How to diagnose Neurofibromatosis type 1 ?
Is genetic testing available for neurofibromatosis type 1? Although it is usually not necessary for diagnosis, genetic testing is available for NF1, the gene known to cause neurofibromatosis type 1. Carrier testing for at-risk relatives and prenatal testing are possible if the disease-causing mutation in the family is known. The Genetic Testing Registry (GTR) is a centralized online resource for information about genetic tests. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional. How is neurofibromatosis type 1 diagnosed? The diagnosis of neurofibromatosis type 1 (NF1) is usually based on the presence of characteristic signs and symptoms. Specifically, doctors look for two or more of the following features to make a diagnosis of NF1: Six or more cafe-au-lait spots (measuring more than 5 mm across in children and more than 15 mm across in adolescents and adults) Two or more neurofibromas of any type or one plexiform neurofibroma (a neurofibroma that involves many nerves) Freckling in the underarm and/or groin Optic glioma Two or more Lisch nodules (clumps of pigment in the colored part of the eye that do not interfere with vision) Bone abnormalities including sphenoid dysplasia (absence of bone surrounding the eye) or tibial pseudarthrosis (incomplete healing of a fracture) A parent, sibling, or child who has been diagnosed with NF1 Because many of the features associated with NF1 develop with age, it can sometimes take several years to make a diagnosis in children without a family history of the condition. Genetic testing for changes (mutations) in the NF1 gene is available, but it is often not necessary. Prenatal testing and preimplantation genetic diagnosis is only an option if the disease-causing mutation in the family is known.