Effect of MAPT and APOE on prognosis of progressive supranuclear palsy

To assess genetic influence on the clinical presentation of progressive supranuclear palsy (PSP), the genetic effect on disease course was examined for variants in the tau gene (MAPT) and the gene for apolipoprotein E (APOE) in 58 cases of pathologically confirmed PSP. Clinical indicators of disease course included age at symptomatic onset (AAO), age at death (AAD), and disease duration (DD) and the genetic effects examined included MAPT haplotypes and APOE genotypes. From linear regression analysis, the MAPT H1/H1 genotype was associated with significantly earlier AAO (P = 0.038). The MAPT genotype did not significantly influence DD or AAD. The APOE ε4 allele did not significantly influence AAO, AAD, or DD. Male sex was a predictor for earlier AAO (P = 0.015). The interaction between MAPT and APOE was not significant for AAD and DD, but a significant negative coefficient was found for AAO suggesting their combination does not have an additive effect. These results support the assertion that the H1/H1 genotype may contribute to the earlier occurrence of clinical symptoms.