The cause is a genetic mutation in certain genes. In half of cases these are inherited from a person's parents while in the rest, they occur during early development. The tumors involve supporting cells in the nervous system rather than the neurons. In NF1 the tumors are neurofibromas (tumors of the peripheral nerves), while in NF2 and schwannomatosis tumors of Schwann cells are more common. Diagnosis is typically based on the signs and symptoms and occasionally supported by genetic testing.
There is no known prevention or cure. Surgery may be done to remove tumors that are causing problems or have become cancerous. Radiation and chemotherapy may also be used if cancer occurs. A cochlear implant or auditory brainstem implant may help some who have hearing loss.
In the United States, about 1 in 3,500 people have NF1 and 1 in 25,000 have NF2. Males and females are affected equally frequently. In NF1, symptoms are often present at birth and otherwise develop before 10 years of age. While the condition typically worsens with time, most people with NF1 have a normal life expectancy. In NF2, symptoms may not become apparent until early adulthood. NF2 increases the risk of early death. Descriptions of the condition occur as far back as the 1st century.
Signs and Symptoms
Neurofibromatosis (NF1) in early life may cause learning and behavior problems – about 60% of children who have NF1 have a mild form of difficulty in school. In terms of signs the individual might have are the following:
- Six or more light brown dermatological spots ("cafΓ© au lait spots")
- At least two neurofibromas
- At least two growths on the eye's iris
- Abnormal growth of the spine (scoliosis)
π️Cause
Neurofibromatosis is an autosomal dominant disorder, which means only one copy of the affected gene is needed for the disorder to develop. If one parent has neurofibromatosis, his or her children have a 50% chance of developing the condition as well. The severity of the condition of the parent does not affect the child; the affected child may have mild NF1 even though inherited from a parent with a severe form of the disorder. The types of neurofibromatosis are:
- Neurofibromatosis type I, in which the nerve tissue grows tumors (neurofibromas) that may be benign, may cause serious damage by compressing nerves and other tissues.
- Neurofibromatosis type II, in which bilateral acoustic neuromas (tumors of the vestibulocochlear nerve or cranial nerve 8 (CN VIII) also known as schwannoma) develop, often leading to hearing loss.
- Schwannomatosis, in which painful schwannomas develop on spinal and peripheral nerves.
π️Treatment
Surgical removal of tumors is an option, however the risks involved should be assessed first. With regard to OPG (optic pathway gliomas), the preferred treatment is chemotherapy. However, radiotherapy isn't recommended in children who present with this disorder. It is recommended that children diagnosed with NF1 at an early age have an examination each year, which allows any potential growths or changes related to the disorder to be monitored.
π️Prognosis
In most cases, symptoms of NF1 are mild, and individuals live normal and productive lives. In some cases, however, NF1 can be severely debilitating and may cause cosmetic and psychological issues. The course of NF2 varies greatly among individuals. In some cases of NF2, the damage to nearby vital structures, such as other cranial nerves and the brain stem, can be life-threatening. Most individuals with schwannomatosis have significant pain. In some extreme cases the pain will be severe and disabling.
π️The tumors may be harmless, or they may compress the nerves and other tissues, leading to serious damage.
Neurofibromatosis (Nf) is the most common genetic neurological disorder that is caused by a single gene. The mutation in the gene means that the nerve tissue is not properly controlled.
Neurofibromas are not generally painful, but if their location on the body means that they graze or catch on clothing, they can be removed. This reduces the risk of itching, infection, numbness, and general discomfort. However, they may grow back.
If tumors growing on the optic nerve are affecting eyesight, they can be surgically removed.
Scoliosis, or curvature of the spine, can be corrected through surgery or by wearing a back brace.
Normally, the tumors are regularly monitored, and treatment is given as required.
Surgery for acoustic neuromas does not always improve hearing and may worsen it. The decision to remove an acoustic neuroma will depend on the size of the tumor and how rapidly it is growing, not only on hearing loss.
Sometimes a surgeon will insert an auditory brain stem implant (ABI) to help a person's hearing. They may remove a vestibulocochlear nerve tumor at the same time.
π️Scientists have classified the disorders as neurofibromatosis type 1 (NF1, also called von Recklinghaus disease), neurofibromatosis type 2 (NF2), and a type that was once considered to be a variation of NF2 but is now called schwannomatosis. An estimated 100,000 Americans have a neurofibromatosis disorder, which occurs in both sexes and in all races and ethnic groups.
The most common nerve-associated tumors in NF1 are neurofibromas (tumors of the peripheral nerves), whereas schwannomas (tumors that begin in Schwann cells that help form the myelin sheath) are most common in NF2 and schwannomatosis. Most tumors are benign, although occasionally they may become cancerous.
Why these tumors occur still isn’t completely known, but it appears to be related mainly to mutations in genes that play key roles in suppressing cell growth in the nervous system. These mutations keep the genes—identified as NF1, NF2 and SMARCB1/INI1—from making normal proteins that control cell production. Without the normal function of these proteins, cells multiply out of control and form tumors.
What are the signs and symptoms of NF1?
