The dust analysis revealed significantly lower levels of PFBuS (Figure ) in the PD-/LRRK2+ participants compared to the iPD and control groups, while a similar lower trend was found in PD-/LRRK2+ group compared with PD+/LRRK2+. PFBuS is a per-/polyfluoroalkyl substance (PFAS), which is a group of substances of high environmental and toxicological concern due to their long -term environmental persistence and toxicity to organisms, including humans . PFBuS, a relatively shortchain PFAS, is currently used as substitute for PFOS due to lower toxicity and bioaccumulation , . However, adverse effects including cytotoxicity, endocrine disruption, immunotoxicity, reproductive toxicity, hepatotoxicity and neurotoxicity have been associated with PFBuS , .