Parkinson disease(s)

Abstract

The discovery of several monogenic forms has clearly established Parkinson disease (PD) as an etiologically heterogeneous condition.1 However, initial high expectations of well-defined genotype–phenotype correlations have remained largely unmet, both at the clinical and at the pathologic level.2 To date, very few studies have systematically addressed the natural history of genetic PD, resulting in an almost complete lack of longitudinal data on genetic vs non-genetic forms. Likewise, it is currently unknown whether the frequency and type of nonmotor signs, a well-recognized feature of idiopathic PD, might help differentiate genetic from idiopathic PD. These considerations are of major importance as they will not only improve our general understanding of the various forms of PD but will likely also impact on a better prediction of the individual patient's prognosis, on recommendations for genetic testing, and on the choice of therapeutic options including type and doses of antiparkinsonian medication and …