Many scientists have drawn another blank in their search for a universally applicable genetic explanation for schizophrenia, binding the case for new approaches to researching the illness. A paper by Douglas F. Levison and colleagues report that despite earlier findings to the contrary, there is no close link between schizophrenia and genes on the long arm of chromosome 1.//
The researchers scoured the chromosome in more than 1,900 patients before reaching this conclusion."Schizophrenia is a complex psychiatric disorder," said co-author Dr Ann Pulver of Hopkins University. "It can't be explained by either a single altered gene or a single environmental cause. There are clearly genetic components, but they are likely to be varied and to interact in many ways with non-genetic factors."
She added that it was still possible that genes on chromosome 1 may contribute to schizophrenia, but they would influence only a small proportion of patients. Dr Philip Ward of the US National Institute of Schizophrenia and Allied Disorders said the findings underscored the need for a new method to "get a handle" on the condition.
"A previous study in Science showed that there was a highly significant link to this gene," he said. "However this multicentre study shows that this does not hold across a range of populations." Dr Ward said that since the discovery of the first genetic linkage with schizophrenia, which made the cover of Nature in 1995, genes on chromosomes 6, 8, 13, 22 had been linked to schizophrenia.
"The trouble has been to get the link to replicate across different populations," he said. According to Dr Ward, such findings raise questions about the approach that needs to be taken in research. Schizophrenia is known to involve genetic factors, since people who have relatives with the condition are more likely to have it, with 40 to 60 per cent concordance between identical twins.
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