one of the HLA genes residing in this region, HLA-A, was among the small group of DEGs that remained statistically significant at a genome-wide scale. It should also be pointed out that the most robust GWAS (genome wide association studies) signals in SZ map to the HLA locus [97–99]. Although the physical interaction between 22q11.2 and 6p21 needs to be confirmed and further characterized, our findings suggest that 22q11.2 deletion may affect HLA gene expression through direct long-range contact in trans. In this regard, we should mention that abnormal expression of immune response genes, especially HLA genes in 6p21, has been often suggested to be a common factor underlying neurodevelopmental disorders [96, 100]. It should be noted, however, that HLA proteins have been suggested to have non-immune effects on synaptogenesis [101–105].
