In the case-control sample, no SNPs exceeded the genome-wide threshold for significance (Table 1, Figure 2). Nine OCD-associated SNPs had p-values<1 × 10-5 (Table 1). The lowest two p-values were for SNPs rs11081062 (p=2.49×10-6) and rs11663827 (p=3.44×10-6), located at chromosome 18 within an intron of DLGAP1 (Figure 3). DLGAP1 (also known as SAPAP1) encodes the discs, large (Drosophila) homolog-associated protein a member of the neuronal postsynaptic density complex. The third lowest p-value was for the SNP rs26728 (p=4.75×10-6), located within an intron of EFNA5, encoding Ephrin-A5 (Supplementary Figure S12). Ephrins are important for development of the neocortex through regulation of axonal inhibition or repulsion,58 and EFNA5 was also among top hits in an Alzheimer's disease GWAS.59 The fourth lowest p-value=5.40×10-6, was for rs4868342, lying within an intron of HMP19, encoding the brain-specific HMP19 protein (Supplementary Figure S12), which is expressed in the Golgi complex.60 The fifth lowest p-value=5.81×10-6, was for rs297941, which is located approximately 21 kb 5′ to the gene encoding FAIM2 (also known as LFG) and about 25 kb from a cluster of genes encoding a group of aquaporins (AQP5, AQP6, AQP2), and lies within a putative coding region of mRNA BC034605, isolated from testis (Supplementary Figure S12).
