The association between each SNP and the binary trait was estimated in a multivariate logistic regression framework under a log-additive genetic model. We used PLINK for the SNP-trait association test in the region of the linkage peak in the SAGE sample, with sex, age and the top 10 PCs as covariates. For the replication analysis and joint data analysis stages for rs17664708, we included sex, age, and global or local ancestry estimates as covariates where appropriate, and analysis was performed using the R package “SNPassoc” (48).
