A rare gene mutation that increases the risk of developing schizophrenia or bipolar disorder more than tenfold has been identified by medical scientists at Trinity College Dublin.
The researchers said Irish people are “more closely related” than other populations, allowing them to pick up on the mutation in Irish descendants of the person from Northern Europe they believe brought the mutation here in the first place.
Aiden Corvin, professor in psychiatry at the School of Medicine at Trinity and head of the Psychosis Research Group, said the Irish population may be advantageous for this type of gene discovery programme.
“Because of the population history of Ireland, we as a people are more closely related than in more diverse populations, so we were able to pick up on this mutation in the Irish descendants of this person,” said Prof Corvin. “We believe more is to be found in the Irish population and this will help us to reach a more general understanding about the nature of these disorders.”
Scientists examined blood samples from more than 1,564 Irish people with schizophrenia and 1,748 people without to look for small structural variations where genetic material is duplicated or deleted in the genome. They identified five patients where part of a gene called protein-activated kinase 7 was duplicated. Such duplications were not found in the control group.
Once the mutation was identified, researchers were able to check for it in schizophrenia and bipolar disorder samples from a European sample of more than 25,000 people. This confirmed that the duplication, although rare, increased risk of developing schizophrenia or bipolar disorder more than tenfold.
The duplications appeared similar in all cases and the authors found the duplication carriers are all likely to share a single mutation inherited from a distant, common European ancestor.
Prof Corvin said the finding “demonstrates the power of gene discovery to provide new insights into poorly understood but potentially devastating disorders”.
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