Our data are consistent with a study from North America that reported similar findings.31 Another study from Germany similarly showed the age of onset in GBA mutation carriers was on average 6 years earlier compared with non-carriers,12 and a previous meta-analysis of several studies showed GBA mutation carriers had an earlier age of onset of around 4.6 years compared with PD patients without GBA mutations.32 Here, GBA1 is linked to Parkinson disease.