Given the robust evidence linking ALDH1A2 to congenital diaphragmatic hernia, congenital heart disease in general, and tetralogy of Fallot in particular, it is a reasonable hypothesis that the gain in copy of the ALDH1A2 gene in our patient and his mother played a role in the development of pentalogy of Cantrell. The gene discussed is ALDH1A2; the disease is congenital diaphragmatic hernia.