WEDNESDAY, Oct. 26, 2011 (HealthDay News) -- The genes suspected of causing autism, schizophrenia and other mental illnesses are activated in the developing brain before birth, according to a major genetic analysis.
The study by researchers at Yale University also spotted hundreds of genetic differences between males and females still in the womb.
"We knew many of the genes involved in the development of the brain, but now we know where and when they are functioning in the human brain," said study senior author Nenad Sestan, an associate professor of neurobiology and researcher for Yale's Kavli Institute for Neuroscience, in a university news release. "The complexity of the system shows why the human brain may be so susceptible to psychiatric disorders."
In conducting the study, researchers examined more than 1,300 tissue samples taken from 57 people at different stages of brain development, ranging from 40 days after conception to 82 years. They tracked thousands of human genes to determine which are involved in development, where they are located and when they are "expressed," or activated.
The study, published in the Oct. 27 issue of the journal Nature, revealed a significant amount of the human brain is shaped before birth. For instance, the researchers found proof that genes linked to autism and schizophrenia are activated while in the womb.
"We found a distinct pattern of gene expression and variations prenatally in areas of the brain involving higher cognitive function," said Sestan in the news release. "It is clear that these disease-associated genes are developmentally regulated."
The study also found distinct differences before birth in many genes shared by both sexes.
The U.S. National Institute of Mental Health provides more information on the link between genetics and mental illness.