Neurofibromatosis Type 1
Updated on April 9th, 2019
Neurofibromatosis type 1 is a genetic disorder that’s caused by a gene mutation. This condition may be passed from parent to child, but about half of the cases occur due to completely new, or spontaneous, gene mutations.
We want you to have the detailed information about genetic conditions so you can prepare and plan for the future. That’s why we put together this detailed guide on neurofibromatosis type 1.
What is Neurofibromatosis Type 1?
Neurofibromatosis type 1 is a rare genetic neurological disorder that can affect your spinal cord, brain, skin, and nerves. The disorder is caused by a genetic mutation of the chromosome 17 gene 1.
This is the gene that produces neurofibromin — a protein that helps to regulate your body’s cell growth.
In people with neurofibromatosis, the mutated gene causes your body to lose neurofibromin. When this happens, your body’s cell growth isn’t controlled and regulated.
Neurofibromatosis type 1, which was known as Recklinghausen’s NF at one time, is the most common type of neurofibromatosis. It occurs in approximately one in every 4,000 births 2.
It’s present across all races and is a condition in which men and women are equally at risk.
For most people, the disorder mainly causes cosmetic concerns. However, about 15% of those with neurofibromatosis type 1 experience symptoms that are severely debilitating, and less than 1% of people with this disorder have malignant tumors that require further medical treatment.
Also, approximately 50% of Children with neurofibromatosis type 1 end up being hyperactive and/or having seizures, learning disorders and/or speech problems 3.
People who don’t experience complications stemming from neurofibromatosis type 1 have a life expectancy that’s almost normal. In fact, with the proper type of education, those with the disorder can live a completely normal life.
Developing rare tumors can shorten the individual’s lifespan, but this is a rare occurrence.
How is Neurofibromatosis Type 1 Inherited?
Neurofibromatosis type 1 has an autosomal dominant pattern of inheritance 4. This means if one parent has neurofibromatosis type 1, the child has a 50% chance of inheriting the condition.
However, the mutated gene is only inherited from a parent in approximately 50% of the cases. The remaining are caused by entirely new gene mutations.
So anyone can develop the condition; it’s not something that only children with affected parents get.
People who are born with neurofibromatosis type 1 are born with one mutated gene in every one of their body’s cells. However, unlike other genetic conditions, you have to have two copies of the mutated gene to get the disorder.
Unfortunately, almost everyone who is born with the disorder eventually develops the second mutated gene. This means if you’re born with the neurofibromatosis type 1 gene, there’s a good chance you’ll develop the disorder, and it’s highly unlikely that someone who doesn’t have the disorder is a carrier of the gene.
Neurofibromatosis Type 1 Symptoms
Symptoms associated with neurofibromatosis type 1 vary from person to person. The symptoms can also vary between people in the same family who all have the NF1 gene.
Some may have dark spots on their skin, while others may notice pea-sized bumps (called neurofibromas) appearing right underneath their skin, connected to nerve tissue. Others may have a combination of symptoms or symptoms that are less or more severe than those of others.
Some neurofibromatosis type 1 symptoms include:
- Dark spots on the skin, known as cafe-au-lait spots
- Pain caused by increasing pressure on the nerves as the affected tissue continues to grow
- Skin growths
- Small, rubbery tumors of the skin, known as nodular neurofibromas
- Large, soft tumors, known as plexiform neurofibromas, which can be dark and spread to the skin’s surface, affecting one’s physical appearance
- Freckles in their groin or underarm area or underneath the breast
- Mild cognitive impairment, including learning disorders and ADHD
- Bowing of the lower leg in early childhood, which could lead to fractures
- Eye tumors such as optic glioma
- Raised, colored spots on the iris of the eye, known as Lisch nodules
- Nerve damage and/or loss of function in the part of the body where the nerves are damaged.
Neurofibromatosis Type 1 Complications
In some cases of neurofibromatosis type 1, the symptoms a person experiences don’t cause any complications.
