Misestimation of heritability and prediction accuracy of male-pattern baldness

Pirastu et al. 1 perform the largest GWAS to date on male-pattern baldness (MPB), discover 71 loci (of which 30 are new) and draw inference about its heritability and genetic architecture. They report a SNP heritability on the scale of liability ( h l 2 ) of 94%, with 38% of total heritability explained by the 71 loci. From these estimates, they draw strong conclusions about the genetic architecture of MPB. However, the chosen definition of the phenotype and the applied transformation to the unobserved scale of liability have led to a large upwards bias of the estimates of these parameters, as shown here in theory and from data.