Cardiovascular Genetics

Congenital Heart Disease

Approximately 1 out of 100 babies born has a congenital heart defect (CHD). Congenital heart defects often occur in the setting of multiple congenital anomalies, including abnormal facial features, or in association with limb anomalies, other organ malformations, developmental abnormalities, or growth abnormalities. Most of the known causes of congenital heart disease are sporadic genetic changes, either focal mutations or deletion or addition of segments of DNA.

Genetic factors may be sporadic (identified for the first time in the affected individual) or inherited (passed from parent(s) to child). While a change in the genetic information may be implicated in cardiac disease, that change may have occurred soon after conception affecting all or most cells of the body and therefore affecting the health of that person. Sometimes, however, changes in genetic information are passed from parent to child.



Hypertrophic and Dilated Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a primary disorder of the myocardium that is characterized by unexplained left ventricular hypertrophy (LVH) in a non-dilated ventricle. The clinical spectrum of HCM is diverse, ranging from asymptomatic individuals to those with disabling symptoms of heart failure, exercise intolerance and chest pain. HCM is also associated with an increased risk of sudden cardiac death.

Dilated cardiomyopathy (DCM) is characterized by left ventricle enlargement or dilation (LVE) and reduced systolic function of the heart. It is the most common reason for heart failure and transplant. After acquired causes of DCM have been excluded, DCM is referred to as idiopathic DCM, which includes genetic forms.

The estimated prevalence of idiopathic DCM is estimated to be about 1/2500. About 30 to 50 percent of these individuals are found to have a family history, thus suggesting a genetic etiology. Familial DCM (FDC) is defined by the presence of DCM or unexplained death (before the age of 30) in two or more closely related family members.
 

Long QT Syndrome  

Long QT syndrome (LQTS) is a genetic heart disorder due to malfunction of cardiac ion channels, resulting in 4,000 deaths annually in the United States. LQTS has an estimated prevalence of at least 1 in 3,000 and occurs in all ethnicities. Affected individuals have delayed repolarization manifested by QT prolongation on the electrocardiogram (ECG). There is an increased propensity to syncope, ventricular tachyarrhythmias and sudden cardiac death. Sudden death is the first and final symptom in 10 to 15 percent of fatal LQTS events. LQTS has genetic causes in at least 75 percent of individuals diagnosed with this condition.

The Center for Genetics at Saint Francis offers genetic evaluation, counseling and when appropriate genetic testing for:

  • Congenital heart disease
  • Hypertrophic cardiomyopathy
  • Marfan syndrome/connective tissue disorders
  • Dilated cardiomyopathy
  • Arrhythmogenic right ventricular dysplasia/cardiomyopathy
  • Long QT syndrome and other inherited arrhythmias including Brugada Syndrome and catecholaminergic polymorphic ventricular tachycardia
  • Familial sudden cardiac death
  • Inherited aortic aneurysms

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