Cause of neurofibromatosis

The three types of Neurofibromatosis are caused by different mutations on chromosomes. NF1 is caused by a mutation on the NF1 gene on the arm of chromosome 17.¹² NF2 is caused by a mutation on the NF2 tumor suppressor gene on chromosome 22.¹² Schwannomatosis is caused by various mutations on chromosome 22.¹²

Neurofibromatosis is an autosomal dominant disorder, which means only one copy of the affected gene is needed for the disorder to develop.¹³ If one parent has neurofibromatosis, his or her children have a 50% chance of developing the condition as well. The severity of the parent's condition does not affect the child; the affected child may have mild NF1 even though it was inherited from a parent with a severe form of the disorder.¹⁴ The types of neurofibromatosis are:

• Neurofibromatosis type I, in which the nerve tissue grows tumors (neurofibromas) that may be benign, but may cause serious damage by compressing nerves and other tissues.¹⁵
• Neurofibromatosis type II, in which bilateral acoustic neuromas (tumors of the vestibulocochlear nerve or cranial nerve 8 (CN VIII) also known as schwannoma) develop, often leading to hearing loss.¹⁶
• Schwannomatosis, in which painful schwannomas develop on spinal and peripheral nerves.¹⁷