Chen F, et al. - Researchers used Pancreatic Cancer Case-Control Consortium (PanC4) genome-wide association study (GWAS) data, to estimate overall heritability of pancreatic cancer and partition the heritability according to variant frequencies and functional annotations. They performed analysis, using the genome-based restricted maximum likelihood method, on data from 3,568 pancreatic cancer cases and 3,363 controls of European Ancestry. They found intronic variants were responsible for most of the estimated heritability (12.4%) among the functional groups (intronic, intergenic, coding, and regulatory variants). They also noted that 4.1% of the total phenotypic variation of pancreatic cancer was explained by previously discovered GWAS loci. The estimated overall heritability was 21.2%, which was higher than previous studies, but possibly still be downwardly biased because of the inherent limitation that the application of these commonly used methods to imputed GWAS data does not reveal the contribution of rare variants in genes with a substantive overall influence on disease.