A large portion of phenotypic variability in disease risk for a broad spectrum of disease phenotypes can be explained by regulatory variants, i.e. genetic variants that regulate the expression levels of genes7–10. For example, almost 80% of the chip-based heritability of disease risk for 11 diseases from the WTCCC can be explained by genome variation in DNase I hypersensitivity sites, which are likely to regulate chromatin accessibility and thus transcription11.
