Fig. 1. Parkinson Diseases Mountain Range model.

Conceptual model assimilating the different diseases within PD to mountains within a range. There are likely many more mountains (diseases) than presented in this conceptual model. The topology of the valley floor represents the total variation in interaction between age, environment, comorbidities, sex and genetics of the population. An individual’s genetic risk is represented by the position in the valley (i.e., basecamp) where the individual starts climbing. Different signals (environment, age, comorbidity) from the dynamic basecamp surroundings interact with the individual’s genetic factors to alter aspects of the disease including onset age at which the patient begins climbing, or whether the individual even develops PD (reflected in the pie charts at base camps). The topology of the mountain (e.g. intrinsic and extrinsic factors) affects how quickly each individual climbs the route (i.e., the rate of disease progression), and thus the range, presentation and severity of symptoms¹⁵. The small boxes (i.e., checkpoints) along the routes of ascent represent potential biomarkers that could be developed/used to provide an unbiased snap-shot that can be used to track disease development within individual patients. However, these ‘on route’ biomarkers will likely change over the course of the disease.