But complications are possible including:
- Attention deficit hyperactivity disorder (ADHD)
- Fractures and breaks in leg bones that don’t heal very well
- Regrowth of neurofibromatosis tumors
- Scoliosis — a condition that causes the spine to curve
- Cancerous tumors
- Tumors on the skin, face, and other exposed areas of the body
- Blindness caused by a tumor in the optic nerve
- Loss of nerve function caused by pressure being put on the nerves by neurofibroma
- High blood pressure, which develops due to renal artery stenosis or pheochromocytoma
- Hearing loss that results from nerve damage
- Severe pain stemming from the continual growth of nerve tissue.
What Causes Neurofibromatosis Type 1?
Neurofibromatosis type 1 is caused by a mutation in your genes located on chromosome 17. This mutation causes a loss of neurofibromin, which is a protein your body produces that controls cell growth.
When your body loses neurofibromin, your nerve tissue grows uncontrollably.
People who have neurofibromatosis type 1 have a 50% chance of passing the disorder onto their children — and you have a higher risk of developing the disorder if there’s a history of it in your family. However, approximately 50% of new neurofibromatosis type 1 cases occur because of completely new gene mutations 5.
So there’s a chance a person without a family history of the disorder can get it.
Diagnosis of Neurofibromatosis Type 1
Neurofibromatosis type 1 is usually diagnosed by a healthcare provider who treats the condition. In many cases, the diagnosis comes from a developmental pediatrician. However, the disorder may also be diagnosed by a dermatologist, geneticist, or neurologist.
How Do You Diagnose Neurofibromatosis Type 1?
Most cases of neurofibromatosis type 1 are diagnosed when a person has a combination of symptoms present. However, if the diagnosis isn’t clear because the person doesn’t have many symptoms, the doctor may opt to conduct more specific tests.
Testing for neurofibromatosis type 1 includes:
- Eye exam conducted by an ophthalmologist who is familiar with neurofibromatosis type 1
- MRI of the brain or other affected parts of the body
- Genetic tests to locate a mutation of the neurofibromin gene
- Tests that are specific to complications of the disorder.
How Do Doctors Test for Neurofibromatosis Type 1?
Before running more detailed tests, your doctor will conduct a clinical examination. During the exam, the doctor is looking for two or more of the following symptoms:
- Six or more cafe-au-lait spots that measure at least 1.5 cm in adults and at least 0.5 cm in children
- Freckles in the armpits or groin area
- Bone changes such as bowing of long bones
- Optic pathway glioma, which is also known as a visual pathway tumor
- Two or more neurofibromas on or under the skin or one plexiform neurofibroma, which develops in deeper tissue
- Two or more Lisch nodules
- A family history of neurofibromatosis type 1
While a clinical diagnosis is usually a simple and effective way to diagnose the disorder, it’s not always easy to do. In some cases, a person may not have symptoms that are severe enough to determine an accurate diagnosis during a clinical exam.
Also, in children, some signs may not show up until the child is older. This could delay a definitive diagnosis.
If a clinical exam doesn’t yield a firm result, the doctor may order some genetic testing. The test to diagnose neurofibromatosis type 1 analyzes body cells looking specifically for a mutation on the NF1 gene.
The test is simple. It’s completed using a blood sample, which is analyzed to see if the gene is normal or changed.
While genetic testing can be helpful in diagnosing the disorder, results aren’t always clear. When the testing is complete, you’ll receive one of three test results: positive, negative, or inconclusive.
If the test is positive, you have neurofibromatosis type 1. However, the test won’t tell you the type and severity of the symptoms you’ll experience.
Even if you have a family history of the disorder, there’s no way to know what symptoms you’ll have or the severity of them because members of the same family with the same gene mutation can have different symptoms.
Negative test results don’t necessarily mean you don’t have neurofibromatosis type 1. It doesn’t rule the diagnosis out completely because approximately 5% of adults with the disorder have negative DNA test results 6.
In this case, your doctor will most likely give you a probable diagnosis and continue to monitor and treat your symptoms.
