Genes that affect multiple, apparently unrelated, phenotypes (e.g. environmental diseases, multifactorial traits) are called pleiotropic genes, and the phenomenon is termed “pleiotropy.” Authors in the attached main article analyze and identify hundreds of loci that are associated with multiple traits or diseases––by comparing genome-wide association (GWA) data for 42 complex traits. The study uses the power of GWAS to provide evidence that pairs of traits exhibit a likely causal relationship.
Authors performed a scan for genetic variants associated with multiple phenotypes by comparing large GWA studies of 42 traits or diseases. They identified 341 loci (FDR, false discovery rate = 10%) associated with multiple traits. Several loci were found to be associated with multiple phenotypes. For example, a nonsynonymous (missense) variant in the zinc/manganese transporter SLC39A8 gene influences seven of the traits––including risk of schizophrenia and Parkinson disease, among others.
Second, authors used these loci to identify traits that have multiple genetic causes in common. For example, variants associated with increased risk of schizophrenia also tended to be associated with increased risk of inflammatory bowel disease (IBS). Finally, authors developed a method to identify pairs of traits that show evidence of a causal
relationship. For example, they show evidence that increased body mass index (BMI) causally increases triglyceride levels.
Nature Genet July 2o16; 48: 709–717 [main article] and 707–708 [News’n’Views]