Genetic variants on 3q21 and in the Sp8 transcription factor gene (SP8) as susceptibility loci for psychotic disorders: a genetic association study

PLoS One. 2013 Aug 13;8(8):e70964. doi: 10.1371/journal.pone.0070964. eCollection 2013.

Abstract

Background: Recent genome-wide association studies (GWASs) investigating bipolar disorder (BD) have detected a number of susceptibility genes. These studies have also provided novel insight into shared genetic components between BD and schizophrenia (SCZ), two major psychotic disorders. To examine the replication of the risk variants for BD and the pleiotropic effect of the variants associated with BD, we conducted a genetic association study of single nucleotide polymorphisms (SNPs) that were selected based upon previous BD GWASs, which targeted psychotic disorders (BD and SCZ) in the Japanese population.

Methods: Forty-eight SNPs were selected based upon previous GWASs. A two-stage analysis was conducted using first-set screening (for all SNPs: BD = 1,012, SCZ = 1,032 and control = 993) and second-set replication samples (for significant SNPs in the screening analysis: BD = 821, SCZ = 1,808 and control = 2,149). We assessed allelic association between BD, SCZ, psychosis (BD+SCZ) and the SNPs selected for the analysis.

Results: Eight SNPs revealed nominal association signals for all comparisons (Puncorrected<0.05). Among these SNPs, the top two SNPs (associated with psychosis: Pcorrected = 0.048 and 0.037 for rs2251219 and rs2709722, respectively) were further assessed in the second-set samples, and we replicated the signals from the initial screening analysis (associated with psychosis: Pcorrected = 0.0070 and 0.033 for rs2251219 and rs2709722, respectively). The meta-analysis between the current and previous GWAS results showed that rs2251219 in Polybromo1 (PBRM1) was significant on genome-wide association level (P = 5×10(-8)) only for BD (P = 9.4×10(-9)) and psychosis (P = 2.0×10(-10)). Although the association of rs2709722 in Sp8 transcription factor (SP8) was suggestive in the Asian population (P = 2.1×10(-7) for psychosis), this signal weakened when the samples size was increased by including data from a Caucasian population (P = 4.3×10(-3)).

Conclusions: We found 3p21.1 (including PBRM1, strong linkage disequilibrium made it difficult to pinpoint the risk genes) and SP8 as risk loci for BD, SCZ and psychosis. Further replication studies will be required for conclusive results.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Asian People / genetics
  • Bipolar Disorder / genetics
  • Case-Control Studies
  • Chromosomes, Human, Pair 3*
  • DNA-Binding Proteins / genetics*
  • Female
  • Genetic Association Studies
  • Genetic Predisposition to Disease*
  • Genome-Wide Association Study
  • Humans
  • Japan
  • Male
  • Meta-Analysis as Topic
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • Psychotic Disorders / genetics*
  • Quantitative Trait Loci*
  • Schizophrenia / genetics
  • Transcription Factors / genetics*

Substances

  • DNA-Binding Proteins
  • Sp8 protein, human
  • Transcription Factors

Grants and funding

This work was supported by research grants from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, the Ministry of Health, Labor and Welfare of Japan, the Academic Frontier Project for Private Universities, Comparative Cognitive Science Institutes, the Uehara Memorial Foundation, the SEISHIN Medical Research Foundation, the Takeda Science Foundation and the Strategic Research Program for Brain Sciences of the MEXT of Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.