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.