Frontotemporal Dementia in Russia: Genetic Structure, Phenotypic Diversity, and Diagnostic Biomarkers.

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.