Neurofibromatosis type I
Neurofibromatosis type 1 (NF1) is a genetic condition that causes tumours (areas of not normal growth) to grow along your nerves. The tumours are usually non-cancerous (benign) but may cause a range of symptoms. NF1 is a condition you're born with, although some symptoms develop gradually over many years. The severity of the condition can vary considerably from person to person.