TECRL (trans-2,3-enoyl-CoA reductase like) is an endoplasmic reticulum protein preferentially expressed in cardiac tissue that regulates mitochondrial function and calcium homeostasis in cardiomyocytes 1. The protein possesses very-long-chain enoyl-CoA reductase activity and participates in sphingolipid and fatty acid metabolism [GO annotations]. Mechanistically, TECRL deficiency impairs mitochondrial respiration by reducing ATP production, increasing reactive oxygen species, and decreasing expression of the mitochondrial fusion protein MFN2 and phosphorylated AKT, ultimately promoting mitochondrial apoptotic cascades 2. TECRL regulates these processes primarily through PI3K/AKT signaling and MFN2-mediated mitochondrial fusion 2. Additionally, TECRL deficiency disrupts calcium handling by reducing sarcoplasmic reticulum calcium stores and SERCA/NCX activities, causing abnormal calcium transients 3. Biallelic TECRL mutations cause catecholaminergic polymorphic ventricular tachycardia type 3 (CPVT3), characterized by stress-induced ventricular arrhythmias and sudden cardiac death risk, with phenotypic overlap featuring long QT interval prolongation 34. While homozygous/compound heterozygous mutations cause severe disease, heterozygous carriers typically remain asymptomatic 5. Beta-blockers (nadolol or propranolol) and class Ic antiarrhythmics (flecainide) represent therapeutic options 35.