Schizophrenia Genetic Markers Identified, but Environmental Factors are Relevant too

by Gopalan on Aug 12 2008 12:07 PM

International researchers have identified the genetic markers of schizophrenia, but they say environmental factors too remain relevant.

Single nucleotide (SNP) within ZNF804A gene on chromosome 2 could be associated with increased risk of schizophrenia, researchers say.

Prestigious scientific journals Nature and Nature Genetics recently published the results of three international schizophrenia research teams, all of which identified genetic variations associated with the disease.

Two of the studies identified the same affected regions of the genome while all three provided convincing statistical evidence of particular genetic factors increasing the risk of the disease.

“Together, these three papers represent a landmark week in schizophrenia genetics,” notes Bryan Mowry, University of Queensland Professor of Psychiatry and Executive Director of the Queensland Centre for Mental Health Research (QCMHR). He contributed to a UK-based study and is a co-author of the Nature Genetics paper.

“This is an important step in helping to unravel the challenging biology of schizophrenia.”

Schizophrenia affects approximately one per cent of the world's population and is characterised by disruptions in language, thought, perception, social activity, and volition.

“The human DNA blueprint consists of three billion letters of code, most of which are the same between individuals, but about 10 million of which can take at least two forms,” he said.

“These single nucleotide (SNP) variations are scattered throughout the entire code and particular forms of the letters may either increase risk for a particular disease, or be used as a signpost for nearby variations which cause disease.

“We were able to show, in a very large sample, that a SNP within the ZNF804A gene on chromosome 2 was associated with an increased risk for schizophrenia.”

The investigation drew upon the expertise of more than 50 researchers from 30 international institutions and involved over 7000 schizophrenia sufferers worldwide, including over 400 Australian patients, recruited primarily through QCMHR.

Professor Mowry said that while the results were encouraging, further research was required.

“This finding strongly supports a role for the ZNF804A gene in schizophrenia; however, the associated SNP within this gene is probably just a signpost for one or more disease-causing mutations located nearby,” he said.

“It is crucial that we identify these mutations and work out how they contribute to the symptoms of schizophrenia.

“What we have is a clue to help unravel the genetic basis of this disease, while not forgetting that environmental factors are also involved.”