Andreas Chatzittofis

Background Several studies have shown that autoimmune diseases are associated with psychiatric diseases like depression and psychosis. Genetic evidence supports this association. The aim of this study was to investigate if genetic variants predisposing to autoimmune diseases and psychiatric disorders are genetically linked, constructing the common haplotypes. Methods All registered single nucleotide polymorphisms (SNPs) in the Genome‐wide association studies (“GWAS catalog”) having been associated with autoimmune rheumatic and endocrine diseases were investigated for being in linkage disequilibrium with any psychiatric disorders’ associated SNPs. Analysis was performed by the LDtrait and LDhap bioinformatics tools. Results Multiple chromosomal regions have been detected containing rheumatic/endocrine diseases’ predisposing SNPs and psychiatric disorders’ predisposing SNPs. The genetic haplotypes have been constructed for some of these genetic regions. Six of the autoimmune rheumatic and endocrine diseases examined here share a common haplotype with psychiatric diseases at the HLA locus 6p21‐22. Conclusion Our study shows that autoimmune diseases and psychiatric diseases are genetically linked. Genetic haplotypes have been constructed, showing in detail this genetic linkage.