Schwannomatosis

Schwannomatosis is a rare condition where slow-growing tumors form on nerve tissues. These tumors can develop on nerves throughout the body, including those in the ears, brain, spinal cord, eyes, and the nerves outside the brain and spinal cord (called peripheral nerves). It's typically diagnosed in young adulthood.

There are different types of schwannomatosis, each linked to a specific gene change.

One type, called NF2-related schwannomatosis, is associated with the NF2 gene. Tumors in this type often appear in both ears, potentially leading to hearing loss. Sometimes, this altered gene is inherited from a parent. Previously, this type was known as neurofibromatosis 2 (NF2).

The other two types, SMARCB1-related schwannomatosis and LZTR1-related schwannomatosis, are usually not inherited from family members. These types are linked to changes in the SMARCB1 and LZTR1 genes, respectively.

Importantly, the tumors in schwannomatosis are generally not cancerous. Symptoms can vary and include headaches, trouble hearing, balance problems, and pain. Treatment focuses on managing these symptoms, rather than directly removing the tumors. Doctors work to ease the discomfort and improve quality of life.

Schwannomatosis is a condition where tumors grow on nerves. These tumors are non-cancerous (benign). The symptoms depend on the specific type of schwannomatosis and where the tumors grow.

NF2-related schwannomatosis often starts with slow-growing tumors, called acoustic neuromas or vestibular schwannomas, in both ears. These tumors develop on the nerves that send sound and balance information to the brain. This can lead to a range of symptoms, usually appearing in late teens or early adulthood:

• Gradual hearing loss: Sound becomes harder to hear over time.
• Ringing in the ears (tinnitus): A constant buzzing or ringing sound.
• Poor balance: Difficulty maintaining stability.
• Headaches: Pain in the head.

These tumors can also grow on nerves elsewhere in the body, like the brain, spinal cord, and eyes. People with NF2 may also develop other benign tumors in various parts of their bodies. Symptoms of these tumors may include:

• Numbness and weakness in limbs: Loss of feeling or strength in the arms and legs.
• Pain: Discomfort in different parts of the body.
• Poor balance: As mentioned above.
• Facial drooping: One side of the face sagging.
• Vision changes or cataracts: Problems with sight or cloudy eye lenses.
• Seizures: Sudden, uncontrolled electrical activity in the brain.
• Headaches: As mentioned above.

SMARCB1- and LZTR1-related schwannomatosis typically affects people after age 20, with symptoms usually appearing between 25 and 30. These types of schwannomatosis can cause tumors to grow on nerves in the brain, spinal cord, and eyes. Tumors can also grow on nerves outside the brain and spinal cord. This type often causes:

• Persistent, disabling pain: Long-lasting pain that can occur anywhere in the body and significantly affect daily life.
• Numbness or weakness: Loss of feeling or strength in various parts of the body.
• Muscle wasting (atrophy): Loss of muscle mass.

Tumors in the ears are less common with this type of schwannomatosis, and if they do occur, they usually grow in only one ear, unlike NF2. This difference means that hearing loss isn't a typical symptom.

Important: If you experience any of these symptoms, it's essential to see a doctor. While there's no cure for schwannomatosis, treatments can help manage the complications and improve quality of life.

If you have symptoms of schwannomatosis, it's important to see a doctor. While there's no known cure for schwannomatosis, doctors can treat any problems or complications that arise. This means that even though you can't get rid of the condition itself, you can manage its effects and improve your quality of life by getting medical care.

Schwannomatosis is a condition where tumors grow in the nerves. The reason for this uncontrolled growth is a problem with specific genes in our DNA.

Some cases of schwannomatosis are linked to a change in the NF2 gene. This gene normally makes a protein called merlin (also known as schwannomin). Merlin helps control cell growth, preventing tumors from forming. When the NF2 gene is altered, it can't make enough or any merlin. This lack of merlin allows cells to grow out of control, leading to tumors.

