A case of Fragile X-associated tremor/ataxia syndrome (FXTAS)

Abstract

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late onset neurodegenerative disorder associated with dysfunction of movement, memory, and the peripheral nervous system. We report an 82 years old male who presented with tremors and difficulty with balance that started at 65 years of age. His motor examination revealed decreased strength in left lower extremity. Tremors were seen in both the upper limbs at rest that worsened with movement. Bilateral lower extremities showed absent vibration and proprioception sensations, absent reflexes and upgoing toes. Electrodiagnostic studies revealed sensory predominant axonal sensory-motor peripheral polyneuropathy. Brain MRI revealed microvascular ischemic changes. The cervical and lumbar MRI showed diffuse degenerative changes. Genetic test for heritable causes of ataxia revealed a premutation in Fragile X gene (84 CGG repeats), confirming the diagnosis of FXTAS. On further genetic testing three out of his four daughters also tested positive for the FMR1 premutation. In appropriate clinical setting, Fragile X-associated tremor/ataxia syndrome (FXTAS) should be considered in every middle aged/elderly patient who presented with slowly progressive ataxia, tremor and peripheral polyneuropathy without any history of cognitive or neurological disabilities in childhood.

Keywords: Ataxia; Fragile X syndrome; Fragile X tremor ataxia syndrome; Genetic testing; Tremor.