Neurofibromatosis

The presenting features of neurofibromatosis type 1 (NF1,
peripheral neurofibromatosis, von Recklinghausen disease) and
neurofibromatosis type 2 (NF2, central neurofibromatosis) are
described in chapter 10. Benign optic gliomas and spinal
neurofibromas may occur in NF1 and malignant tumours,
mainly neurofibrosarcomas or embryonal tumours, occur in 5%
of affected people. The gene for NF1 on chromosome 17 has
been cloned, but mutation analysis is not routinely undertaken
because of the large size of the gene (60 exons) and the
diversity of mutations occurring. Deletions of the entire gene
have been found in more severely affected cases.