GRIN2A and Behcet disease: The strongest evidence for association was for duplications at ATF7IP2. GRIN2A, a glutamate receptor, lies downstream of ATF7IP2, and although less significantly associated with BD, functionally it is the better candidate, as glutamate signalling pathways are thought to be involved in genetic predisposition to BD.35 In addition, GRIN2A is associated with SZ, meeting genome-wide significance.36 At the gene CGNL1 (cingulin-like 1), there is overlap with our current BD data and SZ.