COL9A3 and post-traumatic stress disorder: When we examined all of the probes in each of the previously implicated genes (Additional file 1: Table S6), 3 genes showed associations with PTSD that withstood corrections for the number of probes in the respective gene: (a) AHRR (coefficient = − 0.13, p = 9.16 × 10-6, padj = 0.00082); (b) CLEC9A, where the most significant association was with cg02930518 (coefficient = 0.089, p = 0.0067, padj = 0.040); and (c) COL9A3, where the most significant locus was cg08021508 (coefficient = − 0.16, p = 0.00066, padj = 0.025).