Neurofibromatosis: A Serious Neurological Condition You Must Know About

 

 

A collection of uncommon hereditary illnesses known as neurofibromatosis (NF) impairs the growth of nerve cell tissues or results in tumor formation on nerve tissue. Over 2 million individuals worldwide suffer from a neurofibromatosis mutation; yet, between 30% and 50% of those affected do not have a family history of the disorder. The brain, spinal cord, and nerves are among the parts of the nervous system where these tumors can form.

Globally, NF is more common than the combined conditions of Huntington’s disease, Duchenne muscular dystrophy, and cystic fibrosis. This condition of the nerve system, known as Neurofibromatosis, comes in three forms: NF1, NF2, and schwannomatosis (SWN). While nervous system tumors grow in all three identified forms of neurofibromatosis, there is a strong genetic difference between them. The most prominent common feature of all three is the appearance of Schwann cell–initiated tumorigenesis of the peripheral nervous system.

Why Does Neurofibromatosis Occur?

Genetic mutations, either inherited or arising spontaneously, are the cause of neurofibromatosis. According to the Journal of Medical Genetics, the mutation occurs spontaneously in roughly 50% of cases. Due to the autosomal dominant pattern of inheritance, a child may be affected by the condition even if they inherit only one faulty gene. However, the acquired illness can then be inherited by subsequent generations.

Different gene mutations cause each type of neurofibromatosis:

Neurofibromatosis type 1 (NF1): Chromosome 17 mutations in the NF1 gene lead to aberrant or absent neurofibromin protein, which plays a role in cell division control.

Neurofibromatosis type 2 (NF2): Occurs due to chromosome 22 mutations in the NF2 gene. This results in an aberrant or missing protein called merlin, which also regulates cell development.

Schwannomatosis: Numerous chromosomal 22 mutations can cause Schwannomatosis. A family history of the condition is one of the risk factors for neurofibromatosis. It’s crucial to remember that spontaneous genetic mutations account for between 30% and 50% of instances.

There are further subtypes within these three forms of neurofibromatosis:

Type 1 neurofibromatosis (NF1):

Cutaneous Neurofibromas: These are fleshy, soft tumors that grow directly on the skin or from the sheaths surrounding peripheral nerves.

They frequently show up in early adulthood or late adolescence. Even though they may itch or hurt, they usually don't get malignant.

Subcutaneous neurofibromas: Firm, painful tumors called subcutaneous neurofibromas develop along peripheral nerves that run beneath the skin. They typically show up in teens or early adulthood.

Plexiform Neurofibromas: These rare variations are distinguished by a multinodular, infiltrative development pattern along peripheral nerves. Clinically, they can appear practically anywhere in the body and feel like a "bag of worms." Larger tumors carry a high danger of developing into malignant transformations.

A large Plexiform Neurofibromas grow as a curtain in left eye

Neurofibromatosis Type 2 (NF2): NF2 is characterized by the development of various nervous system tumors as well as bilateral vestibular schwannomas, which are tumors affecting the hearing nerve. Gradual hearing loss, ringing in the ears, unsteadiness, blurred vision, and damage to the facial nerve are among the symptoms.

The rarest type of neurofibromatosis is called Schwannomatosis. Schwannomas, which are benign tumors derived from Schwann cells, are the main cause of it. Chronic pain, numbness, and weakness in different body parts are among the symptoms.

The intensity and specific symptoms of neurofibromatosis might differ greatly amongst affected individuals.

In what ways is neurofibromatosis verified?

The diagnosis of neurofibromatosis is usually made using a combination of clinical examination, biopsy, imaging, and symptoms. Rarely, genetic testing may be carried out to confirm the diagnosis.

Neurofibromatosis type 1 (NF1): Light brown spots on the skin, freckles in the groin and armpit, tiny bumps inside nerves, and scoliosis are signs of NF1. Although most NF1 patients have a decent life expectancy, the illness usually worsens over time.

