Neurofibromatosis Type 1 with Cutaneous Neurofibromas: Get informed

Neurofibromatosis Type 1, also called von Recklinghausen disease, is one of the most frequent genetic conditions: it affects about 1 in 4,000 people.

It’s an autosomal dominant disorder, which means that the mutation of only one gene allele is enough to trigger the disease. Thus, if one of the parents passes the condition to the child, the child will be affected.

This condition can be of variable intensity: from acute to mild form.  The evolution of the disease is unpredictable, which makes the diagnosis and the follow-up difficult to perform.

Neurofibromatosis is a congenital disease and its symptoms appear in childhood. The symptoms of this condition vary from one patient to another.

Various symptoms of neurofibromatosis

The main symptoms of neurofibromatosis are of cutaneous nature (affect the skin):

- The main characteristic of the disease is the café au lait spots, very well visible on the skin. There are generally 6 of them and they usually appear by the age of 1.

- Lenticular spots situated underarm and on the neck are also present. These spots resemble freckles.

- Tumours called neurofibromas affect the skin. They are often benign. They can be situated on the skin (cutaneous) or under the skin (subcutaneous). There is an increased risk of cancer for subcutaneous neurofibromas. If their size increases or if they become painful, it is necessary to consult a doctor.

Some of the most serious symptoms of neurofibromatosis, apart from cutaneous disorders, are neurological disorders and the development of tumours.

- Tumours related to the nervous system are brain tumours. Neurofibromatosis can therefore in most serious cases lead to mental retardation or learning disabilities.

- Tumours can also develop on certain nerves, especially on the optic nerve. This type of cerebral tumours, called optic pathway gliomas, are not very well-known. They are most common in small children suffering with neurofibromatosis type 1. In 50% of the cases these tumours are asymptomatic (without any symptoms). However, they can cause vision problems.

- Finally, tumours can sometimes appear on the nerve roots of the spinal cord, which can cause motor function disorders.

Other symptoms can also be present. Thus, visceral tumours can appear on the digestive tract, between the lungs or on the bladder.  

Skeletal modifications (bone tumours like pseudoarthrosis, scoliosis), as well as endocrine adenomas (benign tumours that develop on the endocrine glands) and vascular disorders (blood vessels, renal artery) which can lead to arterial hypertension, are also possible symptoms of neurofibromatosis.

However, in most cases neurofibromatosis is a disease with cutaneous symptoms and some benign tumours. Acute manifestations with severe symptoms concern only 15% of patients. The tumours are generally benign.

More about Von Recklingshausen disease

Neurofibromatosis is a genetic disease. The mutation of the NF1 gene, situated on chromosome 17, is responsible for this condition. The task of this gene in ordinary circumstances is to remove tumours by creating protein called neurofibromine. Because of this mutation the protein is incomplete and is not able to prevent the tumours from developing.

Nevertheless, possible mutations of the NF1 gene are very diverse. Neurofibromatosis can have various degrees of intensity and severity, depending on the families. So even though the gene responsible for this mutation has been identified, the scientists cannot predict the form the disease will take (seriousness, intensity).

A hypothesis was made, according to which other genes could intervene with this condition. They would be responsible for the diversity of the forms neurofibromatosis can take. Thus far however, these genes have not been identified.

There is no specific treatment for neurofibromatosis symptoms. A treatment is only necessary in case of a serious symptom aggravation.

To avoid possible complications of neurofibromatosis, a medical follow-up is established. For children, the annual follow-up is recommended, while for adults bi-annual follow-up is sufficient.

Specialised healthcare professionals take care of the neurofibromatosis complications.  For example, a speech therapist accompanies children to help them overcome their learning disability. Chemotherapy can be recommended to deal with the optic pathway gliomas which cause vision troubles.

Finally, even if they are not harmful, cutaneous manifestations of neurofibromatosis are difficult to accept because of their unattractiveness. Psychological support and sometimes surgery to remove the tumours or reduce their size can be suggested.

Source: Orphanet

Published 12 Sep 2019