Clinical meaning
Neurofibromatosis type 1 (NF1, von Recklinghausen disease) is an autosomal dominant neurocutaneous disorder caused by mutations in the NF1 gene on chromosome 17, encoding neurofibromin, a tumor suppressor protein that inhibits the RAS-MAPK signaling pathway. Loss of neurofibromin function causes constitutive activation of RAS, promoting uncontrolled cell proliferation and tumor formation from Schwann cells and other neural crest derivatives. Diagnostic criteria (two or more of seven features) include six or more cafe-au-lait macules, two or more neurofibromas or one plexiform neurofibroma, axillary or inguinal freckling (Crowe sign), optic pathway glioma, two or more Lisch nodules (iris hamartomas), osseous dysplasia (sphenoid wing dysplasia, long bone bowing), and a first-degree relative with NF1. Neurofibromatosis type 2 (NF2) involves mutations in the merlin gene on chromosome 22, characterized by bilateral vestibular schwannomas causing progressive hearing loss. The nurse monitors for growth of existing neurofibromas and development of new lesions, assesses for signs of malignant peripheral nerve sheath tumor transformation (rapid growth, pain, new neurological deficit), monitors blood pressure (pheochromocytoma association), coordinates multidisciplinary care (neurology, ophthalmology, orthopedics, oncology), and provides genetic counseling support.