The chromosomal region 17q21.31 harbors a 900 kb inversion polymorphism (Stefansson et al. 2005), named after one of the most studied genes in this region because of its plausible association with several neurodegenerative diseases (Ballatore et al. 2007; Arendt et al. 2016): the microtubule-associated tau protein (MAPT) gene. This evidence concerns the gene MAPT and neurodegenerative disease.