Up to half a million Americans have a hereditary form of heart disease called hypertrophic cardiomyopathy. It can cause irregular heartbeats, problems with the heart's valves, heart failure, and, on rare occasions, sudden death in young people. But some people who carry the genes for this disorder never experience any symptoms. The disease may be modified by a combination of stresses and insufficient levels of a specific protein.
Researchers at Loyola University Chicago Stritch School of Medicine found that environmental stress plays a role in the development of hypertrophic cardiomyopathy in people who carry the genes for it. They performed a procedure that mimics high blood pressure on mice with similar genetic mutations. This caused the mouse hearts to become heavier and decreased their pumping ability. The mice also had lower levels of a protein called cardiac myosin binding protein-C that is critical for the normal functioning of the heart.
The findings suggest that people who have gene mutations for the hypertrophic cardiomyopathy may be at greater risk of developing the condition if they are subject to a variety of environmental stressors, such as high blood pressure, diabetes, and alcohol use. These types of stresses appear to interact with insufficient levels of cardiac myosin binding protein-C, the researchers wrote.
About 1 in 500 people has hypertrophic cardiomyopathy in some form. In this condition, the heart muscle thickens and stiffens, which interferes with the pumping of blood and damages the valves of the heart. Symptoms can include shortness of breath, chest pain, dizziness and fainting, heart failure, and sudden cardiac death. This disorder is the leading cause of heart-related sudden death in people under age 30.
One victim was Boston Celtics star Reggie Lewis, who died at age 27 after collapsing during a basketball session. If a parent has the condition, his or her children have a 50-50 shot of having it.
The study was published in the Journal of Molecular and Cellular Cardiology.
