Which item is not among the National Institutes of Health diagnostic criteria for NF1?

Which item is not among the National Institutes of Health diagnostic criteria for NF1?

• A. Family hx of first degree relative with NF1
• B. 6 or more “café au lait” spots >15 mm
• C. freckling in armpits or groin
• D. optic glioma

Answer: (B)

NF1 is diagnosed when a person meets two or more NIH criteria, which include a first-degree relative with NF1, axillary or inguinal freckling, optic glioma, two or more Lisch nodules, two or more neurofibromas (or one plexiform neurofibroma), distinctive osseous lesions, and six or more café-au-lait macules. The café-au-lait criterion is not simply “six spots bigger than 15 mm”; the size threshold depends on age: in prepubertal children the macules should be larger than 5 mm, and in postpubertal individuals larger than 15 mm. The item stating six café-au-lait spots greater than 15 mm does not correctly specify the age-dependent size criterion, so it does not accurately reflect NIH diagnostic criteria. The other items listed—family history with NF1, axillary/inguinal freckling, and optic glioma—are all valid NIH criteria.

NF1 is diagnosed when a person meets two or more NIH criteria, which include a first-degree relative with NF1, axillary or inguinal freckling, optic glioma, two or more Lisch nodules, two or more neurofibromas (or one plexiform neurofibroma), distinctive osseous lesions, and six or more café-au-lait macules. The café-au-lait criterion is not simply “six spots bigger than 15 mm”; the size threshold depends on age: in prepubertal children the macules should be larger than 5 mm, and in postpubertal individuals larger than 15 mm. The item stating six café-au-lait spots greater than 15 mm does not correctly specify the age-dependent size criterion, so it does not accurately reflect NIH diagnostic criteria. The other items listed—family history with NF1, axillary/inguinal freckling, and optic glioma—are all valid NIH criteria.