Example risk distribution. This distribution has a prevalence of 30% and a heritability of 10%. The mean of the distribution equals the prevalence of the trait. Variance represents the variance of risk due to genetic variation, sometimes called genetic variance, and is proportional to heritability.
Dreyfuss et al. BMC Genomics 2012 13:340 doi:10.1186/1471-2164-13-340