Diegeorg’s syndrome, or congenital absence or hypoplasia of the thymus, is a primary cellular immunodeficiency disease. It is a congenital anomaly caused by the absence or hypoplasia of the thymus and parathyroid glands due to impaired development of the third and fourth pharyngeal sacs during embryonic life. The affected child is often accompanied by other congenital malformations. One of these malformations is left heart outflow tract malformation. The facial features of pediatric Diegeorg’s syndrome include a long face, a bulbous nasal tip and narrow nasal wings, cleft palate, flattened cheekbones, widened eye spacing, slanted eyes, low hanging ears with depressed ear circumference and underdeveloped ear whorl, and a small jaw. The thymus gland (often with parathyroid glands) is underdeveloped or underdeveloped due to some causes (e.g., viral infections, poisoning) that lead to impaired development of the neural crest of the III and IV pharyngeal sacs in early gestation. What are the causes of left heart outflow tract malformation? DiGeorg’s syndrome: DiGeorg’s syndrome (DGS) is associated with chromosome 22q11 defects and should be considered as the sum of the most severe group of clinical disorders, abbreviated by the first letter of each word as “CATCH “22 syndrome, meaning heart defect due to 22q11 deletion ( Cardiac, Abnormal, Thymic, Cleft and Hypocalcemia. Pneumocystis carinii pneumonia (PCP): also known as Pneumocystis carinii pneumonia, or interstitial plasmacytoid pneumonia, is a rare form of pneumonia that occurs mainly in immunocompromised children or in HIV-infected patients. It is the most common infection, accounting for approximately 80% of pulmonary infections in acquired immunodeficiency syndrome, and is the leading cause of death in acquired immunodeficiency syndrome. Pneumonia: is an inflammation of the terminal airways, alveoli and interstitial spaces of the lungs that can be caused by disease organisms, physicochemical factors, immune damage, allergies and drugs. Bacterial pneumonia is the most common form of pneumonia and one of the most common infectious diseases. Before the application of antibiotics, bacterial pneumonia was a great threat to the health of children and the elderly, and the advent and development of antibiotics once led to a significant decrease in the death rate from pneumonia. Autoimmune hemolytic anemia (AIHA): This is an anemia caused by a group of B lymphocytes that are abnormally hyperactive and produce antibodies against their own red blood cells, resulting in increased destruction of red blood cells. Sometimes the destruction of erythrocytes can be compensated by bone marrow erythropoiesis and clinically no anemia occurs, i.e. only autoimmune hemolysis (AIH). In some cases, only anti-auto-erythrocyte antibodies (AI) can be detected without obvious signs of hemolysis. When the body produces both anti-self-erythrocyte antibodies and anti-self-platelet antibodies (even leukocyte antibodies), anemia and thrombocytopenia can occur simultaneously