Schizophrenia affects roughly 1 percent of the population, and it’s the disease most mysterious and most frustrating to psychological researchers. It can’t be modeled in animals or cells, making its cause, let alone more effective treatment, close to impossible. But thanks to human genome research, we may have just cracked it.
The study, which looked at the genomes of 65,000 people, found the expression of a gene known as C4. Its protein, C4A, has a number of jobs in the body, including controlling inflammation; lupus patients have a mutated C4 gene. In the brain, though, it serves as a mediator for synaptic growth. Essentially, if your brain is growing too many synaptic pathways, C4A will trim off a few.
People living with schizophrenia, however, have far too much C4A in their brains, according to the study. It appears that over time, the protein begins cutting pathways people need. Those with the disorder have fewer synapses than non-sufferers, so this lines up with previous research.
To be clear, this is a major cause, but it’s unlikely to be the only one. Mental illness is a complex, difficult collection of maladies, and the causes can be as much environmental or psychological as medical. That said, this is a huge puzzle piece in putting together how schizophrenia operates.
This is a far bigger deal than just finding a major cause of schizophrenia, however. The brain is the great final frontier of medical science. We don’t really have a good grasp of how it works, what mechanisms dictate its growth and change, or how proteins that work elsewhere in the body might affect the brain. Uncovering this gene expression is a major breakthrough and will usher in a host of research on mental illness to see how much of it is molecular and how much of it lies elsewhere. Even if we can only remove a piece of the problem, that’s still more progress than we’ve seen in a century.