The fragile X premutation presenting as essential tremor.
BACKGROUND
The fragile X premutation has recently been reported to be associated with a neurodegenerative syndrome, chiefly characterized by intention tremor, gait ataxia, and executive cognitive deficits in men older than 50 years. Essential tremor is a frequent cause of tremor in elderly patients and in some cases is associated with impaired tandem gait and cognitive deficits.


OBJECTIVE
To describe 2 fragile X carriers whose clinical presentation mimicked essential tremor.


METHODS
The 2 patients described herein underwent neurologic examinations by experienced movement disorders neurologists, magnetic resonance imaging, and fragile X gene, messenger RNA, and protein analyses. One underwent detailed neuropsychological testing.


METHODS
Patients were studied at 2 large university movement disorders clinics.


METHODS
Both patients were white men older than 50 years who had been diagnosed as having essential tremor and then found to be fragile X carriers.


RESULTS
Besides disabling intention tremor, the 2 patients had impaired tandem, generalized brain atrophy, and unusual bilateral T2 middle cerebellar hyperintensities on magnetic resonance imaging. The patient who underwent neuropsychological testing had frontal executive deficits. Both patients had elevated fragile X mental retardation gene 1 messenger RNA and reduced fragile X mental retardation 1 protein levels.


CONCLUSIONS
The fragile X carrier state may underlie the clinical findings in some older men diagnosed as having essential tremor.
Leehey
Maureen A
MA
Department of Neurology, University of Colorado Health Science Center, Denver, CO 80262, USA. maureen.leehey@uchsc.edu
Munhoz
Renato P
RP
Lang
Anthony E
AE
Brunberg
James A
JA
Grigsby
Jim
J
Greco
Claudia
C
Jacquemont
Sebastian
S
Tassone
Flora
F
Lozano
A M
AM
Hagerman
Paul J
PJ
Hagerman
Randi J
RJ
D000368:Aged; D001921:Brain / Q000473:pathology; D003937:Diagnosis, Differential; D005600:Fragile X Syndrome / Q000150:complications* / Q000473:pathology*; D006579:Heterozygote; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014202:Tremor / Q000209:etiology* / Q000473:pathology*