Scientists have for the first time identified a gene that can cause mental illness on its own.
The idea of a single gene for complex traits — whether height, intelligence, mental health, or sexuality — has largely fallen away. Instead, sequencing has revealed that they are almost always polygenic, with hundreds of genes having subtle effects, rather than the product of a “candidate gene.”
But having a copy of a particular variant of GRIN2A raised schizophrenia risk 87-fold, and other conditions by a smaller degree. It’s a rare win for the older model, though it still only accounts for a tiny fraction of all schizophrenia cases; generally, scientists have found genetics to be far more complex than early, optimistic claims suggested.