Fragile X-associated tremor/ataxia syndrome

Case contributed by A.Prof Frank Gaillard


9 year history of progressive Parkinsonian symptoms, dementia, ataxia and peripheral neuropathy.

Patient Data

Age: 75 years
Gender: Male

Generalized cerebral and cerebellar atrophy. Prominent bilateral cerebral white matter low density with some low-density changes extending into the external capsular regions of both basal ganglia. The cerebellum is atrophic. 

Movement degraded study. Diffuse atrophy, most marked in the posterior fossa with there is prominence of the cerebellar folia and fourth ventricle. Relative sparing of the middle cerebellar peduncle is which demonstrates abnormally increased T2 and FLAIR signal (MCP sign).

The medulla is atrophic however the pons appears of normal volume although there is increased T2 signal within the transverse fibers of the pons.

Further confluent abnormal increased T2 and FLAIR signal in the periventricular and subcortical white matter of the cerebral hemispheres including the splenium of the corpus callosum. The cerebral hemispheres also demonstrate atrophy which is most marked in the parietal regions. No evidence of diffusion restriction.

Case Discussion

This patient had a family history of Fragile X syndrome - his grandson was affected. He went on to have genetic testing which revealed an allele size of 95 CGG triplet repeats in his FMRI gene. This allowed the diagnosis of Fragile X-associated tremor/ataxia syndrome to be made. 

Imaging is consistent with this with both major and minor radiological criteria being met:

  • major: MCP sign and high T2 signal in splenium
  • minor: cerebral white matter T2 signal increase, and general severe atrophy
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Case information

rID: 39790
Published: 13th Jun 2016
Last edited: 16th Jul 2018
Inclusion in quiz mode: Included

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