A new study suggests that family genes can be used to predict eating disorders such as bulimia and anorexia nervosa.

Scientists from the University of Iowa and University of Texas Southwestern Medical Center found two mutations of genes that may be linked to increased risk of developing eating disorders by analyzing the genes of two families with severe cases.

The researchers studied two groups. One is a group of 20 people from three generations of one family – 10 members were diagnosed with eating disorders. The other is composed of 8 members in which six has eating disorders.

The gene in the first group was an estrogen-related receptor alpha (ESRRA), a transcription factor that turns on the expression of other genes. The gene mutation linked with eating disorders lessens ESSRA activity.

However, the gene in the second group is a histone deacetylase 4 (HDAC4), which contradicts with ESRRA. The mutation observed was uncommon because it increases the gene’s activity.

Another important discovery is that the two affected proteins interact with each other – HDAC4 binds to ASRRA and restrains it. The study also showed that the two genes interact in the same signaling brain pathway and the two mutations have the same biological effect.

Michael Lutter, UI assistant professor of psychiatry and senior author of the study, told Iowa City Patch, "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.”

"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 added.

The researchers examined the genes of the two families with severe eating disorders to pinpoint the very rare variants which increase the chances of having eating disorders by 100 percent.

The study therefore concluded that mutations that lessen the activity of a transcription factor, increases the possibility of eating disorders.

The study was was published in the Journal of Clinical Investigation.