How do health care providers diagnose Fragile X-Associated Tremor and Ataxia Syndrome (FXTAS)?

Health care providers can order a blood test to determine if a person who has symptoms of FXTAS is a carrier. A laboratory will conduct the tests to determine what form of the FMR1 gene is present.1 (Read a detailed explanation of the genetics of the FMR1 gene in the section How are genes altered in fragile X-associated disorders?)

However, FXTAS is often misdiagnosed. The condition was identified only recently―in 2001—so it is not as familiar to health care providers as other common disorders in seniors, such as Alzheimer's disease and Parkinson's disease. The similarity of symptoms can lead some health care providers to pursue those conditions before considering FXTAS. Many of the FXTAS symptoms, such as memory problems and balance problems, may also be seen as natural parts of aging.

A health care provider may use a combination of a blood test, symptoms, and information from brain imaging, such as magnetic resonance imaging (MRI), to confirm a FXTAS diagnosis.2 In about one-half of men and one-fifth of women with FXTAS, MRIs show white matter lesions (areas of dead cells) in the middle cerebellar peduncle of the brain.3


  1. National Fragile X Foundation. (2012). Testing. Retrieved August 21, 2012, from https://fragilex.org/learn/testing/ 
  2. Leehey, M. A. (2009). Fragile X-associated tremor/ataxia syndrome (FXTAS): clinical phenotype, diagnosis and treatment. Journal of Investigative Medicine, 57, 830–836.
  3. Finucane, B., Abrams, L., Cronister, A., Archibald, A. D., Bennett, R. L., & McConkie-Rosell, A. (2012). Genetic counseling and testing for FMR1 gene mutations: Practice guidelines of the National Society of Genetic Counselors. Journal of Genetic Counseling, 21(6), 752–760. Retrieved March 21, 2018, from https://fragilex.org/wp-content/uploads/2012/01/Genetic-Counseling-and-Testing-for-FMR1-Gene-Mutations-Practice-Guidelines-of-the-National-Society-of-Genetic-Counselors.pdf  (PDF - 199 KB)