A Novel Relationship for Schizophrenia, Bipolar and Major Depressive Disorder Part 6: A Hint from Chromosome 6 High Density Association Screen.

BACKGROUND: Convergent evidence from genetics, symptomatology and psychopharmacology imply that there are intrinsic connections between schizophrenia (SCZ), bipolar disorder (BPD) and major depressive disorder (MDD), for example, any two or even three of these disorders could co-exist in some families.

OBJECTIVE: To screen out the susceptibility genes on chromosome 6 comprehensively for SCZ, BPD and MDD in a relative homogenous population in China.

METHOD: A total of 56.400 single nucleotide polymorphism (SNPs) on chromosome 6 were genotyped by Affymetrix Genome-Wide Human SNP array 6.0 on 119 SCZ, 253 BPD (type- I), 177 MDD patients and 1000 controls.

RESULTS: Associated SNP loci on chromosome 6 were comprehensively revealed and outstanding susceptibility genes were identified including JARID2 (Homo sapiens jumonji, AT rich interactive domain 2) which plays an essential role in embryonic development and neural tube fusion process. Unexpectedly, flanking genes for all associated SNPs were replicated in an enlarged cohort of 986 SCZ patients.

CONCLUSION: Considering all evidence, our results imply that both of bipolar disorder and major depressive disorder are subtypes of schizophrenia. Furthermore, JARID2 is an important psychosis gene in this population.