There were two cases of familial Parkinson's disease, a 50-year-old female homozygous for a parkin (PRKN) mutation (c.337-376del) and a 28-year-old female heterozygous for the G51D SNCA mutation.39,40 No other PARK gene mutations or GBA Parkinson's disease risk variants were detected in the Parkinson's disease patients’ cohort. This evidence concerns the gene PRKN and Parkinson disease.