In addition, genome-wide association studies have found common genetic variants at the LRRK2 locus that increase PD risk in non-familial, sporadic cases (Satake et al., 2009; Simon-Sanchez et al., 2009), suggesting that abnormal LRRK2 function is central to the entire PD disease spectrum (Cookson, 2017). The gene discussed is LRRK2; the disease is Parkinson disease.