German scientists say they have identified a flawed gene that might be making a form of schizophrenia run in a large family. If they are right, it would be the first mutation known to promote schizophrenia.
But several experts cautioned that the evidence tying the mutation to the disease is weak. An author of the study agreed the finding is only tentative.
"We have no definitive proof," said Dr. Klaus-Peter Lesch, a professor of psychiatry and neurosciences at the University of Wuerzburg in Germany. Unless such a finding is confirmed by further work, it is unclear whether it is real or just a statistical fluke, he said.
Scientists want to identify genes that predispose people to schizophrenia because that could reveal the biology behind the disease, which in turn might lead to better treatments.
In the current issue of the journal Molecular Psychiatry, Lesch and colleagues focus on a family with an inherited vulnerability to "periodic catatonia." People with the disorder may be agitated and be unable to sit still, or not move around at all, or show jerking in their limbs. They also suffer anxiety, confusion and periods of psychosis, a loss of touch with reality that is a hallmark of schizophrenia.
Some other researchers called the disorder uncommon and said the relationship of the disease to ordinary schizophrenia is not clear.
The German scientists found that a mutation in a previously unknown gene, which they named WKL1, showed up in seven family members with the disease, but not in six family members without symptoms.
However, 10 other family members carried the mutation without having the disease. That might mean the mutation does not always make people sick, the researchers said.
But Dr. Ken Kendler, professor of psychiatry and human genetics at Virginia Commonwealth University, said he found the results unconvincing and noted they could simply be due to chance. Dr. Linda Brzustowicz, an associate professor of genetics at Rutgers University, said the results are "only suggestive."
Molecular Psychiatry: www.nature.com/mp
Schizophrenia information: www.nimh.nih.gov/publicat/schizmenu.cfm