Introduction: Frontotemporal dementia (FTD) is a heterogeneous group of diseases with a complex clinical picture, including cognitive decline, behavioral and speech problems, psychiatric symptoms, and parkinsonism. Diagnosis of FTD is complex and requires the use of informative biomarkers.
Methods: We examined 226 Russian patients with FTD (mean age 69±10 years) and estimated the prevalence of the three most common genetic causes—mutations in the C9orf72, GRN, and MAPT genes. We also assessed the role of biochemical biomarkers, such as serum progranulin (PGRN) level and cerebrospinal fluid (CSF) levels of amyloid β (Aβ)-42 and phosphorylated tau protein (p-tau181). 
Results: Mutations in C9orf72, GRN, and MAPT were present in 6%, 12.5%, and 2.5% of patients, respectively. The clinical phenotypes of these patients were described in detail. Low serum PGRN could be used to predict GRN-associated FTD cases. In most cases, we found normal CSF levels of Aβ-42 and p-tau181 except for 6, who had decreased Aβ-42 levels and normal p-tau181 levels.
Conclusion: We have conducted the first study of the genetic structure of FTD in Russia, the results of which, combined with other biomarkers, will help improve the diagnosis of the disease.