deCODE and SGENE Consortium Discover Deletions in the Human Genome Linked to Risk of Schizophrenia
News Aug 04, 2008
In a major paper published in the online edition of the journal Nature, scientists from deCODE genetics and the University of Iceland, along with academic colleagues from the deCODE-led European SGENE consortium, China and the United States, report the discovery of three rare deletions in the human genome that confer risk of schizophrenia.
Such deletions are gaps in the normal sequence of the genome that can arise spontaneously during the recombination or reshuffling of the genome that takes place in the creation of sperm and eggs.
The deletions reported in the study are located on chromosomes 1q21, 15q11 and 15q13, and confer, respectively, 3, 15 and 12 times greater than average risk of schizophrenia. These are the first such deletions to be associated with risk of mental illness using large sample sizes and validated across many populations.
The substantial increase in risk they confer make them a valuable basis upon which to develop molecular diagnostic tests to complement standard clinical diagnosis. The study, ‘Large recurrent microdeletions associated with schizophrenia,’ will appear online at www.nature.com.
“Schizophrenia is a disorder affecting thoughts and emotions. It is therefore a quintessentially human disease, but one that is little understood biologically and which is difficult to diagnose. These findings are important because they shed light on its causes and provide a first component to a molecular test to aid in clinical diagnosis and intervention. These discoveries also demonstrate one way in which we can use SNP-chips to find rarer genetic factors conferring risk of disease,” said Kari Stefansson, CEO of deCODE
“In many disease areas we have had great success of late in identifying what these chips are best suited to find: common variants conferring relatively modest increases in risk. But we know that individuals with certain mental disorders such as schizophrenia tend to have few children, and thus that we may have to identify a larger number of rare but high risk variants to understand the genetic contribution to susceptibility. It is encouraging that our efforts to use SNP chips to detect rarer variations such as spontaneous deletions and duplications is now bearing fruit,” Stefansson continued.
Previous work by the International Multiple Sclerosis Genetics Consortium (IMSGC) has identified 233 genetic risk variants. However, these only account for about 20% of overall disease risk, with the remaining genetic culprits proving elusive. A new study has tracked down four of these hard-to-find genes.READ MORE