The following case study, published in the Cardiogenetics journal, uncovers a unique genetic condition leading to two diseases co-existing in an infant. Ebstein’s anomaly (EA) is a rare anomaly characterized by abnormal apical displacement of the tricuspid valve, leading to tricuspid regurgitation and enlarged right heart chambers. Valve malformations include septal/posterior leaflets abnormally attached, “Atrialization” of part of the right ventricle (RV), and dilated right ventricle and atrioventricular junction. These lead to failure of valve delamination in embryogenesis.
Left ventricular (LV) hypertrabeculation (also called noncompaction cardiomyopathy, LVNC). This condition develops due to the failure of myocardial compaction (weeks 5–8 of embryonic development). It is characterized by Structural abnormalities, which lead to excessive trabeculations (muscle ridges) and deep recesses showing a sponge-like LV appearance.
This case report follows a firstborn via intrauterine insemination. At 18 weeks (18+3 GA), fetal echocardiography showed EA with mild regurgitation and a large, muscular ventricular septal defect (VSD). The fetus compensated well until birth. At birth, diagnosis confirmed: EA + LV hypertrabeculation (noticed postnatally on echo). The infant was discharged on captopril and diuretics.
Echo and MRI imaging revealed EA with displaced tricuspid valve leaflets, atrialization of RV, Large 17 mm apical VSD, and LV hypertrabeculation consistent with noncompaction. Finally, Pulmonary banding was performed at 1 month with regular follow-ups until 17 months.
Whole exome sequencing revealed a new TNNC1 variant (p.Glu66Lys), which codes for Troponin C1 (cTnC). This is a calcium-binding protein crucial for muscle contraction. This variant is rare but carries high risks such as heart failure, sudden cardiac death, surgical challenges, etc. The genetic overlap is explained by the fact that both EA and LV hypertrabeculation are linked to sarcomeric dysfunction. This rare but critical condition demands further research about the same.
