Neurofibromatosis is a group of rare genetic disorders that cause benign tumors to form on nerve tissue.
Tumors in this disorder are usually noncancerous (benign), but can sometimes become cancerous (malignant). Symptoms are often mild. However, complications of neurofibromatosis can include hearing loss, learning disabilities, heart and blood vessel (cardiovascular) problems, vision loss, and severe pain.
What is Neurofibromatosis and what are the signs and how to treat it, let’s look at the following article.
Definition of Neurofibromatosis
Neurofibromatosis is a group of genetic disorders that cause tumors to form on nerve tissue. These tumors can develop anywhere in the nervous system, including the brain, spinal cord, and nerves.
There are three types of neurofibromatosis: neurofibromatosis 1 (NF1), neurofibromatosis 2 (NF2) and schwannomatosis. NF1 is usually diagnosed in childhood, while NF2 and schwannomatosis are usually diagnosed in early adulthood.
2 Types of Neurofibromatosis
Some people with this disorder have barely noticeable neurological problems, while others can be very disruptive to a growing child.
There are two main types: neurofibromatosis type I (NF1) and neurofibromatosis type II (NF2), each with different signs and symptoms.
Neurofibromatosis Type 1
NF1 can be diagnosed and seen at birth or during childhood. NF1 is characterized by several light brown (café-au-lait) spots concentrated in the groin and armpits and benign tumors under the skin.
Enlargement and deformity of the bones and curvature of the spine (scoliosis) may also occur. Sometimes, people with NF1 can have tumors in the brain, on the cranial nerves or involving the spinal cord, according to the American Association of Neurological Surgeons website .
Neurofibromatosis Type 2
Neurofibromatosis 2 (NF2) is much less common than NF1. NF2 can appear during childhood, adolescence or early adulthood.
Reported from the AANS website , NF2 is primarily characterized by benign tumors of the nerves that transmit sound impulses and balance signals from the inner ear to the brain. Tumors typically affect hearing and balance (vestibulocochlear) on the left and right (bilateral).
NF2 is also known as vestibular schwannomas. These tumors grow on the nerves that carry sound and balance information from the inner ear to the brain.
Sometimes NF2 can cause schwannoma growths in other nerves, including the cranial, spinal, visual (optic) and peripheral nerves. People with NF2 can also develop other benign tumors.
A third related disorder, called schwannomatosis, has also been recognized.
Schwannomatosis
This disorder is more often diagnosed in adults aged 30 and older and is characterized by benign tumors called schwannomas that affect the nerves.
This rare type of neurofibromatosis usually affects people after age 20. Symptoms usually appear between the ages of 25 and 30, according to the Mayo Clinic health page .
Schwannomatosis causes tumors to develop on cranial, spinal, and peripheral nerves, but rarely on the nerves that carry sound and balance information from the inner ear to the brain.
Tumors usually do not grow on both auditory nerves, so people with schwannomatosis do not experience the same hearing loss as people with NF2.
How Often Does It Happen?
There is a 50 percent chance that a child born to parents with NF1 or NF2 will inherit the gene and develop NF1 or NF2. This is known as an autosomal dominant inheritance pattern.
Tumors in this disorder are very benign and may become malignant in 3 to 5 percent of all cases. About one-third of people with NF have no symptoms.
Neurofibromatosis Type 1
NF1 occurs in about one in every 3,500 births.
Neurofibromatosis Type 2
NF2 is a rare disorder that affects males and females in equal numbers. All races and ethnic groups are equally affected by the disorder.
The estimated incidence of NF2 is 1 in 33,000 people worldwide. Symptoms of the disease usually become apparent during puberty or early adulthood. The average age of onset is 18 to 24 years, according to the Rare Disease website .
Schwannomatosis
Schwannomatosis occurs in about one in every 40,000 births.
Causes of NF1 and NF2
NF is caused by a genetic defect (mutation) that is inherited from a parent or occurs spontaneously at conception.
As reported on the Mayo Clinic page , the specific genes involved depend on the type of neurofibromatosis:
Neurofibromatosis Type 1
The NF1 gene is located on chromosome 17. This gene produces a protein called neurofibromin that helps regulate cell growth. A mutated gene results in the loss of neurofibromin, which allows cells to grow uncontrollably.
Neurofibromatosis Type 2
The NF2 gene is located on chromosome 22, and produces a protein called merlin (also called schwannomin), which suppresses tumors. Mutated genes cause the loss of merlin, leading to uncontrolled cell growth.
