LRRK2 and Parkinson disease: Importantly, as stated by the original contributors of the raw data, the LRRK2 transgene flies were collected at “a time-point where PD-related phenotypes start to manifest but before pronounced DA neuron loss occurs” [17], which may imply that (1) the downregulation of tyrosine metabolism occurs before pronounced DA neuron loss; (2) we may exclude DA neuron loss as the cause of the downregulation of the tyrosine metabolism in this case; (3) we may conclude that the LRRK2 transgene downregulated tyrosine metabolism in a DA-neuron-loss-independent way, at least in this case.