To diagnose NF1, a doctor looks for two or more of the following:
- six or more light brown spots on the skin (often called “cafΓ©-au-lait” spots), measuring more than 5 millimeters in diameter in children or more than 15 millimeters across in adolescents and adults;
- two or more neurofibromas, or one plexiform neurofibroma (a neurofibroma that involves many nerves);
- freckling in the area of the armpit or the groin;
- two or more growths on the iris of the eye (known as Lisch nodules or iris hamartomas);
- a tumor on the optic nerve (called an optic nerve glioma)
- abnormal development of the spine (scoliosis), the temple (sphenoid) bone of the skull, or the tibia (one of the long bones of the shin);
- a parent, sibling, or child with NF1.
What other symptoms or conditions are associated with NF1?
Many children with NF1 have larger than normal head circumference and are shorter than average. Hydrocephalus, the abnormal buildup of fluid in the brain, is a possible complication of the disorder. Headache and epilepsy are also more likely in individuals with NF1 than in the healthy population. Cardiovascular complications associated with NF1 include congenital heart defects, high blood pressure (hypertension), and constricted, blocked, or damaged blood vessels (vasculopathy). Children with NF1 may have poor language and visual-spatial skills, and perform less well on academic achievement tests, including those that measure reading, spelling, and math skills. Learning disabilities, such as attention deficit hyperactivity disorder (ADHD), are common in children with NF1. An estimated 3 to 5 percent of tumors may become cancerous, requiring aggressive treatment. These tumors are called malignant peripheral nerve sheath tumors.
When do symptoms appear?
Symptoms, particularly the most common skin abnormalities-cafΓ©-au-lait spots, neurofibromas, Lisch nodules, and freckling in the armpit and groin-are often evident at birth or shortly afterwards, and almost always by the time a child is 10 years old. Because many features of these disorders are age dependent, a definitive diagnosis may take several years.
What is the prognosis for someone with NF1?
NF1 is a progressive disorder, which means most symptoms will worsen over time, although a small number of people may have symptoms that remain constant. It isn’t possible to predict the course of an individual’s disorder. In general, most people with NF1 will develop mild to moderate symptoms. Most people with NF1 have a normal life expectancy. Neurofibromas on or under the skin can increase with age and cause cosmetic and psychological issues.
How is NF1 treated?
Scientists don’t know how to prevent neurofibromas from growing. Surgery is often recommended to remove tumors that become symptomatic and may become cancerous, as well as for tumors that cause significant cosmetic disfigurement. Several surgical options exist, but there is no general agreement among doctors about when surgery should be performed or which surgical option is best. Individuals considering surgery should carefully weigh the risks and benefits of all their options to determine which treatment is right for them. Treatment for neurofibromas that become malignant may include surgery, radiation, or chemotherapy. Surgery, radiation and/or chemotherapy may also be used to control or reduce the size of optic nerve gliomas when vision is threatened. Some bone malformations, such as scoliosis, can be corrected surgically.
Treatments for other conditions associated with NF1 are aimed at controlling or relieving symptoms. Headache and seizures are treated with medications. Since children with NF1 have a higher than average risk for learning disabilities, they should undergo a detailed neurological exam before they enter school. Once these children are in school, teachers or parents who suspect there is evidence of one or more learning disabilities should request an evaluation that includes an IQ test and the standard range of tests to evaluate verbal and spatial skills.
What is NF2?
This rare disorder affects about 1 in 25,000 people. Approximately 50 percent of affected people inherit the disorder; in others the disorder is caused by a spontaneous genetic mutation of unknown cause. The hallmark finding in NF2 is the presence of slow-growing tumors on the eighth cranial nerves. These nerves have two branches: the acoustic branch helps people hear by transmitting sound sensations to the brain; and the vestibular branch helps people maintain their balance. The characteristic tumors of NF2 are called vestibular schwannomas because of their location and the types of cells involved. As these tumors grow, they may press against and damage nearby structures such as other cranial nerves and the brain stem, the latter which can cause serious disability. Schwannomas in NF2 may occur along any nerve in the body, including the spinal nerves, other cranial nerves, and peripheral nerves in the body. These tumors may be seen as bumps under the skin (when the nerves involved are just under the skin surface) or can also be seen on the skin surface as small (less than 1 inch), dark, rough areas of hairy skin. In children, tumors may be smoother, less pigmented, and less hairy.
Although individuals with NF2 may have schwannomas that resemble small, flesh-colored skin flaps, they rarely have the cafΓ©-au-lait spots that are seen in NF1.
Individuals with NF2 are at risk for developing other types of nervous system tumors, such as ependymomas and gliomas (two tumor types that grow in the spinal cord) and meningiomas (tumors that grow along the protective layers surrounding the brain and spinal cord). Affected individuals may develop cataracts at an earlier age or changes in the retina that may affect vision. Individuals with NF2 may also develop problems with nerve function independent of tumors, usually symmetric numbness and weakness in the extremities, due to the development of a peripheral neuropathy.
Where can I get more information?
Blogger: Egypt A. Assanti
ESD Baroness
{aka}Big Sister Southern Heat π️
