CASQ2

Catecholaminergic polymorphic ventricular tachycardia

At least 30 mutations in the CASQ2 gene have been identified in people with catecholaminergic polymorphic ventricular tachycardia (CPVT). Some of these mutations change single protein building blocks (amino acids) in the calsequestrin 2 protein, while other mutations prevent the cell from producing any functional calsequestrin 2. Studies suggest that the altered or missing protein is unable to perform its usual roles in calcium binding within myocytes. A lack of properly functioning calsequestrin 2 may also affect regulation of the RYR2 channel, allowing calcium ions to "leak" out of the sarcoplasmic reticulum. These changes disrupt the careful control of calcium ion flow within myocytes, which can trigger an abnormal heart rhythm in people with CPVT.