A Novel Relationship for Schizophrenia, Bipolar, and Major Depressive Disorder. Part 8: a Hint from Chromosome 8 High Density Association Screen.

Convergent evidence from genetics, symptomatology, and psychopharmacology implies 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. A total of 48,753 single nucleotide polymorphisms (SNPs) on chromosome 8 were genotyped by Affymetrix Genome-Wide Human SNP array 6.0 on 119 SCZ, 253 BPD (type I), 177 MDD patients, and 1000 controls. Associated SNP loci were comprehensively revealed, and outstanding susceptibility genes were identified including CSMD1, NRG1, PXDNL, SGCZ, and TMEM66. Unexpectedly, flanking genes for up to 95.9 % of the associated SNPs were replicated (P ≤ 9.9E-8) in the enlarged cohort of 986 SCZ patients. Considering convergent evidence, our results implicate that bipolar disorder and major depressive disorder might be subtypes of schizophrenia.