Quiz Form

Question Date: 20/06/2023

Question: 60 year old male presented with gradually cerebellar ataxia. He developed tremors in both upper limbs,12-14Hz action + intention tremor, which disappeared at rest. He had recently developed short term memory loss and executive dysfunction. His MRI Brain showed bilateral MCP hyperintense signals. His grandson was diagnosed with autism and daughter had premature menopause. What will the patients genetic testing show?

Options:

• 55-200 CGG repeats in FMR1 gene
• 48-180 CAG repeats in FXTAS gene
• Point mutation in Parkin gene
• Point mutation in DPPX gene

Correct Answer: 55-200 CGG repeats in FMR1 gene

Explaination: The fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder seen in older premutation (55-200 CGG repeats) carriers of FMR1. The premutation has excessive levels of FMR1 mRNA that lead to toxicity and mitochondrial dysfunction. It presents as a spectrum of disorders ranging from ataxia, tremor, fibromyalgia, cognitive dysfunction, parkinsonism, autonomic dysfunction, in elderly. Family history of Fragile X syndrome, premature ovarian failure.

Reference: Cabal-Herrera, A. M., Tassanakijpanich, N., Salcedo-Arellano, M. J. & Hagerman, R. J. Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS): Pathophysiology and Clinical Implications. Int J Mol Sci 21, 4391 (2020).