GBA1 and Parkinson disease: 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.