Cross-trait genomic analyses implicate the ITIH3 and ITIH4 locus in the shared genetic architecture of bipolar disorder and obsessive-compulsive disorder

The study used conjunctional FDR analysis on GWAS summary statistics for bipolar disorder (BIP) and obsessive-compulsive disorder (OCD), excluding 23andMe data, to identify variants jointly associated with both disorders. The ITIH3 and ITIH4 locus emerged as a key shared risk region, suggesting common biological pathways that may underlie the frequent co-occurrence of these conditions. Integrative transcriptomic annotation points to potential functional mechanisms involving gene expression regulation. These findings could inform future cross-disorder therapeutic targets and risk prediction models, though replication and functional validation are still needed.