Neurofibromatosis is a genetic disease of the nervous system that causes tumors to form throughout the body. It is progressive and is one of the most common genetic diseases in many countries. You can find more information below.
What is neurofibromatosis?
Neurofibromatosis ; is a genetic and neurological disorder that can affect the brain, spinal cord, nerves, and skin. Tumors or neurofibromas (benign tumors) grow along the body’s nerves or under the skin. Scientists have classified neurofibromatosis into two different types; these are type 1 and type 2.
Related article: What are genetic diseases?
Type 1 neurofibromatosis is the most common type worldwide. It occurs in about one in 4,000 births. Type 2 neurofibromatosis occurs less frequently, in one of 40,000 births. Type 1 and type 2 occurrences exist across all racial groups and affect both sexes equally.
Tumors are caused by changes in nerve cells and skin cells. Tumors can also put pressure on vital parts of the body as they increase in size.
Neurofibromatosis can also cause developmental abnormalities or an increased risk of learning disabilities.
Also, other forms of neurofibromatosis have been observed where symptoms are not consistent with type 1 or type 2. A rare form of the disease is known as schwannomatosis . However, no genetic cause for this form has been found.
What are the symptoms of neurofibromatosis?
Type 1 symptoms
Symptoms of neurofibromatosis type 1 include the following items:
- Presence of light brown spots on the skin
- Two or more neurofibromas (pea-sized bumps) that can grow under the skin or in many nerve tissues
- The appearance of freckles in the armpits or groin areas
- The appearance of small pigments in the iris of the eyes (Lisch nodules)
- Tumors along the optic nerve of the eye (optic glioma)
- Severe curvature of the spine (scoliosis)
- Enlargement or malformation (disorder or disability) of other bones in the skeletal system
Symptoms of type 1 neurofibromatosis vary for each individual. Skin-related ones are usually noticed at birth, during infancy, and around a child’s 10s. Between the ages of 10-15, neurofibromas may become evident.
Symptoms such as Lisch nodules may pose minimal or no health risks to a person. Although neurofibromas are usually an aesthetic concern for type 1 patients, they can also be psychologically distressing at times.
For 15 percent of individuals with type 1, visible symptoms can be severely debilitating. Neurofibromas can grow inside the body and affect organ systems.
Hormonal changes during puberty or pregnancy can increase the size of neurofibromas. About 50 percent of children with type 1 have speech problems, learning difficulties, seizures, and hyperactivity .
Type 2 symptoms
Symptoms of neurofibromatosis type 2 include:
- Tumors (schwannoma) around the eighth cranial nerve
- Meningiomas (tumors that form in the membranes surrounding the brain) and other brain tumors
- Tinnitus, hearing loss and deafness
- cataracts at a young age
- Spinal tumors
- balance problems
- Weakening of the muscles (atrophy)
Individuals with type 2 neurofibromatosis develop tumors that grow on the eighth cranial nerves (the nerves that transmit information about hearing and balance from the inner ear structure to the brain) and the vestibular nerves (the nerves responsible for hearing and balance). These tumors cause pressure on the acoustic nerves, which often causes hearing loss. Hearing loss can begin during the teenage years of the individual.
Tinnitus, dizziness, facial numbness, balance problems, and chronic headaches can also occur during the teenage years. Numbness may also occur in other parts of the body due to spinal cord tumors.
The rare form, schwannomatosis, does not affect the eighth cranial nerves, so it does not cause hearing loss. It causes pain in any part of the body. Although schwannomatosis can cause numbness, weakness, or balance problems like type 1 or type 2, the symptoms are less severe.
When should you see a doctor?
It is always useful to see a doctor if you or anyone close to you has the above symptoms related to the disease. Tumors associated with neurofibromatosis are often benign (not cancerous) and have a slow growth rate. For this reason, it is important to get an early diagnosis, as in any disease.
How is neurofibromatosis diagnosed?
Neurofibromatosis is diagnosed from a combination of signs. For children to be diagnosed with type 1 type, they must present at least two of the above-mentioned symptoms associated with type 1. A physical examination is usually performed by a doctor familiar with the disease.
Doctors may use special lamps to examine the skin for spots. Doctors may also order magnetic resonance imaging (imaging) , X-rays , computed tomography (CT scan) , and blood tests to detect defects associated with the disease .
For type 2 neurofibromatosis, doctors will pay close attention to hearing loss. Hearing tests and imaging tests are used to look for tumors in and around the auditory nerves, spinal cord, or brain.
Audiometry (the section that studies hearing measurements and functions of the ear) and brainstem, auditory evoked response tests can help determine whether the eighth cranial nerve is working properly. The presence or absence of the type 2 type of the disease in the family health history is also key for diagnosis.
Genetic testing is also used to diagnose type 1 and type 2. Prenatal testing (prenatal) is useful for identifying individuals with a family history of the disorder but who do not yet have symptoms. However, gene tests are not sufficient to predict the severity of the disease.
Genetic testing is performed by direct gene mutation analysis or linkage analysis. Mutation analysis attempts to identify specific gene changes that cause neurofibromatosis. A linkage analysis is useful if the mutation analysis does not provide enough precise information.
In linkage analysis, multiple family members are bled and tested to trace the chromosome that carries the disease-causing gene for two or more generations. The connectivity test is 90 percent accurate in determining whether individuals have this disease.
Although there is no cure for type 1 or type 2 neurofibromatosis, there are ways to treat the effects of the disease. Surgery may be helpful in removing tumors, but there is a risk that the tumors will regenerate. For optic gliomas (tumors that form in the optic chiasma, where the nerves from both eyes meet), treatment may include surgery or radiation therapy. Treatment for scoliosis may include surgery or back braces.
For type 2-related symptoms, surgery may be a viable option, but complications that may lead to additional hearing or deafness loss remain a risk. Hearing aids are ineffective when parts of the auditory nerve are removed.
With the Auditory Brainstem Implant, approved by the Food and Drug Administration (FDA), some of their auditory nerves have been recently removed, providing a breakthrough for type 2 patients suffering from subsequent hearing loss. The implant transmits sound signals directly to the brain and enables people to hear certain sounds and speech. Radiation therapy can also help relieve symptoms associated with type 2. ( Source )