MAPT and Parkinson disease: As with GRN mutations, there is no clear correlation between the type of mutation and the clinical presentation; however, anecdotal observations suggest that exonic mutations that do not affect the splicing of exon 10 are usually associated with a dementia-predominant phenotype, and that intronic and exonic mutations that affect exon 10 splicing, leading to an overproduction of 4R tau, tend to be associated with a parkinsonism-predominant phenotype (Ghetti et al., 2015).