Question 820
{"accessible":true,"alternatives":[{"id":4150,"text":"Dandy-Walker malformation"},{"id":4151,"text":"Joubert syndrome"},{"id":4152,"text":"Lhermitte-Duclos disease"},{"id":4153,"text":"pontocerebellar hypoplasia of Barth"},{"id":4154,"text":"rhombencephalosynapsis"}],"archived":false,"correctAlternativeId":4151,"explanation":"\u003cp\u003eJoubert anomaly, also known as vermian aplasia or molar tooth midbrain-hindbrain malformation, is an autosomal recessive disorder where there is a variable degree of cerebellar vermal agenesis.\u0026nbsp;The posterior fossa typically shows a bat wing 4th ventricle and prominent thickened elongated superior cerebellar peduncles giving characteristic molar tooth sign-like appearance.\u0026nbsp;\u003c/p\u003e","id":820,"imageUrl":"https://prod-images-static.radiopaedia.org/multiple_choice_questions/926/images-for-mcqs-1__7__big_gallery.jpeg","imageAttribution":{"kind":"case","rID":53610},"imageAttributionCaseInfo":{"title":"Joubert syndrome","contributor_name":"Sherif Shebl Kotkata","contributor_param":"shsh1981","case_rid":53610,"case_param":"joubert-syndrome-15"},"firstQuestionPath":"/questions/820","nextQuestionPath":"/articles/rhombencephalosynapsis/questions/653","relatedArticles":[{"id":7418,"title":"Joubert syndrome","link":"/articles/joubert-syndrome-1?lang=us"},{"id":15854,"title":"Classification system for malformations of the cerebellum","link":"/articles/classification-system-for-malformations-of-the-cerebellum?lang=us"},{"id":1582,"title":"Dysplastic cerebellar gangliocytoma","link":"/articles/dysplastic-cerebellar-gangliocytoma-1?lang=us"},{"id":37975,"title":"Pontocerebellar hypoplasia","link":"/articles/pontocerebellar-hypoplasia?lang=us"},{"id":4590,"title":"Dandy-Walker malformation","link":"/articles/dandy-walker-malformation-1?lang=us"}],"alsoUsedIn":[],"stem":"\u003cp\u003eA 9-year-old boy presents with nystagmus and ataxia. He is investigated with a brain MRI. What is the most likely diagnosis?\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/820"}],"attemptsPercentages":[{"alternativeId":"4154","percentage":5},{"alternativeId":"4150","percentage":10},{"alternativeId":"4152","percentage":5},{"alternativeId":"4151","percentage":74},{"alternativeId":"4153","percentage":5}],"promptToLogin":false,"questionManager":false,"articleId":"rhombencephalosynapsis"}