Fainting: All in the family?

Fainting has a strong genetic predisposition, according to new research published in the August 7, 2012, print issue of Neurology, the medical journal of the American Academy of Neurology. Fainting, also called vasovagal syncope, is a brief loss of consciousness when your body reacts to certain triggers, such as emotional distress or the sight of blood.

"The question of whether fainting is caused by , environmental factors or a mixture of both has been the subject of debate," said study author Samuel F. Berkovic, MD, FRS, with the University of Melbourne in Victoria, Australia, and a member of the American Academy of Neurology.

For the study, 51 sets of twins of the same gender between the ages of nine and 69 were given a telephone questionnaire. At least one of the twins had a history of fainting. Researchers also gathered information about any family history of fainting. Of the 51 sets of twins, 57 percent reported having typical fainting triggers.

The research found that among twins where one fainted, those who were identical (from the same fertilized egg) were nearly twice as likely to both faint compared to fraternal twins (those from two different fertilized eggs). The risk of fainting not related to outside factors (such as dehydration) was also much higher in identical twins compared to fraternal twins. Identical twins were much more likely to both experience fainting associated with typical triggers than fraternal twins. The frequency of fainting in non-twin relatives was low, suggesting that the way fainting is inherited is usually not by a single gene.

"Our results suggest that while fainting appears to have a strong , there may be multiple genes and multiple environmental factors that influence the phenomenon," said Berkovic.

Related Stories

Study shows fainting factor in cardiac arrests

date Feb 09, 2012

A new study by Dr. Andrew Krahn shows that over a quarter of unexplained cardiac arrests occurred after the patient had an event of fainting, known as syncope. According to Dr. Krahn, a Cardiologist at London Health Sciences ...

Recommended for you

Diet rich in methionine may promote memory loss

date 7 hours ago

Memory loss has recently been associated with excessive silencing of genes through a process called methylation. Researchers at the University of Louisville investigated the effects of a diet rich in methionine—an amino ...

Intelligent neuroprostheses mimic natural motor control

date 20 hours ago

Neuroscientists are taking inspiration from natural motor control to design new prosthetic devices that can better replace limb function. In new work, researchers have tested a range of brain-controlled devices ...

Researchers create 'Wikipedia' for neurons

date Mar 30, 2015

The decades worth of data that has been collected about the billions of neurons in the brain is astounding. To help scientists make sense of this "brain big data," researchers at Carnegie Mellon University ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.