IRISH RESEARCHERS have played a key role in a new discovery about the genetics of schizophrenia. The finding, that rare structural changes in a person's DNA could increase the risk of developing the condition, was reported by two large research consortiums last week in the prestigious journal, Nature.
Trinity College Dublin (TCD) and the Royal College of Surgeons in Ireland (RCSI) contributed to a study by the International Schizophrenia Consortium that trawled through genetic information from over 3,000 people with schizophrenia, as well as matched controls, explained lead researcher Dr Aiden Corvin, who heads the Psychosis Research Group at TCD.
They found that people with schizophrenia had a slightly increased rate of "copy number variation", where chunks of DNA are missing or replicated. They also identified three specific areas - on chromosomes 1, 15 and 22 - where chunks of DNA were deleted in a small number of patients with schizophrenia. "The deletions are pretty big, some could contain 30 or 40 genes," he told The Irish Times.
Meanwhile, a separate, 18-centre research consortium found similar results for schizophrenia from their trawls of genetic information, and published their findings in the same journal.
Dr Corvin said the two consortiums were in contact, and were pleased with the outcome of the two studies: "We were all delighted, the fact that you are getting some consistency confirms the findings."
He described the breakthrough as "a strong foothold" in understanding the complex genetics of schizophrenia, a condition that around 1 per cent of the Irish population will develop over their lifetime.
However, Dr Corvin noted that the numbers of patients on the study showing these DNA variations were small, and the level of risk was difficult to quantify. "For the vast majority with schizophrenia, these are relatively minor risk factors but there might be a small group of people for whom these will be more important risk factors," he said.
And he expressed concern that people may want to undergo tests for variations in these regions of DNA, warning that it is too early to warrant that approach. "They are not characterised well enough for us to be able to talk about risk," he said.
His group will now zone in on the chunks identified by the study, and they are continuing to look at smaller genetic changes that could contribute to the risk of developing the condition.
