Canadian researchers announced yesterday that they have discovered a gene for schizophrenia that is distributed across ethnic lines, making the tangled genetics of the disease much less confusing.

Until the discovery, any gene linked to the disease in one population's DNA had almost no correlation with that of another ethnic group's DNA.

"We can't even replicate stuff found in Finland with stuff found in Iceland," said University of Minnesota researcher Irving Gottesman.

"This has been enormously dispiriting for the research community," added Philip Seeman, a University of Toronto professor of pharmacology and psychiatry and a co-author of the study. Roughly 1 per cent of people worldwide have schizophrenia.

The apparent genetic disconnect led scientists to worry that any gene-based treatment for schizophrenia would have to differ radically from one ethnic group to another.

Prof. Seeman's team reports that 21 per cent of the schizophrenics they studied (17 out of 81 people) carry dual copies of a hyperactive variant of what is called the Nogo gene. By comparison, only two of 61 people in a non-schizophrenic control group had inherited a copy of the gene variant from their mothers as well as their fathers.

There does not appear to be a disease correlation when a person has only one copy of the variant.

Although the researchers examined mainly Caucasians in their study, to be published on Friday in the journal Molecular Brain Research, early results from an expanded version of the study show the same percentages in other ethnic groups, Prof. Seeman said.

In a physiological sense, a connection between the Nogo gene and a predisposition to schizophrenia is not surprising: Nogo produces a protein that inhibits the growth of nerve endings in the brain and elsewhere in the nervous system. It recently has achieved media fame as the "Christopher Reeve gene" because the paralyzed actor's research foundation has supported work aimed at blocking Nogo's action in preventing spinal-cord nerve regeneration.