Question 811
{"accessible":false,"alternatives":[{"id":4102,"text":"\u003c1%"},{"id":4103,"text":"5-10%"},{"id":4104,"text":"15-25%"},{"id":4105,"text":"30-50%"},{"id":4106,"text":"60-80%"}],"archived":false,"correctAlternativeId":4102,"explanation":"\u003cp\u003eIDH1 R132H is the most common, but by no means the only IDH mutation. In individuals older than 55-years-of-age who do not have a known pre-existing low-grade glioma, the probability\u0026nbsp;that they harbor a non-IDH1 R132H mutation of IDH1 or of IDH2 is less than 1%. As such, it is felt reasonable to not pursue sequencing in older patients with R132H negative grade 4 astrocytic tuomours, as the yield is very low.\u0026nbsp;\u003c/p\u003e","id":811,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2768","nextQuestionPath":"/articles/glioblastoma-idh-wildtype/questions/810","relatedArticles":[{"id":39154,"title":"Isocitrate dehydrogenase (IDH)","link":"/articles/isocitrate-dehydrogenase-idh-1?lang=us"}],"alsoUsedIn":[],"stem":"\u003cp\u003eA 65-year-old patient with an astrocytic tumor with necrosis\u0026nbsp;is biopsied and the tumor\u0026nbsp;is shown to be IDH1 R132H negative on immunohistochemistry. What is the likelihood that they harbor an alternative IDH1 or IDH2 mutation?\u003c/p\u003e","menuLinks":[{"text":"Report problem with question","url":"https://docs.google.com/forms/d/e/1FAIpQLSfO3soWYhOjJ7yErSysyCe5V4A1CqW7WK3rDA7MtAkecMGqNw/viewform?entry.1624461248\u0026entry.553583435=https://radiopaedia.org/questions/811"}],"attemptsPercentages":[{"alternativeId":"4105","percentage":8},{"alternativeId":"4104","percentage":16},{"alternativeId":"4102","percentage":49},{"alternativeId":"4103","percentage":22},{"alternativeId":"4106","percentage":6}],"promptToLogin":false,"questionManager":false,"articleId":"glioblastoma-idh-wildtype"}