A novel TNNI3 gene mutation (c.235C>T/ p.Arg79Cys) found in a thirty-eight-year-old women with hypertrophic cardiomyopathy

We report the case of a thirty-eight-year-old woman admitted to our hospital due to palpitation and chest distress. ST-T segment change was found in her ECG. She was then diagnosed with hypertrophic cardiomyopathy by two-dimensional echocardiography. Physical examination showed no obvious abnormal signs and all laboratory examinations were within the normal range. Myocardial fibrosis was detected by cardiac magnetic resonance imaging (MRI). A novel heterozygous mutation (c. 235C> T/p. Arg79Cys) in TNNI3 for cardiac troponin I was identified in her. Subsequently, her families were investigated. No one died suddenly in her family. Her father, one of her siblings and one of her daughters had the same genetic mutation but with different clinical manifestations while the others were healthy. Her father and brother were also diagnosed with hypertrophic cardiomyopathy with different clinical manifestation. However, the echocardiography of her daughter was absolutely normal. We hypothesized that the Arg79Cys mutation in TNNI3 leads to a slow development of cardiac hypertrophy and the phenotype of this gene mutation is diverse.