raw data via mega-analysis (38), we were limited in our ability to conduct additional post-hoc analyses such as GPRS and GREML that require the use of raw GWAS data. Reassuringly, results obtained by applying LD score regression to summary statistics from the total meta-analysis sample were consistent with those using raw data from select individual samples. Fourth, the results apply only to subjects of European-ancestry and might not generalize to individuals of other genetic and cultural backgrounds. Finally, we combined all data available at the time of this study into a single meta-analysis rather than divide into discovery and replication samples. This was necessary due to the large sample sizes required to detect small effects of genes involved in complex traits like ADs. Internal cross-validation supported the robustness of our results but do not substitute for replication in well-powered, independent samples. At this time, we are unaware of other large data sets that could be used for replication of our results.
