Neurofibromatosis is an inherited chronic neurocutaneous condition that involves the nervous system and the skin. There are two distinct forms of neurofibromatosis, NF-1, Von Recklinghausen’s Disease or peripheral neurofibromatosis and the rare form NF-2 or central neurofibromatosis. The more common NF-1 is characterized by changes in the pigmentation of the skin, tumors within the central and peripheral nervous systems and lesions of the vascular system and other organs. NF-1 has an incidence of approximately one in four thousand adolescents. NF-2 is characterized by tumors of both acoustic nerves-which direct auditory information from the inner ears to the hearing centers in the brain. The incidence of NF-2 is approximately one in fifty thousand adolescents.
Approximately fifty percent of adolescents with neurofibromatosis have affected relatives. The distribution of cases is such that the inheritance of this disorder is through an autosomal dominant mechanism. For example, the children of a patient with neurofibromatosis have a fifty percent chance of acquiring the disease genetically, and this is regardless of the gender of the offspring. About fifty percent of adolescents with NF-1 have a spontaneous mutation of the NF-1 gene that is located on chromosome 17q. This mutation occurs around the time of their conception. The gene for NF-2 is located on chromosome 22.
Regardless of whether the adolescent inherits the neurofibromatosis gene from a parent or if there is a spontaneous mutation around the time of conception that produces the gene, neurofibromatosis is a congenital and chronic disease. The teen is born with the genetic makeup to produce the symptoms of the disease, and these symptoms will usually present during the latter part of the first decade and during adolescence.
Who is likely to develop neurofibromatosis?
Adolescents have a fifty percent chance of developing neurofibromatosis if a parent is diagnosed with the disease. If both of the adolescent’s parents have neurofibromatosis, then virtually one hundred percent should acquire the disease. There is no way to predict those embryos that will develop the spontaneous gene mutation that leads to neurofibromatosis.
What are the symptoms of neurofibromatosis?
Neurofibromatosis (NF-1) is characterized in adolescents by the presence of six or more light brown skin spots larger than ½ inch each; these are called café au lait spots. These are usually painless. Patients often have two or more rubbery bumps under the skin that are called neurofibromas. Also, there may be freckling in the armpits or groin and growths on the iris of the eyes that are called Lisch nodules. A family history of NF-1 may also be present. Neurofibromas may cause pain, become infected, damage organs or produce cosmetic concerns in adolescents. Other teens with NF-1 may enter puberty earlier or later than expected, and some also may develop scoliosis, a curvature of the spine. Teens with scoliosis may complain of back pain. And high blood pressure, which could have no symptoms or headache as a symptom, may occur albeit rarely in NF-1.
The symptoms of NF-2 usually occur during or after adolescence. Since a mass on both acoustic nerves is seen in NF-2, symptoms may include ringing in the ear, buzzing or background noise in the head. Some patients have a loss of hearing. However, one may also see café au lait spots and feel the neurofibromas.
In both variants of neurofibromatosis, there may be mental retardation, speech problems, seizures, learning disabilities and hyperactivity. Some patients also may have a big head or short stature. School function issues as a symptom may occur during primary school; speech articulation problems may become obvious during adolescence.
How is neurofibromatosis evaluated?
The most important first step in the evaluation is a thorough medical history and physical examination. Careful ophthalmic assessment for Lisch nodules is important as well as a thorough neurological examination. Neuroimaging may be valuable to demonstrate masses that would be consistent with neurofibromas or other areas of unusual tissue collection. For NF-2, an audiogram is necessary to provide a baseline of the adolescent’s hearing. Neuroimaging studies may be ordered to demonstrate presence of acoustic neuromas. Other specialties may be involved including dermatology, otolaryngology and endocrinology.
How is neurofibromatosis treated?
The treatment of neurofibromatosis is supportive and symptomatic. For example, if the neurofibromas are disfiguring, painful, subject to repeated injury or show rapid growth, they may be surgically removed. Neurofibromas that are in the brain or spine may be treated, if necessary, with surgery, radiation or chemotherapy. Seizures may be treated with antiseizure medications. Scoliosis may be treated with exercises, bracing or surgery depending on the severity of the condition.
The clinical condition of patients with NF-2 may be quite benign so surgery may not be necessary to remove the neuromas from the auditory nerves. These neuromas do not necessarily lead to deafness or facial disfigurement.
Adolescents with NF-1 are at higher risk for social and emotional problems. As a result, parents should be carefully advised that their child with NF-1 may have school related issues, and many advise including the teachers in information about neurofibromatosis. Counseling should be made available to parents and the adolescent with neurofibromatosis. Adolescents may develop concerns in regard to short stature, early or late puberty or even sexual identity. Acting out behaviors could occur. Adolescents may also have issues in regard to their attractiveness to other teens and their future potential to have a family. Some adolescents with neurofibromatosis may become depressed or even suicidal. Each of these issues may require counseling interventions.
The genetic basis for neurofibromatosis should be explained to teens with the disease. While a consultation with a geneticist is not usually necessary during adolescence, it certainly may be warranted around the time of marriage or initiation of a family.
How is neurofibromatosis prevented?
Neurofibromatosis cannot be prevented since the adolescent acquires the disease at the time of conception. For prospective parents, one of whom has neurofibromatosis or if there is a family history for the disease, genetic counseling is mandatory. There is an active research program to discover medications to help allay the symptoms of neurofibromatosis.
Further information about neurofibromatosis may be obtained from the National Neurofibromatosis Foundation at 800-323-7938 or access their website at http://nf.org.
Related topics:
Attention deficit disorder, birthmarks, brain disorders, chronic illness, depression, growth and development, hearing loss, learning disorders
