Of interest, genome-wide association studies (GWAS) have linked variations in some of these genes (e.g. LRRK2 and SNCA) as risk factors for the development of non-familial PD (Cookson, 2015; Lill et al., 2012; Ross et al., 2011; Satake et al., 2009; Simon-Sanchez et al., 2009), suggesting that shared biological pathways drive disease pathogenesis in both hereditary and sporadic cases (Cookson, 2015; Kluss et al., 2019). The gene discussed is LRRK2; the disease is Parkinson disease.