What is Neurofibromatosis type I?
[[File:NF-1-Tache cafe-au-lait.jpg|thumb|right|300px|Cafe-au-lait spot]] '''Neurofibromatosis type 1''' (NF1) is a genetic condition that causes [[Tumour|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. In most cases, the skin is affected, causing symptoms such as: * birthmarks known as café au lait spots, which are light or dark brown patches that can be anywhere on the body * soft, non-cancerous tumours on or under the skin (neurofibromas) * clusters of freckles in unusual places – such as the armpits, groin and under the breast * problems with the bones, eyes and nervous system * Certain health problems are often associated with NF1, such as learning difficulties. Less commonly, NF1 is associated with a type of cancer known as malignant peripheral nerve sheath tumours. <!-- ==Causes of neurofibromatosis type 1== NF1 is caused by a faulty gene. If the NF1 gene is faulty, it leads to uncontrolled growth (tumours) developing in the nervous system. In half of all cases of NF1, the faulty gene is passed from a parent to their child. Only one parent needs to have the faulty gene for their child to be at risk of developing the condition. If either the mother or father has the faulty gene, there's a 1 in 2 chance that each child they have will develop NF1. In other cases, the faulty gene appears to develop spontaneously (where there is no family history of NF1). It's unclear why this happens. If you have a child who develops NF1 spontaneously, it's highly unlikely any further children you have will also develop the condition. However, if you do have a child who develops NF1 spontaneously, they could pass on the condition to any children that they have. ==Diagnosis== It's usually easy to diagnose NF1 in adults and older children by checking for the t