Considering that ARSA depletion promoted intracellular accumulation and intercellular propagation of α-synuclein and that lower ARSA level was correlated with cognitive dysfunction in our previous study12, the PD duration-specific pattern of ARSA activity in the current study indicated that deficiency in ARSA activity may lead to detrimental effects on nigrostriatal dopaminergic neurons. Here, ARSA is linked to Parkinson disease.