b'A diagnosis of NF1 can be given if an individual has 2 or more of the following manifestations. A parent with NF1 based on diagnostic criteriaParent Unaffectedwith NF ParentTwo or more Lisch nodulesYellow-brown dots in theOptic pathway gliomacoloured part of the eye A tumour that grows on the optic nerve and may cause issues with OR two or moreeyesightabnormalities in the choroidThe layer of the eye containing blood vesselsFreckling in the armpit or groin*Six or more cafe-au-lait macules*Brown or beige patches of skin greater than 5mm in children ChildChild Osseous lesions who are pre-puberty or greaterwith NF with NF Unaffected UnaffectedDistinctive abnormalities to thethan 15mm in people who arechild childbones such as bowed legs,post-puberty fractures of the long bones that dont heal, or problems with2 or more neurofibromaUnderstanding the pathway the eye socket tumours of any type, orof the NF1 gene1 plexiform neurofibroma Genetic test are not always required, but they may be suggested when there is no clear diagnosis, possibly because * If caf-au-laits or freckling are present, they should affectvisible symptoms are not obvious or have both sides of the body. When only one side of the body hasyet to develop.these skin changes it may be a sign of mosaic NF1, which Genetic analysis is used to support other only affects part of the body. diagnostic criteria. This means that there must be at least one other diagnostic feature present to conrm NF1.CHTT2204 CTT Booklet A5_v5.indd 8 20/09/2022 16:19'