Neurofibromatosis is a group of three situations wherein tumours grow within the nervous system. The three types are neurofibromatosis type 1, neurofibromatosis kind 2, and schwannomatosis. In Type 1 signs and symptoms include light brown spots on the skin, freckles within the armpit and groin, small bumps within nerves, and scoliosis. In Type 2 there can be hearing loss, cataracts at a young age, balance problems, flesh coloured skin flaps, and muscle wasting. The tumours are generally non-cancerous. The reason is a genetic mutation in sure genes. In half of cases these are inherited from a person's mother and father while in the rest, they arise in the course of early development.