Congenital unguarded mitral orifice (CUMO) is a rare congenital heart defect in which the mitral valve does not close properly, allowing blood to flow backward from the left ventricle to the left atrium. The exact cause of CUMO 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 CUMO, such as mutations in the genes that control the development of the heart.
2. Environmental factors: Exposure to certain environmental toxins, such as alcohol, drugs, and certain medications, can increase the risk of CUMO.
3. Infections: Certain infections, such as rubella, can increase the risk of CUMO.
4. Other conditions: Certain