Neurofibromatosis is a genetic disorder that causes tumors to form on nerve tissue. These tumors can develop anywhere in the nervous system, including the brain, spinal cord, and nerves. The condition is classified into two main types: Neurofibromatosis Type 1 (NF1) and Neurofibromatosis Type 2 (NF2). There is also a much rarer type known as Schwannomatosis.