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 MYL3 gene makes a protein called the myosin light chain 3 (MLC3) protein. The MLC3 protein is found primarily in the heart muscles in our body. The MLC3 protein works with other proteins to create the force that is needed for our heart muscles to contract. This muscle contraction is how our heart pumps blood throughout our bodies.
If someone has a harmful change (called a pathogenic variant) in one of their MYL3 genes, then their body does not make as much MLC3 protein as it should. If there is not enough MLC3 protein, then the heart muscles cannot contract as well as they should. This causes damage to these muscles, which can lead to familial hypertrophic cardiomyopathy.
Pathogenic variants in the MYL3 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 MYL3 gene and have the same chances to inherit and pass down pathogenic variants.
Genetic testing for pathogenic variants in MYL3 is currently available, but there are a few different ways to approach testing: