Atrial septal defect, coronary sinus type is a rare congenital heart defect caused by a malformation of the heart during fetal development. The exact cause of this defect is unknown, but it is believed to be due to a combination of genetic and environmental factors. Possible causes include:
1. Genetic mutations: Certain genetic mutations can cause the coronary sinus to form abnormally, leading to an atrial septal defect.
2. Chromosomal abnormalities: Chromosomal abnormalities, such as Down syndrome, can cause the coronary sinus to form abnormally.
3. Maternal infections: Maternal infections, such as rubella, during pregnancy can cause the coronary sinus to form abnormally.
4. Maternal drug use: Maternal drug use, such as alcohol or tobacco, during pregnancy can cause