The effect of age and the H1c MAPT haplotype on MAPT expression in human brain.

The MAPT H1c haplotype is a risk factor for the neurodegenerative tauopathies progressive supranuclear palsy (PSP) and Alzheimer's disease. We hypothesise that the effect of the H1c haplotype relates to an increase in MAPT expression leading to an increase in tau neurofibrillary tangle deposition. We have evaluated the effect of the MAPT H1c haplotype on the expression of MAPT using allele specific expression, comparing the relative levels of MAPT H1 and H2 RNA derived from post-mortem human brain, unaffected by neurodegenerative disease. Using three assays spanning the MAPT gene we did not detect any effect of H1c on MAPT expression as compared with other haplotypes. We did, however, detect an effect of age on expression of MAPT H1 with a relative decrease in MAPT H1 expression with increased age. Our data suggest that there is an interaction between age and the expression of MAPT.