No evidence for association of familial Parkinson's disease with CAG repeat expansion.

In some kindreds, familial Parkinson's disease (PD) exhibits genetic anticipation. Thus, we postulated that familial PD in certain kindreds may be associated with a CAG repeat expansion. However, using the repeat expansion detection method, we found no significant increase in the frequency of CAG repeat expansion among 46 unrelated PD probands compared with controls. Nor did we find evidence for CAG repeat expansion between generations in 11 different PD families that exhibit anticipation in age at onset.