Schwannomatosis
So far, there are two genes known to cause schwannomatosis. Mutations in the SMARCB1 and LZTR1 genes, which suppress tumors, have been linked to this type of neurofibromatosis.
Neurofibromatosis Risk Factors
The biggest risk factor for NF is a family history of the disorder. About half of people who have NF1 and NF2 inherited the disease from an affected parent.
People who have NF1 and NF2 and unaffected relatives are likely to have new gene mutations.
NF1 and NF2 are both autosomal dominant disorders, meaning each child of an affected parent has a 50% chance of inheriting the genetic mutation.
The inheritance pattern of schwannomatosis is less clear. Researchers currently estimate that the risk of inheriting schwannomatosis from an affected parent is about 15%.
Neurofibromatosis Diagnosis
Tumors in this disorder are usually non-cancerous (benign), but can sometimes become cancerous (malignant).
Symptoms are often mild. However, complications of neurofibromatosis can include hearing loss, learning disabilities, heart and blood vessel (cardiovascular) problems, vision loss, and severe pain.
Neurofibromatosis Type 1
Neurofibromatosis 1 (NF1) is usually diagnosed during childhood. Signs are often apparent at birth or shortly thereafter and almost always by age 10. Signs and symptoms are often mild to moderate, but can vary in severity.
Signs and symptoms include:
- Flat, light brown spots on the skin (cafe au lait spots).
- Spots in the armpits or groin area.
- Small lumps on the iris of the eye (Lisch nodules).
- Soft, pea-sized lumps on or under the skin (neurofibroma).
- Bone deformities. Abnormal bone development and lack of bone mineral density.
- Tumors of the optic nerve (optic glioma).
- Often there is a specific learning disability, such as problems with reading or math.
- Attention-deficit/hyperactivity disorder (ADHD) and speech delays are also common.
- Larger than average head size.
- Short stature.
Neurofibromatosis Type 2
Signs and symptoms typically appear during late adolescence and early adulthood, and can vary in severity.
As reported on the Mayo Clinic page , signs and symptoms can include:
- Gradual hearing loss
- Ringing in the ears
- Bad balance
- Headache
The diagnosis of NF2 is confirmed by a thorough clinical evaluation and specialized testing (i.e., CT scan, magnetic resonance imaging ( MRI ), pneumoencephalogram, or arteriogram are rarely used today).
Molecular genetic testing for mutations in the NF2 gene is available for most affected individuals who have a positive family history, according to the Rare Disease website .
Neurofibromatosis Treatment
NF treatment focuses on promoting healthy growth and development in affected children and on early management of complications.
When NF causes large tumors or tumors that press on nerves, surgery can relieve symptoms.
Some people may benefit from other therapies, such as stereotactic radiosurgery or medications to control pain.
New drugs to treat tumors in children, and other new treatments are being developed.
Neurofibromatosis Type 1
Children with NF1 should be screened for height, weight, head circumference, evidence of normal sexual development, signs of learning disabilities and/or behavioral problems.
They should have skin checks for growth, spots, scoliosis , blood pressure, vision and hearing loss screening. Any unusual growth patterns are generally investigated.
Early or late puberty may also indicate further study. Diagnostic evaluations such as blood tests, X-rays, and other tests may be ordered if there are additional concerns. Healthy children with NF1 are usually seen at six- or 12-month intervals, according to the AANS website .
Adults with NF1 typically have a standard physical evaluation and skin exam for growth, freckles, scoliosis, blood pressure, vision and screening for hearing loss.
Doctors should also be alert for new masses or enlargements or new symptoms in general. Adults with NF1, who are otherwise healthy, usually have annual checkups.
Neurofibromatosis Type 2
Treatment for vestibular (acoustic) neuroma associated with NF2 is surgical removal of the tumor, if possible. The surgical procedure performed is based on the exact size and location of the tumor.
Radiation therapy may be considered for some individuals with this disorder, especially those who are not candidates for surgery. The VEGF inhibitor bevacizumab may also be considered for treating rapidly growing schwannomas but is very expensive, according to the Rare Disease website .
Routine monitoring may be necessary for affected or at-risk individuals. Annual magnetic resonance imaging (MRI) may be needed starting around age 10 to 12 years and continuing through at least the fourth decade of life in addition to regular hearing evaluations.
Early diagnosis and appropriate treatment can improve survival in those affected. Genetic counseling is recommended for people with NF and their family members.
That is the information related to neurofibromatosis which is classified as a rare disease. Hopefully this information is useful.
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Republished with permission from theAsianParent Indonesia
