The most common form of neurofibromatosis (NF) is NF-1. It is sometimes referred to as peripheral neurofibromatosis or von Recklinghausen’s disease. People with NF-1 generally have brown oval or circular spots on the skin called café-au-lait spots and freckles under the arm or in the groin area. Benign soft tumors or lumps in or under the skin called neurofibroma and brownish red spots in the iris--the colored part of the eye--called Lisch nodules, are present in most people.
NF-1 frequently causes learning difficulties in children. It may affect physical growth. In addition, tumors may form along nerves anywhere in the body.
Some signs of NF-1 are usually visible within the first year of life. Other signs of NF-1 may develop, as people get older. For example, Lisch nodules of the iris are unusual in young children but commonly develop in teenagers and adults. Neurofibromas frequently appear or grow during the hormonal changes that occur in teenage years and during pregnancy. It is important to remember that while the problems caused by NF-1 can be serious, NF-1 usually does not keep people who have it from living a normal and productive life.
Some people with NF-1 will only have café-au-lait spots and neurofibroma, but others may have more difficult problems. At the present time, it is impossible to predict what kinds of problems an individual will have. No two people will be affected in exactly the same way, even within the same family.