Does Tetralogy of Fallot involve chromosomal abnormalities?

Written by Chen Guang Yin

Cardiology

Updated on December 02, 2024

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Tetralogy of Fallot is primarily a developmental disorder, generally unrelated to chromosomes, with no chromosomal abnormalities. The cause of the disease is still not very clear. If pregnant again and giving birth again, it generally does not recur. Therefore, couples undergoing chromosomal testing before pregnancy is a common practice. It is generally believed that the four malformations in Tetralogy of Fallot occur due to viral infections acquired by the fetus during pregnancy, the mother consuming alcohol, or the use of certain medications during pregnancy. Currently, these are considered related factors, and so far, no abnormalities have been found related to genetics or chromosomes.

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Written by Hu Qi Feng

Pediatrics

38sec

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The reason for squatting in Tetralogy of Fallot

The reason for squatting is that when squatting, the lower limbs are bent, which reduces the amount of blood returning to the heart through the veins, thereby reducing the load on the heart. At the same time, the arteries in the lower limbs are compressed, which increases the resistance in the systemic circulation and reduces the right-to-left shunt volume, allowing temporary relief from hypoxia symptoms. Babies who cannot walk often like to be held by adults in a position that bends the lower limbs to reduce the amount of blood returning to the heart. This frequently occurs during walking and playing, often characterized by brief periods of squatting.

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Written by Hu Qi Feng

Pediatrics

1min 12sec

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Tetralogy of Fallot Common Symptoms

The clinical manifestations of Tetralogy of Fallot include, firstly, cyanosis as the primary clinical symptom. The degree and onset of cyanosis are related to the severity of pulmonary stenosis, and it often appears in areas with abundant capillaries such as lips, fingers, toes, nail beds, and bulbar conjunctiva. Secondly, squatting symptoms are common among children; they often spontaneously squat for a while during walking or playing. Squatting, with the legs bent, reduces the venous return and thus decreases the load on the heart, temporarily relieving symptoms of hypoxia by reducing the right-to-left shunt. Thirdly, clubbing occurs due to long-term hypoxic conditions, which can cause capillary dilation and proliferation in the fingers and toes, and the local soft tissues and bones also grow and enlarge; fourthly, paroxysmal hypoxic attacks, which are most common in infants, can be triggered by breastfeeding, crying, emotional excitement, or anemia. These attacks suddenly occur and can lead to severe symptoms including difficulty breathing, fainting, convulsions, and even death.

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Written by Yan Xin Liang

Pediatrics

1min 20sec

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Is Tetralogy of Fallot serious?

Tetralogy of Fallot is the most common cyanotic congenital heart disease in children, accounting for about 10% of congenital heart diseases. It is a complex type of congenital heart condition, consisting of four defects: a ventricular septal defect, right ventricular outflow tract obstruction, overriding aorta, and right ventricular hypertrophy. Due to these four malformations, children will experience cyanosis, poor exercise tolerance, and may quickly become fussy or emotionally disturbed with physical activity. This can lead to noticeable worsening of dyspnea and cyanosis. They may also exhibit a preference for squatting, as squatting can decrease the return blood volume to the heart, increase systemic vascular resistance, and temporarily relieve hypoxic symptoms. Other symptoms include clubbing, paroxysmal hypoxia attacks which are more common in infants. These attacks can be triggered by crying, emotional excitement, anemia, infections, etc., and suddenly manifest as paroxysmal breathing difficulties. In severe cases, there can be fainting, convulsions, and even death. Therefore, these clinical manifestations are very serious, making this disease a significantly dangerous condition.

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Written by Hu Qi Feng

Pediatrics

1min 10sec

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Tetralogy of Fallot symptoms in infants

Infants with Tetralogy of Fallot often exhibit the following symptoms: First, cyanosis, which is most apparent in areas rich in capillaries such as the lips, fingernail beds, and conjunctiva. Cyanosis tends to worsen gradually during crying, emotional distress, or physical exertion. Second, squatting symptoms; infants who cannot walk often prefer to be held by adults in a flexed position of both lower limbs, reducing venous return and easing the cardiac workload. Older children often exhibit squatting during activities such as walking and playing, frequently squatting down momentarily. Third, infants in a prolonged hypoxic environment may develop clubbing, characterized by the enlargement of the fingertips and toes, with capillary expansion and proliferation, resembling drumsticks. Fourth, episodic hypoxia occurs predominantly in infants, triggered by feeding, crying, or emotional distress, manifesting as episodes of respiratory difficulty, with severe cases leading to sudden fainting or convulsions.

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Written by Hu Qi Feng

Pediatrics

48sec

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Tetralogy of Fallot Clinical Characteristics

Tetralogy of Fallot is the most common cyanotic congenital heart disease in infancy, accounting for about 12% of all congenital heart diseases. It is caused by malformations of four heart structures: 1. right ventricular outflow tract obstruction; 2. ventricular septal defect; 3. overriding aorta; 4. right ventricular hypertrophy. Its clinical manifestations may include cyanosis, squatting symptoms, clubbed fingers, and paroxysmal hypoxia attacks. Physical examinations generally show delayed development, a prominent precordial area, and at the second to fourth rib interspace along the left sternal margin, a grade 2 to 3 rough systolic murmur can be heard.