This document discusses the relationship between consanguinity (marriage between close biological relatives) and congenital heart disease (CHD). It makes several key points: 1) Consanguineous unions increase the risk of recessive diseases like CHD being expressed. Several studies found associations between consanguinity and more severe forms of CHD. 2) However, determining the exact genetic contribution is difficult since other factors like environment, epigenetics, and sociodemographics also influence CHD risk. 3) Around 10% of the world's population engages in consanguineous marriages, particularly in parts of Asia, Africa, and migrant communities from those regions. First cousin marriages are most common