Clinical Genetic Characteristics of Epilepsy Due to Mutations in the PCDH19 Gene (OMIM: 300088)

Objectives: to analyze the clinical genetic characteristics of PCDH19 -associated epilepsy in a cohort of patients from the population of the Russian Federation. Materials and methods. The cohort of patients with early epileptic encephalopathy consisted of 16 patients aged from 10 months to 30 years. All patients underwent neurological examination by standard methods, exome sequencing, and electroencephalogram monitoring. Results. Most of the mutations detected were frameshift mutations or mutations forming a stop codon. Six were duplications and four were deletions of a single nucleotide, while three were nonsense mutations. Polymorphism in the clinical manifestations of convulsions were found, which were independent of the type of mutation and its location, which is consistent with results reported by other authors. Conclusions. This study of the clinical genetic features of our patients leads to the conclusion that the PCDH19 gene has so-called hot spots, which are mutated more frequently than other parts of the gene, and that the clinical picture of epileptic encephalopathy type 9, induced by mutations in the PCDH19 gene, is variable.