Human synapses between brain neurons, with C4 proteins marked in green.
Researchers examined the ways in which genes can increase a person’s risk of developing schizophrenia. They examined a gene in our immune system called complement component 4, referred to as C4, whose structure varies considerably between individuals. It was found that certain people with specific forms of the C4 gene stand a higher chance of developing schizophrenia.
That risk is tied to a natural process called synaptic pruning, in which the maturing brain discards weak or redundant connections between neurons. And individuals whose C4 genes increase that pruning effect appear to have a greater chance of developing schizophrenia.