Genome-wide Significant Locus for Research Diagnostic Criteria Schizoaffective Disorder Bipolar Type

Studies have suggested that Research Diagnostic Criteria for Schizoaffective
Disorder Bipolar type (RDC-SABP) might identify a more genetically homogenous
subgroup of bipolar disorder. Aiming to identify loci associated with RDC-SABP, we
have performed a replication study using independentRDC-SABP cases (n = 144) and
controls (n = 6,559), focusing on the 10 loci that reached a p-value <10−5 for RDCSABP
in the Wellcome Trust Case Control Consortium (WTCCC) bipolar disorder
sample. Combining theWTCCC and replication datasets by meta-analysis (combined
RDC-SABP, n = 423, controls, n = 9,494), we observed genome-wide significant
association at one SNP, rs2352974, located within the intron of the gene TRAIP on
chromosome 3p21.31 (p-value, 4.37 × 10−8). This locus did not reach genome-wide
significance in bipolar disorder or schizophrenia large Psychiatric Genomic
Consortium datasets, suggesting that it may represent a relatively specific genetic
risk for the bipolar subtype of schizoaffective disorder.