Family-based studies were critical to demonstrating the role of genetic factors in the intergenerational transmission of alcohol use disorder (AUD)1 and provided the empirical foundation for subsequent gene identification efforts ranging from linkage to GWAS2. The conventional understanding is that genetic risk is passed in families from parents to children through allele sharing. Yet, allele sharing represents only one potential mode of transmission of genetic risk in families. Indeed, robust evidence from twin and adoption studies indicate that genetic influences also operate “beyond the skin” to shape the environment3. Thus, in addition to direct allele transmission, parental genotypes may influence children’s outcomes indirectly, via the family environment4. Here we examined two common family adversities, parental divorce and parental relationship discord, as mechanisms through which genetic risk for alcohol problems may be transmitted in families.