Inconclusive DNA test results mean the results were hard to predict one way or another. This is because not every mutation of the NF1 gene causes the disorder.
The gene may have a mutation that’s completely harmless, instead of one that causes neurofibromatosis type 1 symptoms. If you receive inconclusive test results, your doctor may request blood samples from other family members because testing their DNA may tell your doctor if you do, in fact, have neurofibromatosis type 1.
Neurofibromatosis Type 1 Genetics
Neurofibromatosis type 1 is a genetic disorder, meaning that it’s caused by a mutated gene in your DNA. Because of this, genetic testing might help your doctor determine if you have the disorder.
Genetic Tests for Neurofibromatosis Type 1
Your doctor can order a genetic test to determine whether or not you have neurofibromatosis type 1. However, DNA tests are usually only ordered if the diagnosis can’t be confirmed or ruled out during a clinical exam.
DNA tests to detect a mutated NF1 gene are simple blood tests performed in a lab or at your doctor’s office. Once your blood is drawn, it’s sent to the lab where the technician analyzes chromosome 17 to test for any genetic mutations.
DNA testing to Spot or Detect Neurofibromatosis Type 1 Early
In many cases, diagnosis for neurofibromatosis type 1 only requires a doctor to complete a clinical exam. However, this isn’t the case for newborns because some of the disorder’s symptoms can develop as a child ages.
So while a newborn can have cafe-au-lait macules at birth he or she may not have any other symptoms. But the appearance of six or more cafe-au-lait macules could prompt the doctor to order genetic testing.
Between 80 and 85% of children with neurofibromatosis type 1 are diagnosed by age six. By age eight, 95% of children with the disorder have a confirmed diagnosis 7.
If a parent has neurofibromatosis type 1, DNA testing can be completed to determine whether the baby has the gene mutation. However, even if the test determines the baby does have a mutated NF1 gene, there’s no way to tell what type of symptoms the child will develop and the severity of them.
DNA Tests Currently Available for Neurofibromatosis Type 1:
DNA testing is currently available for neurofibromatosis type 1. However, genetic testing isn’t typically ordered unless a doctor can’t rule out the disorder when conducting a clinical exam.
If a test is ordered, your doctor or the lab will take a sample of blood to test. The process requires the lab to analyze the blood to determine if there is a mutated NF1 gene present. If the results are positive, a diagnosis of neurofibromatosis type 1 is confirmed.
When a DNA test for neurofibromatosis type 1 comes back negative, it doesn’t always mean you don’t have the disorder. About 5% of adults with the disorder receive negative DNA tests results.
There’s also a change the DNA test could come back inconclusive. In this case, your doctor may request blood samples from family members to do further testing. If a family history of the disorder can be established and the person has symptoms present, there’s a good chance the doctor will confirm the diagnosis and start testing for symptoms and complications.
Where Can I Go for a Genetic Test for My Child?
If you believe your child has neurofibromatosis type 1, you need to contact your doctor. First, your doctor will conduct a clinical exam to see what symptoms are present and analyze the severity of them.
There’s a good chance your doctor will be able to confirm or rule out the disorder when conducting a physical exam.
Genetic testing is only ordered when a doctor can’t confirm or rule out the diagnosis. However, genetic testing may also be ordered on newborns and children under the age of six in an effort to detect the disorder early.
If a genetic test is ordered for your child, a blood sample will be taken either at the doctor’s office or the lab. Once the test is complete, the lab gives your doctor the test results to discuss with you.
DNA Testing for Neurofibromatosis Type 1: Strengths and Limitations
There are strengths and limitations you should know about before a genetic test is conducted for neurofibromatosis type 1. One of the main advantages of genetic tests conducted for this disorder is that the test can help diagnose a young child who doesn’t have many symptoms of the disorder yet.
Once a mutation is identified, other family members can be tested to determine if they also have a mutation of the NF1 gene. This helps establish a family history of the disorder, which could help with future health or family planning.
Also, genetic testing can be completed on a pregnancy to determine if the child has an NF1 gene mutation.
