Genetic analysis of a Turkish dementia cohort

This is a guest post by Gamze Guven, MSc, PhD from Istanbul University and a visiting fellow at TheGBLab.

Gamze

We have recently published the first molecular study analysing the main Frontotemporal dementia (FTD) related genes in a Turkish cohort of dementia patients.

Our aims were to identify pathogenic mutations and novel variants and to determine the frequency of genetic mutations in the major frontotemporal dementia genes (MAPT, GRN and C9ORF72) in the Turkish dementia population. In a collaboration between UCL and Istanbul University, we have performed whole exome sequencing in 93 Turkish index patients mostly diagnosed with Alzheimer’s disease or FTD. We have identified one pathogenic mutation (p.P636L) and one novel missense variant (p.D13G) in MAPT; a probably pathogenic splice site deletion in GRN and GGGGCC expansions in the non-coding region of C9ORF72. The overall mutation rate (5.4%) found in our study showed that MAPT, GRN and C9ORF72 pathogenic mutations are not uncommon in this population in a cohort with different types of dementia.

Given the frequency of variants identified in this and previous (Lohmann E. et al., 2012) studies, a standardized molecular screening procedure for all dementia genes should be implemented in Turkey. The high birth rate in Turkey make these studies of particularly importance given the potential high impact in genetic counseling and clinical management of FTD and dementia families.