Other types of schwannomatosis are connected to changes in either the SMARCB1 gene or the LZTR1 gene. These genes, like NF2, also normally help control cell growth and prevent tumors. When these genes are altered, they can't do their job as effectively. This can also lead to uncontrolled cell growth and the formation of tumors. So far, scientists have identified SMARCB1 and LZTR1 as two genes that, when altered, contribute to this type of schwannomatosis.

Some types of schwannomatosis, a condition that causes tumors, can be inherited. This means a person can get the genes that cause the problem from a parent. The way the gene is passed down, and therefore the chance of inheriting it, depends on the specific type of schwannomatosis.

In general, autosomal dominant conditions mean that only one copy of a changed gene is needed for the person to have the condition. This changed gene is located on one of the non-sex chromosomes (autosomes). If a parent has this kind of changed gene, there's a 50% chance their child will inherit it. So, if a parent has an autosomal dominant condition like one type of schwannomatosis, there's a 50% chance their child will also have it. This means that for half of people with a type of schwannomatosis related to a gene called NF2, they got the changed gene from a parent. If the parent has NF2, their child has a 50% chance of inheriting the changed gene and developing the condition.

However, for other types of schwannomatosis, like those linked to the SMARCB1 or LZTR1 genes, the chance of inheriting the condition from an affected parent is much lower. Researchers estimate this risk is around 15%. This means that in most cases of SMARCB1- and LZTR1-related schwannomatosis, the changed gene wasn't inherited from a parent, but instead happened as a new change in the child's genes.

Schwannomatosis, a condition causing tumors, can have various complications. These complications differ depending on the specific type of schwannomatosis a person has.

One type of schwannomatosis, related to a condition called Neurofibromatosis type 2 (NF2), can lead to a number of problems. These can include:

• Hearing loss: This can range from a slight decrease in hearing to complete loss.
• Facial nerve issues: Damage to the facial nerves can cause weakness or problems with facial movement.
• Vision problems: Changes in vision can occur.
• Skin tumors: Small, harmless tumors called schwannomas can appear on the skin.
• Numbness or weakness in limbs: This can affect the legs or arms, causing discomfort and reduced movement.
• Brain and spinal tumors: People with NF2-related schwannomatosis can develop many benign tumors (called meningiomas) in their brain and spinal cord. These tumors often require repeated surgeries to manage them.

The pain associated with this type of schwannomatosis can significantly impact a person's daily life. This pain can be debilitating. Managing this pain often requires help from a pain management specialist, and sometimes surgery.

Doctors use several steps to diagnose schwannomatosis. First, they'll ask about your health history, both yours and your family's, and do a physical exam. This helps them understand your symptoms and look for any physical clues.

Sometimes, more tests are needed to figure out if the schwannomatosis is linked to specific genetic conditions, like NF2, SMARCB1, or LZTR1. These tests can help determine the cause and guide treatment.

These additional tests might include:

• Eye exam: This check can find problems like cataracts or vision loss, which can sometimes be related to schwannomatosis.

• Hearing and balance tests: These tests help assess hearing and balance. Audiometry measures hearing, while electronystagmography tracks eye movements to evaluate balance. A brain stem auditory evoked response test measures the electrical signals that carry sound from your inner ear to your brain. Any unusual results in these tests might point to schwannomatosis.

• Imaging tests (X-rays, CT scans, MRIs): These tests create pictures of the inside of your body. They can show changes in your bones, or help spot tumors in the brain, spinal cord, or other areas. Finding and monitoring these tumors is a crucial part of managing schwannomatosis. These images are often used to track the disease's progression after a diagnosis.

• Genetic tests: Genetic tests can sometimes show if the schwannomatosis is related to specific genes like NF2, SMARCB1, or LZTR1. However, other genes not yet discovered might also be involved. Some people choose genetic testing before starting a family to assess their risk of passing on the condition.

It's important to remember that not every case of schwannomatosis is caused by a known gene. Doctors use a combination of these tests to get a complete picture of your condition and develop the best treatment plan.