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Positive family history of essential tremor influences the motor phenotype of Parkinson's disease
Author(s) -
Hedera Peter,
Fang John Y.,
Phibbs Fenna,
Cooper Michael K.,
Charles P. David,
Davis Thomas L.
Publication year - 2009
Publication title -
movement disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.352
H-Index - 198
eISSN - 1531-8257
pISSN - 0885-3185
DOI - 10.1002/mds.22772
Subject(s) - essential tremor , postural tremor , parkinson's disease , family history , disease , medicine , physical medicine and rehabilitation , movement disorders , degenerative disease , gait , central nervous system disease , psychology , pediatrics , physical therapy
Previous reports have suggested that essential tremor (ET) represents a risk factor for the development of Parkinson's disease (PD). Patients with long‐standing ET who develop PD tend to have a tremor‐dominant subtype. To further clarify this association, we examined patients from kindreds with autosomal dominant ET who had signs of isolated PD but did not meet criteria for overlapping ET. We identified 22 patients with PD meeting these diagnostic criteria, and 90% (20 of 22) had tremor‐predominant subtype of PD. Unilateral rest tremor was the presenting symptom in 15 of 22 patients, bradykinesia or rigidity in 5 of 22, and gait problems in 2 of 22. Postural tremor was relatively mild, and the severity of kinetic tremor tightly correlated with rest tremor ( r = 0.83, P < 0.001). Tremor‐dominant subtype of PD in patients with a positive family history of ET suggests that these patients have inherited a genetic susceptibility factor for tremor, which affects the motor phenotype of PD. © 2009 Movement Disorder Society