Five major psychiatric disorders share a common problem in
several faulty genes, according to the biggest study of its kind published on
In the widest trawl yet of genetic mutations linked with
mental disorders, US-led researchers looked through the DNA code of 33 332
people with autism, attention deficit-hyperactivity disorder (ADHD), bipolar
disorder, major depressive disorder or schizophrenia.
How the study was
Their genomes were matched against 27 888
"controls," or people who did not have these illnesses, in a bid to
spot tiny changes in genes.
The five diseases have common risk factors in flaws on
Chromosomes 2 and 10, and in two genes that help regulate the flow of calcium
in brain cells, the investigators found.
One of the genes, called CACNA1C, has previously been
fingered in bipolar disorder and schizophrenia.
The study, published in The
Lancet, says the common genes are part of a much wider picture and do not
by themselves explain the causes of these disorders or why their symptoms vary.
What the results
In addition, the gene samples examined by the Psychiatrics
Genomics Consortium all came people from European ancestry, and the results may
be different for people of different heritage, it said.
But, it added, the findings are a useful step towards better
diagnosis of these illnesses.
Psychiatric disorders are difficult to categorise because
symptoms can be hazy or contradictory, and little is known about their
underlying cause. Environmental factors also play a part.
Previous genome comparisons have found intriguing common
ground in an array of so-called auto-immune disorders, including arthritis,
Crohn's disease and psoriasis.