Levo-transposition of the great arteries causes


 * Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [mailto:psingh@perfuse.org]; ; Keri Shafer, M.D. [mailto:kshafer@bidmc.harvard.edu]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [mailto:kfeeney@perfuse.org]

Overview
The cause of most congenital heart defects is unknown.

Causes
The cause of most congenital heart defects is unknown. Factors in the mother that may increase the risk of this condition include:
 * Age over 40
 * Alcoholism
 * Diabetes
 * Prenatal nutrition
 * Rubella or other viral illness during pregnancy
 * Generally, TGA is not known to be associated with any specific single gene defect, but some studies have shown possible genetic association in some cases of TGA, involving deletions of chromosome 22q11.