Understanding the Genetics of Anorexia
News Jan 26, 2011
The team, composed of Scripps Research Professor Nicholas Schork, a genomics researcher and director of biostatistics and bioinformatics with Scripps Translational Science Institute (a collaboration between Scripps Research, Scripps Health, and other institutions), Dr. Cinnamon Bloss, a clinical psychologist, and Dr. Ashley Van Zeeland, a neuroscientist, believes that a better understanding of the genetic variations associated with eating disorders could lead not only to better treatments, but could also shed light on other disorders such as autism, obesity, and obsessive compulsive disorder.
As with many other diseases, genetic variants may not guarantee that a patient will develop a disease, but might tell doctors who is most susceptible.
Last year, Dr. Bloss and Dr. Schork collaborated with scientists at The Children's Hospital of Philadelphia on the largest genetic study ever on anorexia. The project identified both common and rare genetic variants associated with the disease, but the team says the study was just a first step.
"Now we're kicking it up in gear," Dr. Schork said. "We're working on a study that looks at 150 genes thought to play a role in anorexia and we're spelling out all of the variations in those genes."
The team is not treating all anorexia patients the same, though. By dividing them into sub-groups – for example, separating the patients who restrict their caloric intake from those who binge and purge – the team is able to refine their search and increase the odds that the variants they find will be specific to the disorder.
The study, which will be the first of its kind, has already identified a number of variants never before seen. Now, the scientists are in the second phase, using statistical and physiological analysis to determine whether these variants play a role in anorexia.
One of the most helpful ways of separating the patients may be to look at the genetic differences between people who recover and those who remain chronically ill.
"Anorexia is highly treatment-resistant, nothing really works that well," Dr. Bloss said.
The scientists hope that genetic factors could hold a clue to this. In recent years, research has pointed toward commonalities between people with anorexia and those with autism, including Dr. Van Zeeland's work on social rewards.
"A lot of anorexia treatment is family therapy, but it doesn't work well if you don't understand the social cues," she said. "It doesn't become internalized. Instead of seeing the social world as an exciting place, it becomes anxiety-ridden."
Better understanding of the genetic factors behind anorexia may not only help scientists develop better treatments for the disorder, it may also hold value for other diseases as well. Scientists say that in looking for genetic variants that affect mechanisms related to anorexia – for instance, mechanisms related to feeding – their findings may also apply to overeating. Similarly, in looking at mechanisms related to anxiety, their findings could hold helpful information for obsessive-compulsive disorder.
"Studying anorexia is important in and of itself, but we are of the mind that whatever we find could shed light on other disorders," said Dr. Schork.
The team also believes that time is of the essence. Anorexia has the highest mortality rate of all psychiatric disorders, including schizophrenia and bipolar disorder.
"Once someone is locked into these behaviors – not eating, exercising all the time, cutting off the rest of the world – it's very hard to get them out of that trough," Dr. Schork said. "If you can't help, then people will die."
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