MAPT and tauopathy: In addition, we showed that the MAPT H1 haplotype expresses 40% more exon 10+(4R) MAPT transcript than H2 (Caffrey et al., 2006), and this difference in exon 10+ transcript expression was greater in the globus pallidus than in the frontal cortex, demonstrating a mechanistic link between the regulation of MAPT gene expression by disease-associated polymorphisms and the regional vulnerability exhibited in PSP, a 4R-tauopathy.