Neurofibromatosis Type 1

What causes NF1?

NF1 is caused by a fault (i.e., mutation) in the NF1 gene. Genes are instructions for cells to make proteins in the body. The NF1 gene is a tumour suppressor gene which normally produces a protein that blocks the development of tumours and cancer. When faulty, it leads to a diagnosis of NF1 and an increased risk of tumours/cancer.

You can undergo genetic testing to understand if you have a faulty NF1 gene. As genes are shared among family, if you have a faulty NF1 gene, it may indicate that other family members may have inherited the faulty gene too and may also be at increased risk of tumours/cancer.

How is NF1 inherited?

NF1 follows a dominant inheritance pattern. This means that having one faulty copy can cause features of NF1.

About half of all people with NF1 have inherited the faulty gene from a parent. The other half have it because of a new and spontaneous change (mutation) in their gene.

Everyone has 2 copies of each gene in their body’s cells:

• 1 copy comes from our father
• 1 copy comes from our mother

A parent with a faulty gene(s) has a 50% chance of passing down their faulty gene(s) to their children. A child, sibling or parent of a family member with a faulty gene(s) has a 50% chance of also inheriting the same faulty gene(s). Extended relatives may also inherit the faulty gene(s).