n. either of two hereditary conditions inherited as autosomal dominant traits and characterized by benign tumours growing from the fibrous coverings of nerves (see neurofibroma). In neurofibromatosis type I (von Recklinghausen’s disease), in which the abnormal gene is found on chromosome 17, numerous tumours affect the peripheral nerves. The tumours can be felt beneath the skin along the course of the nerves; they may become large, causing disfigurement, and rarely they become malignant, giving rise to neurofibrosarcomas. Pigmented patches on the skin (see café au lait spots) are commonly found and Lisch nodules are present. Neurofibromatosis type II presents with bilateral vestibular schwannomas (causing hearing loss) and meningiomas. The abnormal gene is on chromosome 22.
Subjects: Medicine and Health — Genetics and Genomics.