Congenital heart disease, defined as a gross structural abnormality of the heart, is the most common type of human birth defect, occurring in ∼9 per 1000 live births and at a significantly greater incidence in miscarriage and still births. The complexity in understanding the etiology of congenital heart diseases is heightened by disease variability influenced by genetic, epigenetic and/or environmental modifiers. Environmental factors are known to contribute to CHDs, but the pathophysiology and associated gene-environment interactions are not well-known. Well-recognized nongenetic causes of CHDs include environmental teratogens, such as excess maternal exposures to Vitamin A and its retinoid derivatives (e.g. isotretinoin). Pregestational maternal diabetes is a well-established adverse environment for embryonic development, due to fetal exposure to elevated blood glucose levels. It is associated with a 5X increase in CHD incidence. The molecular mechanisms underlying these lethal effects are not well understood. Dr Sonia Stefanovic is currently studying the consequence of deregulated Vitamin A signaling on mouse embryos genetically predisposed to heart defects and the impact of maternal diabetes on CHDs, projects being supported by H2020-MSCA-IF-2014, ERA-CVD-2019 and ANR-JCJC-2020.