Unfortunately, there are also a few limitations to using a genetic test for neurofibromatosis type 1. For example, a positive test result won’t tell you what type of symptoms will present themselves or their severity.
It’s also important to note that a negative test result doesn’t necessarily rule out neurofibromatosis type 1. It’s possible to have the disorder and still test negative for it. Also, if the test results are inconclusive, other family members may need to be tested to confirm or rule out the diagnosis.
What Are The Chances That I Will Pass Neurofibromatosis Type 1 On To My Child?
Neurofibromatosis type 1 is considered a genetic disorder that can be passed from parent to child.
If you have this disorder, there’s a 50% chance that your child will have it too 8.
Testing For Neurofibromatosis Type 1 On A Pregnancy Or Before Conception
If you’re concerned that your child will develop the disorder, you can have genetic testing completed during pregnancy.
The test will tell you if your unborn child has a mutated NF1 gene. However, it won’t tell you what symptoms your child will develop or how severe the symptoms will be.
It’s possible for family members with the same NF1 mutations to have different symptoms too. So you can’t assume that your child will have the same symptoms as you if he or she does have the disorder.
Who Does Neurofibromatosis Type 1 Typically Affect?
Neurofibromatosis type 1 isn’t a disorder that discriminates. Anyone, male or female, of any race, can develop the disorder — even children.
The risk of developing the disorder is higher for people when there’s a family history of it present. But about 50% of neurofibromatosis type 1 cases stem from new gene mutations. This means anyone can be born with this condition.
Neurofibromatosis Type 1 Treatment Options
Treatment for neurofibromatosis type 1 revolves around treating the symptoms of the disorder rather than the disorder itself. There isn’t a specific treatment for an NF1 gene mutation.
It’s important for parents of children with neurofibromatosis type 1 to take an active role in the child’s learning process because it is common for kids with the disorder to have learning disabilities and/or ADHD. But with a proper education, people with neurofibromatosis type 1 can lead completely normal lives.
Also, in cases where the disorder causes severe changes in a person’s physical appearance, some sort of depression and anxiety treatment may be necessary. Even though not all cases severely alter one’s physical appearance, the way the disorder affects the skin could affect one’s mental health.
Tumor growth also needs to be monitored closely. While rare, the disorder can cause cancerous tumors to develop 9. Because of this, any tumors that have grown quickly should be removed and a biopsy conducted.
Is Neurofibromatosis Type 1 Treatable?
Neurofibromatosis type 1 isn’t treatable. However, your doctor can treat symptoms stemming from the disease. This may include treatment for depression and/or anxiety, the removal of tumors that could be malignant, and treatment for any pain you experience.
The Prognosis for Neurofibromatosis Type 1
People with neurofibromatosis type 1 who don’t experience any complications with their symptoms have a life expectancy that’s almost normal.
While some may develop learning disabilities, a proper education allows them to lead a completely normal lifestyle because any actual mental impairment is typically mild.
People with this disorder do have an increased risk of developing cancerous tumors though. If this happens, it does typically shorten the person’s lifespan.
Does Neurofibromatosis Type 1 Go Away?
Neurofibromatosis type 1 is a genetic disorder that can’t be treated. It’s not something that will go away on its own. If you’re diagnosed with this disorder it’s something you have for the rest of your life. However, your doctor can help you manage the symptoms stemming from the genetic mutation.
Is There a Cure for Neurofibromatosis Type 1?
There isn’t a cure for neurofibromatosis type 1. In fact, there isn’t a treatment available that treats the disorder. Instead, treatment is focused on managing symptoms of the disorder so that the person affected can lead a normal life.
What Are Neurofibromatosis Type 1 Care Options?
If you have neurofibromatosis type 1, your options for care are limited to treatment for your symptoms.
Unfortunately, there isn’t a treatment that corrects the gene mutation or a medication you can take to control the amount of nerve tissue your body produces. Fortunately, those who don’t experience complications from the disorder can lead completely normal lives and have a life expectancy that’s almost that of a healthy individual.
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