Neurofibromatose
Neurofibromatose, also known as neurofibromatosis, designates a group of autosomal‑dominant genetic disorders characterized by the development of multiple benign nerve‑sheath tumors (neurofibromas) and a range of cutaneous, ocular, skeletal and neurologic manifestations. Three distinct clinical forms are recognized. Neurofibromatosis type 1 (NF1) results from mutations in the NF1 gene on chromosome 17 and is the most common, affecting roughly 1 in 3 000 individuals. Typical features include café‑au‑lait macules, axillary or inguinal freckling, Lisch iris hamartomas, and a predisposition to malignant peripheral nerve‑sheath tumors. Neurofibromatosis type 2 (NF2) is caused by mutations in the NF2 gene on chromosome 22 and is less frequent (about 1 in 25 000). Its hallmark is bilateral vestibular schwannomas, often leading to hearing loss, together with other cranial and spinal schwannomas. A third entity, schwannomatosis, involves multiple non‑vestibular schwannomas without the diagnostic criteria of NF1 or NF2 and is linked to mutations in the SMARCB1 or LZTR1 genes.
Diagnosis relies on clinical criteria supported by genetic testing. Imaging, particularly MRI, helps assess tumor burden