Neurofibromatosis Type 2 (NF2): Signs and symptoms may include muscle atrophy, flesh-colored skin flaps, hearing loss, and early-onset cataracts. These symptoms might not appear until early adulthood. NF2 raises the possibility of premature mortality.

Schwannomatosis: This type can cause discomfort throughout a large portion of the body or only in one spot. Most of the tumors in NF are not malignant.

In addition to physical and psychological challenges, people with neurofibromatosis may face serious learning, behavioral, and healthcare access issues. An individual with NF should expect to live about 8 years less than the average person.

What is the average age of neurofibromatosis?

The majority of children with neurofibromas are between the ages of 10 and 15. Although NF1 instances can occur at any age, they typically begin in the late 20s or early 30s.

Nearly all NF1 patients will have many neurofibromas by the age of 30, and some will have hundreds. Neurofibromas may gradually enlarge with time. They rarely cause any issues; however, some people could be self-conscious about how they look.

It is rare for the tumors to emerge in late childhood and adolescence, and they hardly ever do so in adults until around age 3.

Having a parent with neurofibromatosis is the only real risk factor for acquiring the disorder. Neurofibromatosis, both type 1 and type 2, is inherited in around half of cases; schwannomatosis is inherited in approximately 15% of instances.

Global prevalence of neurofibromatosis,

Different nations may have varying rates of NF. For instance, the prevalence is 104.1 per 100,000 people in Israel and 12.8 per 100,000 people in Russia.

The most frequent neurological condition, NF1, is caused by a single gene and affects one in every 3,000 newborns. The less common type, NF2, affects approximately 1 in 25,000 persons globally. Regardless of gender or race, NF1 affects roughly one in 2,500 to one in 3,000 persons worldwide. Approximately 1 in 25,000 to 40,000 people have NF2.

Now let’s explore the incidence and prevalence rates of each type in India:

NF1 (Neurofibromatosis Type 1): This is one of the most common Mendelian disorders. The minimal prevalence of NF1 is estimated to be between 1 in 3,000 and 1 in 4,000 persons. About one out of every 2,500 live births has NF1. Recent research suggests that due to genetic testing and improved diagnostic criteria, the incidence rate is likely closer to 1 in 2,000 live births. NF1 is characterized by variable clinical manifestations and autosomal dominant transmission. Mortality tends to rise between puberty and age forty, with a considerable percentage of deaths resulting from serious NF1-related consequences, including vasculopathies and malignant tumors.

Neurofibromatosis Type 2 (NF2): Compared to NF1, NF2 is less prevalent. It is thought to be substantially less common, affecting roughly 1 in 60,000 people. However, due to differences in the populations investigated and case identification techniques, there is a wide range of estimates.

Tumors affecting nerve tissue, especially peripheral and central nerve tissue, are the hallmark of NF2. According to neurosurgeon Dr. Ashok Pillai, one in 2,500 to 4,000 Indians suffer from neurofibromatosis type 1 (NF1). In India, one in 25,000 people has NF2.

Is there a way to treat it?                                                 

For neurofibromatosis, there is currently no recognized cure. However, treatments aim to enhance the quality of life for those affected by controlling and managing symptoms. Here are a few possible treatments:

Surgery: When a tumor becomes malignant or causes issues, surgical removal is frequently employed.

Chemotherapy and Radiation Therapy: If cancer develops, these treatments may be used.

Medication: Several drugs can help reduce nerve pain. These include:

Tricyclic antidepressants (like Amitriptyline), which can treat neuropathic pain.

Anticonvulsants (such as Gabapentin, Pregabalin, Topiramate, Carbamazepine), which help calm the nerves.

Serotonin and norepinephrine reuptake inhibitors (like Duloxetine, Tramadol), a class of antidepressant medications used to treat nerve pain.

Cochlear Implant or Auditory Brainstem Implant: These may benefit individuals with condition-related hearing loss.

It’s crucial to understand that while these therapies can aid in symptom management, the underlying genetic condition remains unaffected. Effective condition management requires routine monitoring and examinations.