Neurofibromatosis Causes & Risk Factors

Causes & Risk Factors

To understand the causes and risk factors of NF, genetics and related terminology needs to be understood.

Each cell contains 23 pairs of chromosomes of which one pair differs in males and females, and the rest of the 22 pairs called autosomes are the same in both sexes. About 100,000 genes are arranged on these 23 pairs of chromosomes in a specific order. Different genes have different functions. Gene mutations are changes in gene structure caused by “mutagen” leading to changes in gene instructions to the cell.

Neurofibromatosis is an autosomal dominant disorder meaning, the neurofibromatosis gene located on one of the 22 pairs of genes (autosomes belonging to the mother or father) may cause the disorder to appear in offspring (son or daughter).

The chances of inheriting NF from an affected parent are 50-50 and a faulty gene causes neurofibromatosis. Neurofibromatosis may also occur due to gene mutation and genes may be mutated just before conception leading to the disease in newborns. NF1 is located on chromosome 17 and NF2 is located on chromosome 22 (4) & (6).

It is important to note that the NF1 gene provides instructions for making a tumor suppressor protein called neurofibromin, which is produced by many cells such as nerve cells and specialized cells surrounding nerves (oligodendrocytes and Schwann cells). Mutations to the NF1 gene leads to production of nonfunctional neurofibromin that cannot regulate cell growth and division resulting in formation of tumors called neurofibromas along the nerves throughout the body (7).

Similarly, the NF2 gene provides instructions for making another tumor suppressor protein called Merlin or Schwannomin, which is produced in the nervous system by particular cells called Schwann cells. The Schwann cells surround and insulate nerve cells in the brain and spinal cord. Merlin is believed to control cell movement, cell shape and is involved in inter-cell communication. Mutations to the NF2 gene lead to production of a nonfunctional merlin that cannot regulate growth and division of cells resulting in tumors characteristic of neurofibromatosis type 2 (8).

Conditions & Diseases: Brain & Nervous System

Neurofibromatosis