Schwannomatosis – Symptoms and Causes
Overview
Schwannomatosis causes slow-growing tumors on nerve tissue throughout the body. These tumors can develop on nerves in the ears, brain, spine, eyes, and peripheral areas.
This rare condition typically appears in early adulthood. Medical experts recognize three distinct types of schwannomatosis, each linked to a specific altered gene.
NF2-related schwannomatosis develops tumors in both ears that may cause hearing loss. The other two types—SMARCB1-related and LZTR1-related schwannomatosis—typically occur without family history.
Most tumors from this condition are benign (non-cancerous). Patients may experience various symptoms depending on tumor location.
Signs and Symptoms
Nerve Tumor Types in NF2
NF2-related schwannomatosis causes slow-growing, non-cancerous tumors in both ears called vestibular schwannomas. These growths develop on nerves that carry sound and balance information to the brain.
Most people notice symptoms in their late teens or early twenties. Common signs include:
- Gradually worsening hearing loss
- Ringing or buzzing sounds in the ears
- Balance problems
- Headaches
NF2 can also cause tumors to grow on other nerves throughout the body. When tumors develop on nerves in the brain, spine, eyes, or outside the central nervous system, they may cause:
- Weakness or numbness in arms and legs
- Persistent pain
- Balance difficulties
- Facial drooping
- Vision changes or cataracts
- Seizures
- Recurring headaches
Gene-Related Schwannomatosis Symptoms
SMARCB1- and LZTR1-related schwannomatosis typically affects adults over age 20, with most symptoms appearing between ages 25-30.
These genetic conditions can cause tumors on nerves throughout the body, including the brain, spine, eyes, and peripheral nerves. The main symptoms include:
- Severe, long-lasting pain that may occur anywhere in the body
- Numbness or weakness in different body parts
- Muscle wasting (atrophy)
Unlike NF2, these forms rarely cause ear tumors. When they do develop, they usually affect only one ear rather than both. This means people with these types typically don’t experience the same hearing problems as those with NF2.
When to Seek Medical Care
Contact a healthcare provider if you experience any symptoms that might suggest schwannomatosis. While there’s no cure for the condition, doctors can treat complications and help manage symptoms effectively.
Early diagnosis allows for better monitoring of tumor growth and more timely interventions when needed. A healthcare professional can also help create a treatment plan to address pain and other difficulties you might experience.
Causes
Schwannomatosis happens when genes change in our bodies. Different genes cause different types of this condition:
- The NF2 gene makes a protein called merlin (or schwannomin) that stops tumors from growing. When this gene changes, the body loses merlin, letting cells grow without control.
- Two other genes—SMARCB1 and LZTR1—can also cause schwannomatosis when they change. Both of these genes normally work to prevent tumors from forming.
Risk Factors
Schwannomatosis can be inherited from a parent through specific gene changes. The inheritance risk varies by type:
- NF2-Related Schwannomatosis: This follows an autosomal dominant pattern, meaning children of affected parents have a 50% chance of inheriting the altered gene.
- About half of people with NF2 received the gene change from a parent. If no relatives have the condition, the person likely developed a new gene change.
- SMARCB1 and LZTR1-Related Schwannomatosis: These types have a lower inheritance risk. Research shows only about 15% of cases are passed from an affected parent to their children.
Medical Complications
Schwannomatosis with NF2 Gene Mutations
People with NF2-related schwannomatosis may develop several health problems:
- Hearing problems ranging from mild to complete loss
- Facial nerve issues affecting facial expressions and movement
- Eye and vision changes
- Skin tumors (benign schwannomas on the skin)
- Neurological symptoms including weakness or numbness in limbs
- Multiple tumors in the brain and spine (meningiomas)
These complications often require multiple surgeries throughout a person’s life to manage tumor growth and related symptoms.
SMARCB1 and LZTR1 Gene-Related Complications
The main complication in these forms of schwannomatosis is severe, debilitating pain. This pain can significantly impact quality of life and daily functioning.
Treatment typically involves surgical removal of problematic tumors. It also includes specialized pain management programs. Ongoing monitoring by medical specialists is also necessary.
