We attempted to determine, at each locus, whether we could identify a potentially causal variant. We performed these analyses using European ancestry subjects alone, and in all subjects with genome-wide data, and excluded variants that were not present in at least 80% of the full sample. We assumed a single causal variant at each locus, examined a +/− 250kb region around the top variant, and calculated approximate Bayes factors using the method of Wakefield68 to determine the 95% credible set. While specific trans-ethnic mapping approaches69,70 can significantly assist in identifying causal loci, we found that the number of non-European samples in our study were likely insufficient to leverage these methods.
