CKAP2 and irritable bowel syndrome: Additionally, Eijsbouts et al. [36] explained the familial nature of IBS by discovering six genetic loci for IBS susceptibility (BAG6, CKAP2/TPTE2P3, DOCK9, NCAM1, CADM2, and PHF2/FAM120A) and found that the first four genes are also linked to mood and anxiety disorders, which makes GAD and IBS closely related.