Conditions Evaluated by the Cardiovascular Genetics Program
Conditions Evaluated by the Cardiovascular Genetics Program
The Cardiovascular Genetics Program provides comprehensive cardiovascular care that includes genetic testing and medical management for all forms of inherited cardiovascular diseases. Genetic testing is used to guide risk assessment and is instrumental in guiding medical decisions. We collaborate and work closely with cardiac, vascular and neurologic specialists to provide the best care to our patients and families.
Inherited cardiac and vascular diseases, as well as related neuromuscular diseases, treated by the Cardiovascular Genetics Program include:
There are four types of cardiomyopathy (chronic diseases of the heart muscle). Each type of cardiomyopathy can be caused by genetic factors, environmental influences or a combination of both. Types of cardiomyopathies include:
Dilated cardiomyopathy (DCM) is characterized by enlargement of the left ventricle chamber of the heart. DCM can be related to coronary artery disease (ischemic) or may arise purely from a defect in the cardiac muscle itself (non-ischemic). DCM usually begins as an enlarged heart and may progress to a heart that has diminished function. As the disease progresses, it can lead to heart failure.
Among patients diagnosed with DCM, over half of those with non-ischemic cardiomyopathy can be attributed to a genetic cause. More than 100 different genes have been associated with DCM and genetic testing is available for many of these genes. In the cases of inherited DCM, there may be a family history of DCM (“enlarged heart”) or heart failure. DCM can also be associated with life threatening irregular heart rhythms (arrhythmias), which can be treated and prevented. Because of the risk of irregular heart rhythms, it is important to identify family members at risk. A family history of sudden death may be an indicator that some family members have DCM.
Hypertrophic cardiomyopathy (HCM) is characterized by a thickening of the heart walls, which interferes with the heart’s ability to pump. HCM can lead to heart failure. Many people with HCM also have irregular heart rhythms (arrhythmia).
Thickening can occur in several places: the wall of the heart’s left ventricle, the wall of the right ventricle or the septum (the wall between the left and right ventricles). In some cases, thickening occurs in more than one location. Nearly 70 percent of HCM is due to genetic causes.
HCM can cause irregular heart rhythms that may be life threatening but can be prevented with device or medical management. A family history of sudden cardiac death or fainting may suggest the presence of HCM.
Arrhythmogenic right ventricular dysplasia/cardiomyopathy
Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by an enlarged right ventricle of the heart, with a change in the consistency of the heart tissue. ARVD/C can also affect the left ventricle with a similar change in the cells that occupy the heart (called “fibrofatty infiltration”). ARVD/C can also be associated with life-threatening irregular heart rhythms such as ventricular tachycardia.
Restrictive cardiomyopathy is characterized by a left ventricle that is normal in size but has diastolic dysfunction. This is an abnormality in how the heart fills with blood because the heart muscle does not relax in a normal manner. Restrictive cardiomyopathy that is infiltrative (amyloidosis, hemochromatosis, glycogen storage disease) may have a genetic component. There are now some specific treatments for people with certain genetic causes.
Duchenne muscular dystrophy and Becker muscular dystrophy
Duchenne muscular dystrophy and Becker muscular dystrophy (DMD/BMD) are progressive muscle diseases that originate from defects in the dystrophin gene. In these conditions, the dystrophin protein is defective in the heart muscle cells. As a result, nearly all individuals with DMD/BMD will develop cardiomyopathy. There are now some specific treatments for people with specific DMD mutations.
Additionally, irregular heart rhythms (arrhythmia) are common among people with DMD/BMD. Arrhythmia can be effectively treated or even prevented with proper intervention.
Limb girdle muscular dystrophy
Limb girdle muscular dystrophy (LGMD) are neuromuscular disorders characterized by progressive skeletal muscle weakness mostly around the muscles of the hips and shoulders. Some LGMD disorders also affect the heart, primarily leading to dilated cardiomyopathy. Early management of LGMD cardiomyopathy can slow progression of the disease, with the goal of preventing heart failure.
Myotonic dystrophy is a degenerative muscle disease caused by an expansion of one of two genes. It results in muscle myotonia, or the inability of the muscles to relax (such as difficulty relaxing a grip). Other organ systems can be involved such as the heart, resulting in irregular heart rhythms. Irregular heart rhythms can be effectively treated or prevented with proper intervention including medications and/or devices.
Friedreich ataxia (FA) is an inherited neuromuscular disorder associated with unsteady gait, weakness and scoliosis. FA is often associated with hypertrophic cardiomyopathy and risk for irregular heart rhythms.
Marfan syndrome is a connective tissue disorder that can affect the heart valves and the aorta. Marfan syndrome is caused by mutations in the fibrillin 1 gene. These mutations can lead to abnormalities of the skeleton and problems involving the heart: aortic valve insufficiency, mitral valve insufficiency (“mitral valve prolapse”) or atrial fibrillation. People with Marfan syndrome are also at risk for an enlarged aorta, which can lead to aneurysm and life-threatening rupture. Early diagnosis and medical management can slow the development of heart issues and aortic enlargement.
Inherited aneurysm syndromes
Inherited aneurysm syndromes involve aneurysms (outpouchings or bulges of the blood vessels) that can develop as part of Marfan syndrome or can be independent of Marfan syndrome. Aneurysms can run in families. Early screening and treatment can be life saving.
Long QT syndrome
Long QT syndrome can be seen as an abnormality on the electrocardiogram (ECG). This syndrome can be associated with irregular heart rhythms, fainting or sudden cardiac death. Long QT syndrome runs in families and can be diagnosed by genetic testing and EKG. Early diagnosis and treatment can be life saving.
Inherited arrhythmia syndromes
Inherited arrhythmia syndromes include irregular heart rhythms such as atrial fibrillation, atrial flutter, supraventricular tachycardias that may run in families. Early diagnosis and intervention can help prevent more serious problems.
Inherited lipid disorders
Inherited lipid disorders are a constellation of disorders characterized by elevated levels of lipids circulating in the blood. Elevation of certain blood lipids can lead to early onset of atherosclerosis (“hardening of the arteries”) from plaque buildup and vascular disease. Some examples of these inherited lipid disorders are hypercholesterolemia and early-onset coronary artery disease. There are many effective treatments for inherited hypercholesterolemia.
Inherited valve disorder
Congenital heart defects
Congenital heart defects are present at birth. Adults born with congenital heart defects may require lifelong cardiovascular management of their heart defect, even if the defect was repaired surgically during childhood. Some congenital heart defects are caused by gene mutations and, therefore, may present a risk to other relatives including children.
Sudden cardiac death
Sudden cardiac death is defined as a sudden, unexpected death caused by loss of heart function and raises suspicion for an inherited form of cardiovascular disease. The Cardiovascular Genetics Program works closely with families to investigate the cause of sudden death by reviewing medical records. The Cardiovascular Genetics Program can provide a risk assessment based on a family’s medical history.