GBA1 and Parkinson disease: The analysis of individual GBA variants may require larger collaborations; indeed the largest genome-wide association study of PD clinical phenotypes to date included 12 cohorts (including PPMI) and whereas no significant associations were identified with UPDRS motor scores, GBA T369M was shown to be associated with the faster development of H&Y stage 3.24 Alternatively, a more comprehensive assessment of GBA variants using exome sequencing, as done in the present study, could determine whether GBA carrier status affects motor impairment in these cohorts.