Researchers have made progress in understanding how a variant gene linked to schizophrenia may exert its influence in the brain. The findings are tentative but, if confirmed, could yield deep insights into the biological basis of the disease. The gene, called neuregulin-1, was first implicated in schizophrenia in 2002 by DeCode Genetics, a Reykjavik company that looks for the genetic roots of common diseases... But how the variant form of the gene contributed to the disease was far from clear, in part because even the normal gene's function is far from understood. A team led by Amanda J. Law of...