How many do we miss? - Evaluation of age at onset and family history as selection criteria for genetic testing in Parkinson’s disease

Current selection criteria (AAO ≤50) identify only a minority (23-32%) of variant carriers. Most carriers (68-77%) present with a later AAO and remain undetected. While AAO is moderately predictive in some cohorts, it insufficiently captures late-onset genetic forms, particularly <i>LRRK2</i>-PD and <i>GBA1</i>-PD. The limited incremental value of FH challenges its use as a selection criterion. These findings support revised, data-driven testing strategies to improve detection of genetic PD across all age groups.