Observational studies described the earlier onset of PD symptoms for patients carrying both LRRK2 G2019S and GBA1 variant [17, 18], while others found inhibition of LRRK2 kinase can normalize the detrimental effect of reduced GCase enzymatic activity in GBA1-mutated astrocytes or iPSC-derived neurons [19]. The gene discussed is GBA1; the disease is Parkinson disease.