Human studies of PD patients show that Mn inhalation-exposed subjects have altered DNA methylation (which suppresses transcriptional gene expression, e.g., APC, p16, p53 and RASSF1A) [108,109], histone modifications (e.g., H3K4me2 and H3K9ac on histones from blood leukocytes) [231], miRNA content (e.g., miR-222, miR-21) [232,233], and α-synuclein aggregation-associated miRNA exosome cargo [233]. This evidence concerns the gene SNCA and Parkinson disease.