Since then, several studies have confirmed that irisin plays a protective role in the pathogenesis of many diseases, including neurodegenerative diseases, such as Alzheimer's disease, and cardiovascular diseases (Jin et al., 2018; Kim et al., 2018; Clark and Vissel, 2019; Conti et al., 2019; Young et al., 2019; Zhao et al., 2019). The gene discussed is FNDC5; the disease is Alzheimer disease.