Approximately 95% of patients are standard trisomy 21, 46, XX, +21 or 46, XY, +21. The overall prevalence of Down syndrome has been estimated to be 1/700 live births, 2) although it is highly dependent on maternal age and has decreased significantly as a result of routine prenatal testing.Ĭonventional karyotyping is indicated in all Down patients to confirm the diagnosis. The following are discussed: Down syndrome, Turner syndrome, 22q11 deletion syndrome, Williams syndrome, and Noonan syndrome.ĭown syndrome is a chromosomal abnormality caused by the presence of a third copy of chromosome 21 and is manifested by characteristic facial dysmorphism, various congenital anomalies, including cardiac or gastrointestinal defects, variable degrees of intellectual disability, hypotonia, and joint laxity. Here, common genetic syndromes associated with various types of congenital heart disease are introduced with a brief review of their respective genetic backgrounds. Understanding genetic etiology in a certain patient with both congenital heart disease and other anomalies can help clinicians to effectively plan a patient's surgical and medical management and their follow-up. 1) Recent advances in molecular genetic techniques have found evidence of the role of genetic factors in the development of congenital heart disease ( Table 1). Approximately 30% of congenital heart disease is thought to be related to genetic syndromes accompanied by extra-cardiac anomalies. Congenital heart disease is a multifactorial disorder associated with both genetic and environmental influences. In addition, multidisciplinary approaches and care for the combined extra-cardiac anomalies may help to reduce mortality and morbidity accompanied with congenital heart disease.Ĭongenital heart disease is the leading cause of birth defects, and is an important cause of morbidity and mortality during infancy and childhood. Therefore, risk management based on an accurate genetic diagnosis is necessary in order to effectively plan the surgical and medical management and follow-up for these patients. Although surgical techniques and perioperative care have improved substantially, patients with genetic syndromes may be at an increased risk of death or major complications associated with surgery. This review introduces common genetic syndromes showing various types of congenital heart disease, including Down syndrome, Turner syndrome, 22q11 deletion syndrome, Williams syndrome, and Noonan syndrome. Congenital heart disease is the leading cause of birth defects, and is an important cause of morbidity and mortality during infancy and childhood. Congenital heart disease is frequently accompanied by genetic syndromes showing both cardiac and extra-cardiac anomalies. Many kinds of genetic tests are commercially available, and more are currently under development. However, in this case the Ventricular Septal Defect (VSD) allows mixing of oxygen-rich blood from the left ventricle into the right ventricle, which pumps blood into the pulmonary artery.Recent research has demonstrated that genetic alterations or variations contribute considerably to the development of congenital heart disease. The pulmonary artery normally carries oxygen-poor blood to the lungs, so it might seem that blood entering the lower aorta from this vessel (through the PDA) would not carry enough oxygen to the lower body.
(The Patent Ductus Arteriosus is a feature of the circulatory system that usually closes soon after birth.) However, some blood does enter the lower part of the aorta because of a small vessel, known as the Patent Ductus Arteriosus (PDA), that connects the lower part of the aorta with the pulmonary artery. Second, there is a hole, called a Ventricular Septal Defect (VSD in diagram), in the muscle wall (septum) that separates the two ventricles, or pumping chambers of the heart.īecause the aorta is interrupted and cannot carry blood from the left ventricle to the lower body as in a normal heart, it might seem that the child with this anomaly could not survive. The aortic arch is the part of the aorta (the major vessel that carries oxygen-rich blood from the heart to the body's tissues) that curves directly above the heart and begins the descent to the lower body. First, the Aortic Arch does not form a complete tube and is divided, or "interrupted" (see upper arrow in diagram). This rare genetic disorder involves two defects.
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