In conclusion, our results suggest that olfactory behavioural impairment is a common feature for two Drosophila PD models such as LRRKWD40 and PINK1B9 [46] despite the two opposite electrophysiological peripheral responses and highlight the fact that Drosophila is a powerful model also for the LRRK2 loss-of-function variant. The gene discussed is LRRK2; the disease is Parkinson disease.