supravalvular aortic stenosis - caused by mutations in the ELN gene
At least 60 mutations in the ELN gene have been found to cause supravalvular aortic stenosis (SVAS), a heart defect present from birth that is characterized by a narrowing of the large blood vessel that carries blood from the heart to the rest of the body (the aorta). Most of the ELN gene mutations that cause SVAS lead to a decrease in the production of tropoelastin. A shortage of tropoelastin reduces the amount of mature elastin protein that is processed and available for forming elastic fibers. As a result, elastic fibers that make up the aorta are thinner than normal. To compensate, the smooth muscle cells that line the aorta increase in number, making the aorta thicker and narrower than usual. A thickened aorta is less flexible and resilient to the stress of constant blood flow and pumping of the heart. Over time, the wall of the aorta can become damaged. Aortic narrowing causes the heart to work harder to pump blood through the aorta, which can lead to shortness of breath, chest pain, and ultimately heart failure.