibromatosis. 1988;1(3):172–178; and DeBella K, Szudek J, Friedman JM. Use of the national institutes of health criteria for diagnosis of neurofibromatosis 1 in children. Pediatrics. 2000;105(3, pt 1):608–614.