by Grant Goad
Researchers at Harvard Medical School, the Broad Institute, and Boston Children’s Hospital have linked a biological process in the brain to an increased risk of schizophrenia in young people.
Synaptic pruning, in which unneeded connections between neurons are eliminated, is a healthy part of adolescent development. When this molecular process takes place in excess, however, the result can be a reduction in grey matter, a condition that’s closely linked to schizophrenia.
C4, a gene that identifies synapses for pruning, generates the protein C4A—when C4 is over expressed, researchers found, the resulting higher level of C4A is a likely cause of excessive pruning in teenagers and young adults, the age when schizophrenia symptoms typically begin to show.
According to a Broad Institute press release, this is the first time that a biological process and a specific gene variant have been causally linked to this devastating disease, a major breakthrough.
The researchers conducted their study with genetic data from 29,000 schizophrenia sufferers, 36,000 controls, and 700 postmortem brains. They also employed mouse models.
About the study results, Bruce Cuthbert, acting director of the National Institute of Mental Health, said, “Because the molecular origins of psychiatric diseases are little-understood, efforts by pharmaceutical companies to pursue new therapeutics are few and far between. This study changes the game. Thanks to this genetic breakthrough we can finally see the potential for clinical tests, early detection, new treatments, and even prevention.”
While it’s possible that drugs will be developed to target and limit excessive synaptic pruning, any advances will probably happen years in the future.
It’s also interesting to note that for many years, researchers have suspected that abnormal synaptic pruning might be implicated in schizophrenia. This study supports some of these early speculations.