MYBPC3

The MYBPC3 gene provides instructions for making the cardiac myosin binding protein C (cardiac MyBP-C), which is found in heart (cardiac) muscle cells. In these cells, cardiac MyBP-C is associated with a structure called the sarcomere, which is the basic unit of muscle contraction. Sarcomeres are made up of thick and thin filaments. The overlapping thick and thin filaments attach to each other and release, which allows the filaments to move relative to one another so that muscles can contract. Regular contractions of cardiac muscle pump blood to the rest of the body.

In cardiac muscle sarcomeres, cardiac MyBP-C attaches to thick filaments and keeps them from being broken down. Cardiac MyBP-C has chemical groups called phosphate groups attached to it; when the phosphate groups are removed, cardiac MyBP-C is broken down, followed by the breakdown of the proteins of the thick filament. Cardiac MyBP-C also regulates the rate of muscle contraction, although the mechanism is not fully understood.

familial hypertrophic cardiomyopathy - caused by mutations in the MYBPC3 gene

Mutations in the MYBPC3 gene are a common cause of familial hypertrophic cardiomyopathy, accounting for up to 30 percent of all cases. This condition is characterized by thickening (hypertrophy) of the cardiac muscle. Although some people with familial hypertrophic cardiomyopathy have no obvious health effects, all affected individuals have an increased risk of heart failure and sudden death.

MYBPC3 gene mutations that cause familial hypertrophic cardiomyopathy lead to an abnormally short or otherwise altered cardiac MyBP-C protein. It is unknown how these changes cause hypertrophy of the heart muscle.

other disorders - associated with the MYBPC3 gene

Mutations in the MYBPC3 gene have been associated with other heart conditions. Mutations have been found in people with dilated cardiomyopathy and left ventricular noncompaction. However, the role MYBPC3 gene mutations play in either condition is unclear. Dilated cardiomyopathy weakens and enlarges the heart, preventing it from pumping blood efficiently. Affected individuals have an increased risk of heart failure and premature death. Left ventricular noncompaction occurs when the lower left chamber of the heart (left ventricle) does not develop correctly. The heart muscle is weakened and cannot pump blood efficiently, often leading to heart failure. Abnormal heart rhythms (arrhythmias) can also occur in individuals with left ventricular noncompaction.