Neurofibromatosis: Symptoms, and Causes

Overview

Neurofibromatosis is a medical condition that is not isolated. This term describes three distinct disorders characterised by the growth of tumours that can impact the brain, spinal cord, and nerves that transmit information from the brain to the spinal cord to every place in the body. While some tumours may develop into malignant (cancerous), the majority are benign (non-cancerous). 

Table of Contents

1. What is Neurofibromatosis?
2. Types of Neurofibromatosis?
3. Causes of Neurofibromatosis
4. Symptoms of Neurofibromatosis
5. Diagnosis of Neurofibromatosis
6. Conclusion
7. Frequently Asked Questions

What is Neurofibromatosis?

Neurofibromatosis is a condition in which tumours develop on nerve tissue that is caused by a class of hereditary illnesses. The brain, spinal cord, and nerves are among the parts of the nervous system where these tumours can form. Neurofibromatosis type 1 (NF1), Neurofibromatosis type 2 (NF2), and schwannomatosis are the three forms of the disease. Children are typically diagnosed with NF1, but early adulthood is typically when NF2 and schwannomatosis are identified.

Usually benign (noncancerous), the tumours associated with these illnesses might occasionally develop into malignant (cancerous). Most symptoms are not severe. Neurofibromatosis can cause hearing loss, learning disabilities, heart and blood vessel issues, blindness, and excruciating pain, among other difficulties.

Types of Neurofibromatosis

Neurofibromatosis can be characterised into three types:

• Neurofibromatosis Type1(NF1): Of the three disorders, neurofibromatosis 1 (NF1) is the most prevalent. 30% to 50% of instances of NF1 are caused by a spontaneous genetic mutation in the NF1 gene, even though many NF1 patients inherit the gene that causes the disorder. The faulty gene can be inherited after this mutation has taken place. There is a 50% probability that a kid of an afflicted parent will inherit the gene mutation. With NF1, children and adults may experience a range of symptoms and health issues that vary with age. The majority of NF1 patients enjoy an average lifespan. Due to the fact that numerous NF1 clinical characteristics evolve at various stage, diagnosing correctly might take years.
• Neurofibromatosis Type2 (NF2): Compared to NF1, neurofibromatosis 2 (NF2) is less frequent. In around half of the cases, the NF2 gene is inherited (familial); in the other half, a spontaneous genetic mutation causes the disorder. A parent with the faulty NF2 gene has a 50% probability of passing it on to each of their offspring.
• Schwannomatosis (SWN): The least frequent form, schwannomatosis (SWN) has several subtypes based on the particular genetic mutation causing it (e.g., SMARC-B, LZTR, XXX). There are instances where there are no symptoms. Others experience chronic discomfort, tingling in the fingers and toes, and slow-growing nerve tumours called schwannomas that are occasionally limited to a single area of the body.

Causes of Neurofibromatosis

Genetic flaws (mutations) that may arise spontaneously during conception or passed on from one’s parents are the cause of neurofibromatosis. Depending on the kind of neurofibromatosis, different genes are involved.

• NF1: Chromosome 17 is home to the NF1 gene. The neurofibromin protein, which is produced by this gene, aids in controlling cell proliferation. The lack of neurofibromin brought on by the mutant gene permits unchecked cell growth.
• NF2: The NF2 gene, which is found on chromosome 22, generates the tumour-suppressive protein Merlin. Uncontrolled cell development results from the mutant gene’s lack of merlin.
• Schwannomatosis: Schwannomatosis is currently associated with two genes. Mutations affecting the tumour-suppressive genes SMARCB1 and LZTR1 are linked to this kind of neurofibromatosis.

Symptoms

Neurofibromatosis type 1(NF1): Symptoms of NF1 consists of:

• Family history of NF1
• The presence of pea-sized bumps (neurofibromas) on or just under the skin
• Six or more café-au-lait spots on the skin 
• Larger patches on or under the skin that appear bloated (plexiform neurofibromas)
• Pigmented lumps on the iris of the eye are called Lisch nodules
• Freckling beneath the arms or in the groin area
• A tumour on the optic nerve may impair eyesight
• Skeletal abnormalities, such as scoliosis, weakening of the shin bone, and bowing of the legs (tibial dysplasia)

Neurofibromatosis type 2 (NF2): Symptoms of NF2 consists of:

• Schwannomas, or tumours along the eighth cranial nerve
• Hearing loss, deafness, or ringing sounds inside the ears (tinnitus)
• Brain cancers, including meningiomas
• Balance issues
• Early-stage cataracts
• Tumours of the spine
• Muscular atrophy, or muscular loss. 

Schwannomatosis: Most cases of this uncommon form of neurofibromatosis occur in adults over the age of 20. It normally takes between 25 and 30 years to show symptoms. Tumours caused by schwannomatosis typically arise on the cranial, spinal, and peripheral nerves, but not on the nerve responsible for transmitting balance and sound information from the inner ear to the brain. People with schwannomatosis do not typically experience the same degree of hearing loss as those with NF2, as tumours do not form on both hearing nerves. However, these are a few symptoms to look out for:

• Severe chronic pain, which can happen anywhere in the body
• Loss of muscular mass
• Numbness or weakness in several body areas

Diagnosis of Neurofibromatosis

Clinical characteristics alone may make it impossible to differentiate between an individual with NF2 and someone with SWN. For those with characteristics of these disorders without a known family history or bilateral vestibular schwannomas (those that affect both sides of the body), genetic testing might be necessary to make the proper diagnosis.

Based on symptoms subsequent imaging and detailed MRI imaging of the brain and spinal cord is required that may reveal schwannomas on peripheral nerves.

Conclusion

Neurofibromatosis is a hereditary condition affecting the neurological system. It primarily impacts the development and growth of nerve cells. It leads to the growth of tumours on nerves. 

Neurofibromatosis can result from a genetic mutation or from inherited neurofibromatosis. You can give it to your kids once you’ve acquired it. The tumours are usually benign, although occasionally they can develop into malignancies.

There are mainly three types of neurofibromatosis:

• Neurofibromatosis type 1(NF1)
• Neurofibromatosis type 2(NF2)
• Schwannomatosis

Frequently Asked Questions

1. When should I consult a doctor?

If you observe any of the following signs of neurofibromatosis on your child’s skin: 

• Six or more café au lait spots
• Skin bumps that are unknown in origin
• Spots in your groin or armpits
• Modifications to your vision or hearing
• Unknown reason for pain
• Weakness in the muscles
• Tingling or numbness in the toes and hands

2. Which is the rarest of the three types of neurofibromatosis?

Schwannomatosis is the rarest of all three types of neurofibromatosis. Though it doesn’t exhibit any symptoms people with schwannomatosis might experience intermittent chronic pain.

3. Is neurofibromatosis a single disorder?

Neurofibromatosis is not a single disorder but a combination of three conditions. These are:

• Neurofibromatosis type 1(NF1)
• Neurofibromatosis type 2(NF2)
• Schwannomatosis