since they rely on related individuals. As a result, epistatic interactions between SNPs, gene environment interactions, and the shared environmental factors of related individuals can all lead to inflated estimates of h2 12,13. We recently showed that by jointly using related and unrelated individuals it is possible to obtain less biased estimates of h2 11. However, the joint fit will still lead to inflated estimates of h2 in the presence of shared environment11, and can not be applied to case-control phenotypes.
