Genetic variants, including pathogenic mutations in leucine-rich repeat kinase 2 (LRRK2) [12] and glucocerebrosidase beta 1 (GBA1) genes [13], further modulate PD risk and progression, with emerging evidence linking them to metabolic dysregulations in caffeine and other pathways [14,15,16], but there remains limited evidence supporting their ability to predict disease progression [17]. This evidence concerns the gene LRRK2 and Parkinson disease.