[Identification of variants in TNNI3 gene in two children with restrictive cardiomyopathy]

To identify the pathogenesis in two patients of restrictive cardiomyopathy (RCM) using high-throughput sequencing.

Peripheral blood samples from the two patients and their parents were collected and genomic DNAs were extracted to conduct targeted next generation sequencing or whole exome sequencing. Bioinformation analysis was performed to identify the pathogenic variants in genes associated with cardiomyopathy, which were further validated by Sanger sequencing.

By high throughput sequencing, we detected a de novo heterozygous variant c.549+1G>T in TNNI3 gene in patient 1. The variant has not been reported previously and was predicted to be pathogenic in line with American College of Medical Genetics and Genomics (ACMG) guidelines (PVS1+PS2+PM2). Another heterozygous variant c.433C>T (p.Arg145Trp) in TNNI3 gene was identified in patient 2 and his father. The variant had been reported as pathogenic variant in Clinvar and HGMD databases; based on ACMG guidelines, the variant was predicted to be likely pathogenic (PS3+PM1+PP3).

TNNI3 variants may be the causative gene responsible for restrictive cardiomyopathy in the two patients. High throughput sequencing results provide bases for the diagnosis of restrictive cardiomyopathy.