For example, haploinsufficiency for a broad range of chromatin regulators is one of the most significant contributors to human congenital heart disease (Zaidi et al., 2013), and dose regulation of H3K27me3 levels by altering levels of EED and JMJD3 have been shown to regulate the ratio of β-cell subtypes in the pancreas (Dror et al., 2023). The gene discussed is EED; the disease is congenital heart disease.