MAPT and frontotemporal dementia: Like many other familial FTD mutations (Denk and Wade-Martins, 2009), N296H causes increased inclusion of MAPT exon 10, leading to an overrepresentation of tau isoforms with four microtubule-binding repeats, known as 4R tau (Grover et al., 2002; Yoshida et al., 2002).