What heart conditions may benefit from genetic testing?
Below is information about commonly encountered cardiovascular conditions that may benefit from genetic testing and a genomics consultation.
Amyloidoses are a group of conditions characterized by the buildup of abnormal proteins in the heart and other organs. Cardiac amyloidosis can cause cardiac function to deteriorate and possibly fail as the heart becomes stiffer. There are several recognized forms of amyloidosis. Genetic changes in the TTR gene can cause a type of amyloidosis called familial transthyretin amyloidosis, which can be inherited from parent to child.
Brugada syndrome is a hereditary cardiac condition characterized by ventricular arrhythmia, or irregular heartbeats of the lower chambers of the heart. This arrhythmia can cause fainting, palpitations and sudden death. Brugada syndrome can run through families, with the children of a person with Brugada syndrome having a 50/50 chance of inheriting the same condition. Genetic changes in a gene called “SCN5A” can cause Brugada syndrome.
Learn more about Brugada syndrome
Dilated cardiomyopathy (DCM)
Dilated Cardiomyopathy (DCM) refers to an enlarged cavity of the heart that compromises the heart’s ability to pump and can cause heart failure, arrhythmia and/or thromboembolism. DCM is the most common form of cardiomyopathy and can have several causes. In younger patients and in family with multiple individuals with DCM, the cause may be a genetic change that can be passed down through generations. Over 30 genes have been associated with familial dilated cardiomyopathy. A genetic testing panel with many genes or a smaller test may be good for you.
Learn more about dilated (nonischemic) cardiomyopathy
Ehlers-Danlos syndrome (EDS)
Ehlers-Danlos syndrome (EDS) often referred to as “EDS” is a collection of heritable connective tissue disorders. Changes or mutations in connective tissue cause the signs and symptoms of EDS, which can vary from mildly loose joints to life-threatening vascular complications. The different types of EDS are distinguished by their respective signs and symptoms, underlying genetic causes, and patterns of inheritance. Mutations in more than a dozen genes have been found to cause EDS but there are still many genetic changes that have yet to be identified.
Familial hypercholesterolemia is a genetic condition characterized by very high levels of cholesterol in the blood. Cholesterol is a waxy, fat-like substance that is produced in the body and obtained from foods. While the body needs this substance, too much cholesterol increases a person's risk of developing coronary artery disease. Inherited forms of hypercholesterolemia not only significantly increase the risk of early coronary artery disease but it can also cause additional health problems related to the buildup of excess cholesterol in other tissues. Three different genes are known to cause 60-80% of cases of familial hypercholesterolemia.
Hypertrophic cardiomyopathy (HCM)
Hypertrophic cardiomyopathy (HCM) is an inherited disease of the heart muscle that affects an estimated 1 in 500 people worldwide. It is the most common genetic heart disease in the United States. The most consistent feature in HCM is thickening of the left ventricle which can lead to obstructing blood flow to the rest of the body. HCM also involves disarray or disorganization of the heart muscle cells which can lead to an irregular heart rhythm (called arrhythmias). HCM can affect men and women of all ages, and symptoms can appear in childhood or adulthood. Mutations in one of several genes can cause HCM and there is often variability in presentation amongst family members.
Learn more about hypertrophic cardiomyopathy
Loeys Dietz syndrome
Loeys Dietz Syndrome is a genetic disorder involving connective tissue. Connective tissue provides strength and flexibility to structures such as bones, muscles, and blood vessels. There are four different types of Loeys-Dietz syndrome which are distinguished by their different genetic causes. Regardless of the type, signs and symptoms of Loeys-Dietz syndrome can become apparent anytime in childhood or adulthood, and the severity is variable. Common signs include wide-set eyes, aortic or arterial aneurysm or dissection and a variety of skeletal, skin and digestive features.
Learn more about Loeys Dietz syndrome: Loeys Dietz Syndrome Foundation / NIH website
Long QT syndrome (LQTS)
Long QT syndrome (LQTS) is a disease that you can inherit or that can be acquired. It affects the bottom pumping chambers of the heart (ventricles) by impacting the highly coordinated ion channels regulating the flow of electricity needed to generate normal heartbeats. In LQTS, a problem in the ion channels leads to electrical instability. This can cause a very rapid and dangerous heart rhythm that can lead to fainting or sudden death. The name long QT stems from the abnormal wave length read on the electrocardiogram (ECG) machine which is used to evaluate an individual’s heartbeat. While cardiac events may occur from infancy through middle age, they are most common from the pre-teen years through the 20s. Some types of LQTS are associated with a phenotype extending beyond cardiac arrhythmia. There are different types of LQTS caused by mutations in different genes.
Learn more about Long QT syndrome (LQTS): NCBI / StayWell Library
Marfan syndrome is a connective tissue disorder that affects approximately 1 in every 5,000 people worldwide. Marfan syndrome affects multiple parts of the body, but the cardiac complications are typically the most serious. People with this condition often have mitral valve prolapse, arrhythmia, dilation of the aorta, or other cardiac complications that can be life-threatening. Genetic changes in the FBN1 gene cause Marfan syndrome, which can be inherited from parent to child.
Learn more about Marfan syndrome
Sudden cardiac arrest
Sudden cardiac arrest occurs when an acute cardiac event causes a person to die within minutes. Sometimes, a specific cause is identified and other times, the death remains unexplained and unrecognized as a cardiac arrest. There are several hereditary cardiac conditions that can cause sudden cardiac arrest, such as cardiomyopathies or arrhythmias. Families with young and/or multiple individuals who had a sudden unexplained death or sudden cardiac arrest (not otherwise specified) may benefit from genetic testing to predict other relative’s risk of sudden cardiac arrest.
For more information about our Cardiovascular Genomics Center or to schedule an appointment please call 1-855-5CV-GENE or email CVGENOMICS@inova.org
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