Harnessing expression data to identify novel candidate genes in polycystic ovary syndrome

PLoS One. 2011;6(5):e20120. doi: 10.1371/journal.pone.0020120. Epub 2011 May 17.

Abstract

Novel pathways in polycystic ovary syndrome (PCOS) are being identified in gene expression studies in PCOS tissues; such pathways may contain key genes in disease etiology. Previous expression studies identified both dickkopf homolog 1 (DKK1) and DnaJ (Hsp40) homolog, subfamily B, member 1 (DNAJB1) as differentially expressed in PCOS tissue, implicating them as candidates for PCOS susceptibility. To test this, we genotyped a discovery cohort of 335 PCOS cases and 198 healthy controls for three DKK1 single nucleotide polymorphisms (SNPs) and four DNAJB1 SNPs and a replication cohort of 396 PCOS cases and 306 healthy controls for 1 DKK1 SNP and 1 DNAJB1 SNP. SNPs and haplotypes were determined and tested for association with PCOS and component phenotypes. We found that no single nucleotide polymorphisms were associated with PCOS risk; however, the major allele of rs1569198 from DKK1 was associated with increased total testosterone (discovery cohort P = 0.0035) and dehydroepiandrosterone sulfate (replication cohort P = 0.05). Minor allele carriers at rs3962158 from DNAJB1 had increased fasting insulin (discovery cohort P = 0.003), increased HOMA-IR (discovery cohort P = 0.006; replication cohort P = 0.036), and increased HOMA-%B (discovery cohort P = 0.004). Carriers of haplotype 2 at DNAJB1 also had increased fasting insulin, HOMA-IR, and HOMA-%B. These findings suggest that genetic variation in DKK1 and DNAJB1 may have a role in the hyperandrogenic and metabolic dysfunction of PCOS, respectively. Our results also demonstrate the utility of gene expression data as a source of novel candidate genes in PCOS, a complex and still incompletely defined disease, for which alternative methods of gene identification are needed.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Case-Control Studies
  • Cohort Studies
  • Databases, Genetic*
  • Female
  • Gene Expression Regulation*
  • Genetic Association Studies / methods*
  • HSP40 Heat-Shock Proteins / genetics
  • Haplotypes / genetics
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Linkage Disequilibrium / genetics
  • Polycystic Ovary Syndrome / genetics*
  • Polymorphism, Single Nucleotide / genetics
  • Reproducibility of Results

Substances

  • DKK1 protein, human
  • DNAJB1 protein, human
  • HSP40 Heat-Shock Proteins
  • Intercellular Signaling Peptides and Proteins