Meta-regression analysis suggested this is partly due to interactions with age in the case of IRF4 (Supplementary Table 1)—different nevus subtypes are known to predominate at different ages, with the dermoscopic globular type most common before age 20.32 We suspect sun exposure another important interacting covariate, given large differences in total nevus count by latitude.33,34. Here, IRF4 is linked to nevus.