NCAN and Behcet disease: Recent analyses suggested a substantial overlap of genetic risk factors between SZ and BD (Lichtenstein et al., 2009), and genome-wide association studies (GWAS) have revealed multiple genomic loci showing significant associations with both illnesses in European populations (Ruderfer et al., 2014; Bipolar Disorder Schizophrenia Working Group of the Psychiatric Genomics Consortium, 2018), such as loci of CACNA1C, VRK2, TRANK1, ZNF804A, NCAN and the extended MHC region (Ripke et al., 2020; Mullins et al., 2021).