The PGC MDD group recently completed a manuscript that identified 44 genetic loci for MDD (41). This work is notable due to the compressed timescale (two months from final results to submission) as well as demonstrating what the findings can tell us. The individual loci yielded multiple strong candidate genes (e.g., NEGR1, RBFOX1, and SOX5). The findings were associated with clinical features of MDD (e.g., earlier age of onset and recurrent and more severe forms of MDD). Gene expression patterns in prefrontal and anterior cingulate cortex most closely matched the genetic findings (these brain regions also show MRI differences between MDD cases and controls). Genes that are targets of antidepressant medications were strongly enriched for MDD association signals (P=8.5×10−10), suggesting pharmacotherapeutic relevance. The genetic basis of lower educational attainment and higher body mass were putatively causal for MDD whereas MDD and schizophrenia reflected a partly shared biological etiology.
