Left ventricular noncompaction associated with titin-truncating variants in the TTN gene

Aim. To study the association of genetic variants in the titin gene (TTN) with the development and clinical course of left ventricular noncompaction in different age groups.Material and methods. The article discusses three clinical cases of patients with left ventricular noncompaction who were treated at theAlmazovNationalMedicalResearchCenter. We performed a new-generation sequencing of 108 genes associated with cardiomyopathies, as well as whole exome sequencing and Sanger sequencing.Results. We identified genetic variants in the TTN gene leading to the synthesis of truncated protein: in the first two cases, the cause of noncompaction was a thirteen nucleotide deletion with a reading frame shift, in the second, a nonsense mutation. An algorithm for assessing the pathogenicity of the identified variants and a scheme of diagnostic genetic search are presented.Conclusion. Causal role of TTN-truncating variants in development of cardiomyopathies and, in particular, left ventricular noncompaction, requires a comprehensive clinical, segregation and bioinformatic analysis using international databases and the use of bioinformatics software.