Neurofibromatosis symptoms can be noticed on time, so know them and their causes, to start treating it right away!
Neurofibromatosis is a disease characterized by the appearance of benign or malignant tumors that affect the central or peripheral nerves. Another of the manifestations that this disease usually causes are spots on the skin due to overpigmentation.
It is a genetic condition. It arises as a consequence of mutations in the genes that code for neurofibromin and merlin. Both molecules act as tumor suppressors by negatively regulating certain oncogenes.
Oncogenes are genes in the human genome that regulate cell growth and proliferation. If these genes get out of control, the cell cycle can get out of control, which implies that the cell in question acquires characteristics of a tumor cell.
Neurofibromatosis symptoms and types
Several types of neurofibromatosis exist. It is possible to differentiate them based on the mutation of the gene.
Also known as von Recklinghausen’s disease. This is the most common of all types of neurofibromatosis; it occurs in 1 in 3 000 people. It gives rise to neurological, cutaneous and even, sometimes, bone or soft tissue manifestations.
In this type, the mutated gene is the one that codes for neurofibromin – more than a thousand possible mutations have been identified, but not all of them give rise to a dysfunctional gene. It is an autosomal dominant disease; that is, the mutations take place on non-sex chromosomes and only the mutation in one of the two alleles is required.
This one is much less common than type I; it occurs in approximately 1 in 35,000 people. It gives rise to bilateral acoustic neuromas, which are tumors that appear on the nerves that connect the ear to the brain.
In this type of disease, the mutated gene is the one that codes for merlin – up to 200 possible mutations have been identified, but again, not all of them give rise to a dysfunctional gene. The vast majority of people with type II neurofibromatosis symptoms have inherited the defective gene from one of their parents.
The manifestations of this disease were previously attributed to type II neurofibromatosis, instead of being considered as a third type of neurofibromatosis. In this case, the mutated gene is SMARCB1, located on the same chromosomal arm as the mutated gene in type II neurofibromatosis.
Advances in the field of sequencing have made it possible to reveal the different genes involved.
Schwannomatosis happens due to the development of neuromas in the peripheral nerves that, in most cases, are truly painful. It is very similar to type II neurofibromatosis, but in this case the characteristic acoustic neuromas do not develop. Furthermore, the clinical picture differs from one type to another.
Peripheral nerve tumors
They are very common in type I neurofibromatosis. They can appear anywhere along the path of the peripheral nerves, which are those that connect the body’s organs and muscles with the central nervous system.
These tumors develop from nerve sheaths – myelin sheaths – a type of tissue that covers neuronal axons, protects them, and facilitates nerve impulse transmission. If we analyze them under the microscope, we can see that they are made up of a mixture of Schwann cells, fibroblasts, neural cells and mast cells.
There are different forms of peripheral nerve tumors:
- Cutaneous neurofibroma. It is soft and meaty.
- Subcutaneous neurofibroma. It is generally hard and has a nodular appearance.
- Nodular plexiform neurofibroma: They can grow towards the intervertebral foramen, thus giving rise to intraspinal tumor masses that can compress the spinal cord and cause great pain.
- Diffuse plexiform neurofibroma. These are subcutaneous nodules due to an amorphous or excessive growth of the bones or underlying Schwann cells.
- Schwannomas: Tumors that derive from Schwann cells. Its malignancy is very rare.
Central nerve tumors
In this case, they arise in the nerves located in the central nervous system – brain and spinal cord. They also come in various forms:
- Optic gliomas: They are the consequence of a lack of control in the cycle of cells astrocytes – a type of nerve cell. Most of the time they are asymptomatic. However, if they grow large enough they can compress the optic nerve and cause blindness.
- Acoustic neuromas: They arise in the nerves that connect the auditory system with the brain. They can cause dizziness, ataxia and even deafness. They are characteristic of type II neurofibromatosis.
- Meningiomas: These tumors develop in the membranes that protect the brain, called meninges. They are usually asymptomatic; however, if the tumor grows large enough it can lead to severe headaches.
In short, neurofibromatosis is a genetic disease that, in most cases, does not trigger in cases of cancer. However, we highly recommend immediate medical analysis to begin the appropriate treatment in time.
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