Gene promoter methylation and expression of Pin1 differ between patients with frontotemporal dementia and Alzheimer's disease

•Frontotemporal dementia (FTD) and Alzheimer disease (AD) show fibrillar aggregates.•Pin1 facilitates tau dephosphorylation playing a neuroprotective function.•A higher methylation in three CpG sites at PIN1 promoter was seen in FTD patients.•We found a lower gene expression of Pin1 in FTD patients than AD patients.•Pin1 has an important but distinct involvement in these two types of dementia.

Frontotemporal Dementia (FTD) and Alzheimer's Disease (AD) share the accumulation of fibrillar aggregates of misfolded proteins. To better understand these neurodegenerative diseases and identify biomarkers in easily accessible cells, we investigated DNA methylation at Pin1 gene promoter and its expression in peripheral blood mononuclear cells of FTD patients. We found a lower gene expression of Pin1 with a higher DNA methylation in three CpG sites at Pin1 gene promoter analysed in FTD subjects, in contrast to a higher gene expression with a lower methylation in AD subjects and controls. These data suggest an important and distinct involvement of Pin1 in these two types of dementia.