CNV is a type of mutation or change, which implies that large pieces of DNA may exist in several copies have disappeared or have been transposed. In some diseases such changes in the genome may be protective, for example in HIV infection and malaria.
Researchers found changes in the structure of the genes in patients with schizophrenia.
"The results strongly support the notion that schizophrenia may be partly caused by the effects of such structural changes in genes, both across the whole genome and in specific chromosomes," Nature quoted Christina Hultman, associate professor at Karolinska Institutet, as saying.
Up to seven studies relating to a total of 20,000 cases of schizophrenia have been carried out in 2008. Researchers are hoping to take an important step by understanding the biological mechanisms underlying a complex pattern of genes that can be linked to schizophrenia and also what is known as epigenetics, i.e., how genes are switched on and off during the lifespan.
"We anticipate a breakthrough in the near future in research into psychiatric diseases such as schizophrenia, bipolar disease and autism. At the same I wish to stress that in such a complex disease as schizophrenia there is a need for research on both genetic and environmental causes and on treatment and management," said Christina Hultman.
Schizophrenia is a common psychiatric disease, which is believed to be hereditary. There is an increased of schizophrenia among both first-degree relatives (a person's children) and second-degree relatives of people with the disease.
While the search for specific genetic causes in the last ten years has been intensive, but schizophrenia has a complex pattern of heredity, and the results of previous studies have been unclear.
Many research teams have presented several different suggestions for genes that may be involved, including genes that control the development of brain cells.
The results were published today in the scientific journal Nature.