TGM2 and Parkinson disease: Transglutaminase 2 has been implicated as having a role in various chronic diseases, especially in (a) inflammatory diseases, including wound healing, tissue repair and fibrosis, and autoimmune diseases; (b) chronic degenerative diseases such as arthritis, atherosclerosis, and neurodegenerative conditions like Alzheimer's and Parkinson's diseases; (c) malignant diseases; and (d) metabolic diseases such as diabetes mellitus [28, 78].