New research led by University of California, San Diego (UCSD) School of Medicine, finds that rare copy number variants
(CNVs) where sections of DNA are either duplicated or missing, seem to play a key role in the risk for early onset bipolar
disorder, which appears in childhood or early adulthood. The researchers write about their findings in a paper published online
on 22 December in the journal Neuron
CNVs are a particular type of mutation or alteration in the genome where cells end up with an abnormal number of copies of
sections of DNA code: either too few, due to deletion, or too many, due to duplication. CNVs can be inherited, or de
, the latter spontaneously occuring either in the sperm or unfertilized egg, or even in the egg after it has been
Previous studies have already established that rare CNVs contribute to risk for some some neuropsychiatric disorders such as
schizophrenia and autism, but the role they play in bipolar disorder, formerly known as manic depression
, has been less
Nobody knows what causes bipolar disorder, although we know there is a clear genetic contribution, since the disorder runs in
families. But previous studies that have focused primarily on inherited variants have not been very successful at identifying key
In this latest paper, senior investigator Dr Jonathan Sebat, assistant professor of psychiatry and cellular and molecular medicine at
UCSD's Institute of Genomic Medicine, and colleagues, describe how they found de novo
CNVs contribute significant
genetic risk in about 5% of early onset bipolar disorder.
First author Dheeraj Malhotra, an assistant project scientist in Sebat's lab, said in other words, the study shows that "having a de novo
mutation increases the chances of having an earlier onset of disease".
While such a result is not enough to point conclusively to...