DiGeorge Syndrome is a genetic condition present from birth, stemming from a small missing segment on chromosome 22, specifically at location 22q11.2. This genetic change can affect the development of several body systems, leading to a range of health issues. Congenital heart defects are a common and significant concern, affecting the majority of individuals diagnosed with the syndrome. This article explores the common heart defects associated with DiGeorge Syndrome, along with their recognition, diagnosis, treatment, and long-term outlook.
Common Heart Defects
Individuals with DiGeorge Syndrome experience heart defects that arise during fetal development. One such defect is truncus arteriosus, where a single large blood vessel emerges from the heart instead of the usual two separate arteries, the aorta and pulmonary artery. This single vessel includes a hole in the wall between the heart’s lower chambers, known as a ventricular septal defect, causing oxygen-rich and oxygen-poor blood to mix. The mixed blood then flows to both the lungs and the body, leading to insufficient oxygen delivery.
Another cardiac anomaly is interrupted aortic arch, characterized by a gap in the aorta, the body’s main artery. This interruption prevents oxygen-rich blood from reaching the lower parts of the body. Most infants with this condition also present with a ventricular septal defect.
Tetralogy of Fallot represents a combination of four heart abnormalities: a ventricular septal defect, a narrowing of the pulmonary valve or artery (pulmonary stenosis), the aorta positioned directly over the ventricular septal defect (overriding aorta), and a thickening of the right ventricle muscle (right ventricular hypertrophy). These combined defects disrupt normal blood flow, resulting in low oxygen levels in the blood and a bluish discoloration of the skin. Approximately 15% of individuals with Tetralogy of Fallot also have DiGeorge Syndrome.
Ventricular septal defects (VSDs) are frequently observed in DiGeorge Syndrome. These defects allow oxygen-rich blood from the left ventricle to flow into the right ventricle and back to the lungs. VSDs can occur as isolated defects or as part of more complex conditions like Tetralogy of Fallot.
Recognizing and Diagnosing Heart Defects
Heart defects associated with DiGeorge Syndrome can be identified before birth through prenatal diagnostic methods. A fetal echocardiogram, an ultrasound of the baby’s heart, can detect structural abnormalities. Prenatal ultrasound tests and amniocentesis can also suggest DiGeorge Syndrome and its related heart conditions.
Following birth, diagnosis involves a physical examination where medical professionals observe signs. These include cyanosis, a bluish tint to the skin caused by poor blood circulation and low oxygen levels, or the presence of a heart murmur. Infants may also exhibit difficulty feeding, poor weight gain, or breathing difficulties. Genetic testing for the 22q11.2 deletion confirms the diagnosis of DiGeorge Syndrome. Further cardiac evaluation includes a postnatal echocardiogram to visualize heart structures, a chest X-ray to assess heart size and lung blood flow, and an electrocardiogram (ECG) to evaluate the heart’s electrical activity.
Treatment and Management of Heart Defects
Treatment for heart defects in DiGeorge Syndrome involves medical management and surgical interventions. Medications can be prescribed to manage symptoms, such as improving heart function or controlling blood pressure. These aim to stabilize the child’s condition before or alongside surgical repair.
Surgical correction is necessary for these heart defects. For truncus arteriosus, surgery involves separating the single vessel into two distinct arteries (aorta and pulmonary artery) and closing the associated ventricular septal defect. For Tetralogy of Fallot, surgery occurs within the first six months of life, aiming to widen the narrowed pulmonary tract and close the ventricular septal defect with a patch.
The timing of surgery is influenced by the defect’s severity and the child’s overall health, with interventions needed soon after birth to address issues with circulation, breathing, or growth. The goals of these treatments are to ensure efficient blood circulation and to improve the heart’s ability to pump oxygenated blood throughout the body.
Long-Term Outlook for Heart Health
Individuals with DiGeorge Syndrome and associated heart defects require ongoing specialized care. Regular follow-up appointments with a cardiologist are important to monitor heart function and detect potential long-term complications. This oversight helps manage the challenges posed by these congenital conditions.
Despite successful initial treatments, some individuals may face long-term complications, such as arrhythmias (irregular heartbeats), heart failure, or the need for re-operations as they grow. Conduits and patches used in initial surgeries may require replacement over time due to growth or wear. While mortality rates can be higher in infancy due to the severity of heart defects or immune deficiencies, advancements in medical and surgical care have significantly improved outcomes. With comprehensive medical management, many individuals with DiGeorge Syndrome and heart defects can lead fulfilling lives, emphasizing the importance of lifelong cardiac care.