Fragile X dementia Parkinsonism Syndrome (FXDPS)

The fragile X-associated tremor/ataxia syndrome is characterized by intention tremor and ataxia in people who are premutation carriers of the Fragile X gene. Patients with this disorder might also demonstrate signs of dementia with parkinsonian features. We report a patient with dementia and parkinsonian signs who did not demonstrate an intention tremor or gait ataxia.

A 58-year-old woman who had 2 sons with fragile X retardation syndrome and was a carrier, developed progressive dementia, including impaired memory, executive dysfunction, nonfluent speech, and parkinsonian signs, but had no action-intention tremor and no gait ataxia. Magnetic resonance imaging revealed extensive abnormalities of the white matter.

On post-mortem examination, 7 years after this evaluation, she demonstrated extensive subcortical white matter pallor (spongiosis) and widespread ubiquitin-positive intranuclear inclusions in both neurons and in protoplasmic astrocytes characteristic of fragile X-associated tremor/ataxia syndrome, but no spongiosis in the cerebellar peduncles a defining feature of this tremor/ataxia syndrome.

Patients who present with dementia and signs of Parkinson syndrome, even in the absence of ataxia or intention tremor should be evaluated for this fragile X dementia parkinsonism syndrome.