International Heart Journal

Featured article

Volume 62 (2021) Issue 2 Pages 359-366

A Novel Titin Truncation Variant Linked to Familial Dilated Cardiomyopathy Found in a Japanese Family and Its Functional Analysis in Genome-Edited Model Cells

Kayoko Hirayama-Yamada, Natsuko Inagaki, Takeharu Hayashi, Akinori Kimura

Dilated cardiomyopathy (DCM) is a common cause of heart failure. TTN, which encodes titin protein, is a representative causative gene of DCM, and is presented mainly as a truncation variant. However, TTN truncation variants are also found in healthy individuals, and it is therefore important to evaluate the pathogenicity of each variant. In this study, we analyzed 67 cardiomyopathy-associated genes in a male Japanese patient who was hospitalized for recurrent severe heart failure and identified a novel truncation variant, TTN Ser17456Arg fs*14. This TTN truncation variant was located in the A-band region. Moreover, the patient's mother with heart failure harbored the same variant, whereas the father and brother without heart failure did not harbor the variant. To examine the functional changes associated with the truncation variant, H9c2 cells were subjected to genome editing to generate cells with a homologous truncation variant. The cells were differentiated using all-trans-retinoic acid, and the mRNA expression of skeletal actin and cardiac actin were found to be increased and decreased, respectively, consistent with known changes in patients with DCM or heart failure. In contrast, another cell with the titin truncation variant used as a control showed no changes in heart failure-related genes. In summary, we found a novel TTN truncation variant in familial DCM patients and confirmed its functional changes using a relatively simple cell model. The novel truncation variant was identified as a pathogenic and disease-causing mutation.

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2021 Volume 62 Issue 2

Mexiletine Shortened QT Interval and Reduced Ventricular Arrhythmias in a Pedigree of Type 2 Long QT Syndrome Combined with Left Ventricular Non-Compaction Bihe Xu, Kun Li, Fang Liu, Lingyun Kong, Jing Yang, Boda Zhou, Tingting Lv, Yuanwei Liu, Fei She, Rong He, Ping Zhang
MicroRNA-665 Regulates Cell Proliferation and Apoptosis of Vascular Smooth Muscle Cells by Targeting TGFBR1 Lang Wang, Jiali Zhou, Fan Guo, Tan Yao, Liang Zhang
Therapeutic Efficacy of Cryopreserved, Allogeneic Extracellular Vesicles for Treatment of Acute Myocardial Infarction Jennifer J. Chung, Samuel T. Kim, Samir Zaman, Mark R. Helmers, Maria F. Arisi, Elizabeth C. Li, Zoe Tran, Carol W. Chen, Peter Altshuler, Minna Chen, Jason A. Burdick, Pavan Atluri
Association of Baseline Anemia with Mid-Term Clinical Outcomes in Patients Who Underwent Trans-Radial Primary Percutaneous Coronary Intervention Kunihiro Kani, Kenichi Sakakura, Yousuke Taniguchi, Kei Yamamoto, Takunori Tsukui, Masaru Seguchi, Hiroyuki Jinnouchi, Hiroshi Wada, Shin-ichi Momomura, Hideo Fujita

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