Familial Aggregation and Co-Aggregation of Essential Tremor and Parkinson's Disease.

Certainly we see this in the clinic sometimes...

Neuroepidemiology. 2015 Nov 26;46(1):31-36. [Epub ahead of print]

Louis ED, Clark L, Ottman R.

http://www.karger.com/Article/Abstract/442021

BACKGROUND:

Current data suggest that the 2 common tremor disorders, essential tremor (ET) and Parkinson's disease (PD), may be associated with one another. Familial aggregation studies allow one to further explore their relatedness.

METHODS:

Probands with ET (n = 110), PD (n = 130) or both ET and PD (n = 27) and control probands (n = 177) reported whether they had relatives with these diseases or with non-specific tremor.

RESULTS:

A greater proportion of ET probands than control probands reported relatives with ET (30.0 vs. 2.8%, p < 0.001), non-specific tremor (38.2 vs. 13.6%, p < 0.001) and both ET and PD in different relatives (6.4 vs. 0.6%, p = 0.004). A greater proportion of PD probands than control probands reported relatives with PD (20.0 vs. 8.5%, p = 0.003), ET (11.5 vs. 2.8%, p = 0.002) and both ET and PD in different relatives (6.9 vs. 0.6%, p = 0.002).

CONCLUSIONS:

This study provides evidence for the aggregation of ET in ET families and PD in PD families, and the familial co-aggregation of ET and PD.