Neurofibromatosis is a collective name for a group of genetic conditions affecting the nervous system, which can cause benign tumours (neurofibromas) to develop along peripheral nerves, in both the skin and deeper tissues. The two main types, NF1 and NF2, are genetically distinct conditions and do not occur in the same person. One cannot change into the other (Nerve Tumours UK, 2025), as they are caused by mutations in different genes.

NF1 affects people of all races and sexes equally, with an estimated prevalence of one in 2,500 to 3,000 people. In the UK, about 25,000 people live with NF1, and approximately one child is born with NF1 each day (Nerve Tumours UK, 2025). 

While NF1 is often inherited in an autosomal-dominant pattern, approximately 50% of cases result from spontaneous mutations in the NF1 gene (NINDS, 2025). Diagnosis is based on clinical criteria, including features seen on the skin and in the eyes. At least two of seven key features – such as café-au-lait macules, axillary freckling, neurofibromas, Lisch nodules or optic pathway gliomas (OPGs) – must be present for a diagnosis (Moodley and Lopez, 2024).