GBA1 and Parkinson disease: One study examining the underlying molecular mechanisms of the strongest common genetic risk factor for PD, the glucocerebrosidase gene (GBA) encoding the lysosomal enzyme GCase, reported that the heterozygous GBA-N370S mutation caused dopaminergic neuronal malfunction as evidenced by the retention of misfolded GCase proteins in the ER, disrupted dopaminergic neuronal proteins, ER stress, autophagy/lysosome dysfunction, and increased α-synuclein release, eventually leading to preferential dopamine neuronal vulnerability in PD (75).