Neurofibromatosis is a genetic disorder of the nervous system, and it causes tumors to grow on the ends of nerve tissue. These tumors can appear anywhere in the body, including along the spinalcord, in the brain and on nerves. Neurofibromatosis is genetic, and is caused by a mutation of the NF-1or NF-2 gene. Parents who have NF have a 50% chance of passing NF along to their children. However,although NF is genetic, it is estimated that 50% of NF cases are not genetic, and instead are due to a spontaneous mutation of a gene.