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Scientists have long known that eating disorders like anorexia nervosa and bulimia often run in families. While it has been challenging to pinpoint specific genes that heighten a person's risk, a new study has linked two gene mutations to an increased likelihood of developing these complex disorders.

Researchers at the University of Iowa and University of Texas Southwestern Medical Center found that the two genes interact in the same signaling pathway in the brain, and that they produce the same biological effect.

Researchers say that the newly identified pathway might represent a new target for understanding and potentially treating eating disorders.

"If you're considering two randomly discovered genes, the chance that they will interact is small. But, what really sealed the deal for us that the association was real was that the mutations have the same effect," senior study author Michael Lutter, M.D., Ph.D., UI assistant professor of psychiatry said in a news release.

The latest study linked mutations that decrease the activity of a transcription factor -- a protein that turns on the expression of other genes -- called estrogen-related receptor alpha (ESRRA) to an increased risk of eating disorders.

The first gene, called the ESRRA, is a transcription factor that turns on the expression of other genes. However, the mutation associated with eating disorders decreases ESSRA activity.

The second gene, called the histone deacetylase 4 (HDAC4), turns off transcription factors, including ESRRA. While most mutations decrease or destroy a gene's activity, this particular mutation is usual because it increases the gene's activity, according to researchers.

Researchers also found that the two affected proteins interacted with one another as HDAC4 binds to ESRRA and inhibits it.

"The fact that the HDAC4 mutation happens to increase the gene activity and happens to increase its ability to repress the ESSRA protein we found in the other family was just beyond coincidence," Lutter explained.

Previous studies revealed that these two genes are involved in metabolic pathways in muscle and fat tissue, and that they are regulated by exercise.

While HDAC4 is known to regulate genes that form connections between brain cells, researchers said there is almost nothing known about ESRRA in the brain besides that fact that it is expressed in many brain regions that are disrupted in anorexia.

Researchers said the next step is to study the role of these genes in mice and cultured neurons. They also want to find out if there are ways to modify the genes' activity to see if there is potential to develop therapies for eating disorders.

The findings are published in the Journal of Clinical Investigation.