We have over 20,000 different genes in the body. These genes are like instruction manuals for how to build a protein, and each protein has an important function that helps to keep our body working how it should. The CASQ2 gene makes a protein called calsequestrin 2. The calsequestrin 2 protein helps to store calcium. The amount of calcium in the cells of our heart controls when our heart muscles contract and relax, which make the heart beat at a normal rhythm, The calcium that is stored by the CASQ2 gene is primarily in the heart muscles.
If someone has a harmful change (called a pathogenic variant) in one of their CASQ2 genes, then their body is not going to make enough of the calsequestrin 2 protein as it should. If there is not enough calsequestrin 2 protein, then there will not be enough stored calcium. This would mean that the heart’s ability to contract and relax (and thus beat) at a normal rate is not going to work as well as it should. This can lead to a heart condition called catecholaminergic polymorphic ventricular tachycardia.
Pathogenic variants in the CASQ2 gene are passed through a family in an autosomal dominant pattern, meaning that anyone who carries the variant has a 50% chance to pass it down to any children they have. Women and men both have the CASQ2 gene and have the same chances to inherit and pass down pathogenic variants.
Genetic testing for pathogenic variants in CASQ2 is currently available, but there are a few different ways to approach testing: