Bicuspid aortic valve (BAV) is a congenital heart condition affecting the aortic valve, which controls blood flow from the heart to the body’s main artery, the aorta. Normally, the aortic valve has three leaflets that open and close to regulate this flow. In individuals with BAV, the valve has only two leaflets instead of the usual three, making it one of the most common heart defects present at birth, affecting approximately 0.5% to 2% of the general population.
Understanding Bicuspid Aortic Valve
The aortic valve’s primary role involves ensuring oxygen-rich blood efficiently leaves the heart and travels to the rest of the body while preventing blood from flowing backward. With only two leaflets, a bicuspid valve may not open and close as effectively as a three-leaflet valve. This can lead to various issues, such as the valve becoming stiff and narrowed, a condition known as aortic stenosis, or failing to close tightly, causing blood to leak backward into the heart, which is called aortic regurgitation.
Many individuals with BAV remain without symptoms for years, often not realizing they have the condition until adulthood. However, as the valve’s function changes over time, symptoms such as chest pain, shortness of breath, fatigue, or fainting may emerge. BAV can also increase the risk of other complications, including enlargement of the aorta (aortopathy), which can lead to more serious issues like aortic aneurysm or dissection, and a higher susceptibility to heart valve infections.
The Genetic Link to Bicuspid Aortic Valve
Bicuspid aortic valve often has a genetic basis, meaning it can be passed down through families. This inheritance commonly follows an autosomal dominant pattern, meaning a person needs only one copy of an altered gene from either parent to be predisposed.
Even with a genetic predisposition, the condition shows incomplete penetrance, which means not everyone who inherits the genetic change will develop BAV, or they may experience varying degrees of its severity. Multiple genes and environmental factors can interact, and while the full genetic picture is still being understood, research has identified certain genes like NOTCH1 and ACTA2, though these account for only a small percentage of cases. The high heritability, estimated to be as high as 89%, suggests that genetic factors are highly influential in its development.
Bicuspid Aortic Valve Without a Family History
Not all instances of bicuspid aortic valve are inherited; some individuals develop BAV sporadically. While genetic factors play a significant role in many cases, the precise reasons for sporadic BAV are less understood. The absence of a family history does not exclude the possibility of having BAV, as other factors, not yet fully understood, can also lead to the formation of a two-leaflet aortic valve.
Family Screening and Genetic Counseling
Given the frequent familial clustering of bicuspid aortic valve, screening for the condition is often recommended for first-degree relatives, including parents, siblings, and children of an affected individual. This screening typically involves an echocardiogram, a non-invasive imaging technique that can visualize the heart and its valves. Early detection through screening allows for appropriate monitoring and timely interventions if complications, such as aortic stenosis, regurgitation, or aortic dilation, begin to develop.
Genetic counselors can help assess the risk of inheritance, interpret any genetic test results, and discuss the implications for current and future family planning. Their guidance can empower families with knowledge about the condition’s hereditary patterns and available management strategies. This comprehensive approach helps ensure that at-risk family members receive the necessary evaluations and care to manage BAV and its associated health considerations.