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Título

FRAGILE X-ASSOCIATED TREMOR/ATAXIA SYNDROME: CASE REPORT

RESUMO

CASE PRESENTATION:
A 66-year-old man presented with imbalance and falls, upper-limb tremor and erectile dysfunction for the last two years. Symptoms progressively worsened during the period and patient became more irritable, impulsive and developed impaired memory. Neurological examination revealed ataxic gait, dysmetria, dysdiadochokinesia, bilateral postural and action tremor, and global areflexia with distal lower-limb hypopallesthesia. MOCA test was 19/30 with 11 years of schooling. Brain MRI showed cerebral and cerebellar atrophy, and symmetrical hyperintensities in the middle cerebellar peduncles, periventricular regions and corpus callosum, which was also atrophic (Figure). Electrophysiological study revealed a sensory-motor polyneuropathy. Genetic testing for the fragile X mental retardation 1 (FMR1) gene showed 111 CGG trinucleotide repeats, confirming the diagnosis of fragile X-associated tremor-ataxia syndrome (FXTAS).
DISCUSSION:
FXTAS is caused by the expansion of the CGG trinucleotide in the FMR1 gene (CGG between 55-200 repeats. Clinical picture comprises the presence of one or more characteristics, in different combinations: cerebellar ataxia, parkinsonism, appendicular tremor, neuropathy, dysautonomia, behavioral and cognitive symptoms. Diagnosis is made by major and / or minor clinical and radiological signs : The most important finding is the middle cerebellar peduncles hyperintensities seen on T2-weighted brain MRI sequences. Minor diagnostic criteria include other radiological findings such as white matter hyperintensities and diffuse cerebral atrophy. Corpus callosum atrophy with hyperintensity of the splenium, dentate nucleus and pons may also occur. Definitive diagnosis requires the presence of the premutation associated with the presence of one major radiological sign plus one major clinical symptom or the presence of FXTAS inclusions in neuropathology.
FINAL COMMENTS:
It is to be emphasized the importance of FXTAS investigation in patients with late onset ataxia especially when associated to parkinsonism, tremor and peripheral polyneuropathy. However, there is, at present, no specific targeted treatment for FXTAS and management remains only symptomatic.

Palavras Chave

Fragile X tremor ataxia syndrome, ataxia, tremor