A novel de novo TBX20 variant in a 6-year-old Chinese girl with left ventricular noncompaction: a case report

Abstract

Left ventricular noncompaction (LVNC) is a particular type of cardiomyopathy with an excessively prominent trabecular meshwork and deep intertrabecular recesses in the left ventricle (LV). The clinical manifestation of LVNC is highly variable, ranging from no symptom to congestive heart failure, arrhythmia, thrombosis, and potentially sudden cardiac death. Approximately half of LVNC cases are hereditary. TBX20 is expressed in human embryonic and vertebrate hearts. In this article, we report on a case of pediatric LVNC with a novel de novo TBX20 [c.859C>T, p.(Arg287Trp)] gene variant, which appears to be pathogenic and had not been previously reported in LVNC. The 6-year-old girl was admitted to our hospital for unexplained syncope. 2D-echocardiography revealed a dilated LV with numerous prominent trabeculations, and a two-layered structure, comprising a compacted thin epicardial band and a thicker non-compacted endocardial layer, with deep endomyocardial spaces and intertrabecular recesses in LV. During the follow-up, the child has not shown any obvious clinical signs or symptoms. In this case report, the de novo variant of TBX20 in LVNC expands the spectrum of variants that cause LVNC and contributes to the genetic counseling and individualized treatment of patients. Clinicians should focus on exploring the clinical and genetic characteristics of LVNC to provide therapies and follow-up to improve the outcome.

Keywords: TBX20; case report; exome sequencing (ES); left ventricular noncompaction (LVNC).

Figure 1

Echocardiographic examination of the proband. (A,B) Echocardiography revealed a dilated LV (indicated by the red arrows) and LA; (C) a two-layered structure with a compacted thin epicardial band, a thicker non-compacted endocardial layer and prominent trabeculations in the lower and middle LV (indicated by the red arrows). LV, left ventricle; LA, left atrium; RV, right ventricle; RA, right atrium.

Figure 2

CMR examination of the proband. (A) Some prominent trabeculations and deep perfused intertrabecular recesses were seen in the LV apex and lateral wall (indicated by the red arrows); (B) a compacted thin epicardial band and a thicker non-compacted endocardial layer in the systolic. The short red line illustrates a compacted thin epicardial band and the long red line illustrates a thicker non-compacted endocardial layer. CMR, cardiac magnetic resonance; LV, left ventricle.

Figure 3

The ECG showed T-wave morphology changes in several leads (III, V1, V3, indicated by the red arrows). ECG, electrocardiograph.

Figure 4

A heterozygous variant of the TBX20 gene (c.859C>T, p.R287W) was identified in the proband. Sanger sequencing failed to detect this variant in her parents (indicated by the red arrows).