While a diagnosis of NF1 syndrome is typically made based on available clinical diagnostic criteria (below), molecular genetic testing of the NF1 gene may be appropriate to help confirm a suspected diagnosis under certain circumstances, such as when only one diagnostic feature is observed in a young child.1
A diagnosis of NF1 syndrome is made for individuals with 2 or more of the following features2:
- Six or more café au lait macules >5 mm in greatest diameter in prepubertal individuals, or >15 mm in greatest diameter in post-pubertal individuals
- Two or more neurofibromas of any type, or 1 plexiform neurofibroma
- Freckling in the axillary or inguinal regions
- Optic glioma
- Two or more Lisch nodules (iris hamartomas)
- A distinctive osseous lesion such as sphenoid dysplasia or tibial pseudarthrosis
- A first-degree relative (parent, sib, or offspring) with NF1 as defined by the above criteria
If molecular genetic testing is pursued, informed consent following genetic counseling is strongly recommended.