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Gene Mutation May Cause Bipolar Disorder

Source: Molecular Psychiatry 
(c) HMG Worldwide 2003' 
Publication: HMG - Health Newswire Professional 
Distributed by Financial Times Information Limited 
Health Newswire Professional -- 06/17/03

ABSTRACT:  OHMG - Health Newswire Professional via NewsEdge Corporation : The team, from the University of California in San Diego (UCSD), say that in up to 10 per cent of bipolar cases, a mutation in the gene G protein receptorkinase 3 (GRK3) causes bipolar disorder. 

The mutation occurs in the promoter area of the gene, which has a regulatory function when it is turned on, say the researchers. 

GRK3 regulates sensitivity to brain neurotransmitters such as dopamine, but a mutation in the gene can cause the individual to become hypersensitive to the drug, leading to the mood swings that characterise the illness, speculate the researchers. 
While previous research had suggested candidate genes or general DNA regions where faulty genes might reside, the study from UCSD is the first to pinpoint a precise gene involved in the disease. 

Dr John Kelsoe, senior author of the study, says the discovery of genetic defects that cause bipolar disorder may lead to the development of new drugs that target specific genes. 

The team of authors, writing in the journal Molecular Psychiatry, spent a year screening DNA samples from more than 400 families with bipolar disorder. 
They discovered that there were six mutations in the promoter region of the GRK3 gene, and that one of these, P-5, occurred three times more frequently in patients with bipolar disorder than in people without the condition. 

Co-author Dr Thomas Barrett explains, P-5 is in the region of GRK3 that controls when the gene turns on and off. A defect in P-5 affects regulation of the gene. It may be turning on inappropriately, or turning off when it shouldn't.