Two families affected by anorexia and bulimia shed light on the genetic contributors to eating disorders.
Eating disorders, which are included in the Diagnostic and Statistical Manual of Mental Disorders-5, as a psychiatric illness, tend to run in families, and affect about 1% to 3% of women. Experts believe that the distorted body image and altered eating habits associated with anorexia and bulimia are governed by more than cultural pressures to maintain a certain body shape. Genetic factors are likely to contribute to disrupted appetite and satiety signals, but teasing out those gene-based culprits has been challenging.
Now a group of researchers from the University of Iowa and the University of Texas Southwestern Medical Center have identified two mutations, one from each of two families severely impacted by eating disorders, that may contribute to a higher risk of the conditions.
The first gene, discovered in the larger family that involved 20 members, half with eating disorders and half without, was ESRRA. When mutated, the gene not longer turns on the activity of other genes, and this suppressed function is linked to a higher risk of eating disorders. The other gene, HDAC4, which emerged from the second family of eight, six of whom experienced eating disorders, also inhibited gene activity, but in its mutated form, increased expression of certain genes, including ESRRA.
“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,” said study author Dr. Michael Lutter, an assistant professor of psychiatry at the University of Iowa in a statement.
The researchers plan to study how these genes work to affect appetite and eating habits in mice in order to determine whether it’s possible to modify their activity and normalize the changes that contribute to anorexia and bulimia.