Mutation Screening of the MAPT and STH Genes in Polish Patients with Clinically Diagnosed Frontotemporal Dementia

Abstract

Frontotemporal dementia (FTD) is a common neurodegenerative disorder and is connected with about 10% of all dementias. In approximately half of all FTD cases, a positive family history has been reported. To date, several mutations at the tau protein gene (MAPT) were identified causing familial and sporadic FTD. Extensive polymorphic variability at the MAPT gene has also been shown to be a risk factor in progressive supranuclear palsy (PSP). The recently described gene Saitohin (STH), located in the intron 9 of MAPT gene, was also reported to be polymorphic. In the present study 23 unrelated Polish patients with clinically defined sporadic and familial FTD were screened for mutations at the MAPT gene. No pathogenic mutations were found in the group. Several novel silent intronic and exonic mutations were identified, most of them associated with two common haplotypes. In the reported group no correlation between extended MAPT haplotype and APOE genotype was determined. There was also no observed relation between age of onset and APOE status. At the STH gene only a common polymorphic change was found. It is postulated that MAPT mutations are not connected with most of the FTD cases in the Polish population.