For years, epigenetic mechanisms have been considered a possible key factor in the development and maintenance of the eating disorder anorexia nervosa. A current study by the Institute for Gender-Sensitive Medicine at the University of Duisburg-Essen now contradicts the widespread assumption that weight gain during inpatient treatment causes immediate epigenetic changes. The study, published in Scientific Reports, found no consistent changes in DNA methylation patterns among the patients studied.
The analysis included 189 affected individuals and 67 healthy control subjects. Even in three patients who were examined at both the beginning and the end of their inpatient stay, the epigenetic profiles remained stable despite significant weight gain. The NR1H3 gene, which had yielded conflicting findings in previous studies, was of particular focus. Neither increased nor reduced methylation rates could be confirmed in the current, larger cohort. Instead, there was a large inter-individual variation without a uniform pattern.
Epigenetics refers to modifications that influence gene activity without altering the DNA sequence itself. A central mechanism is DNA methylation. This process is considered an interface between environmental factors and biological function, which is why it is also attributed relevance in the regulation of body weight. However, the Essen study suggests that short-term weight gain hardly triggers direct methylation effects.
The researchers point out that epigenetic changes could either be more subtle than could be detected with the chosen methodology, or they may only occur over the longer course of the illness. Furthermore, DNA methylation varies depending on the tissue type, so different results might be visible in other cell types.
Anorexia nervosa is a serious mental illness characterized by severely reduced body weight and restrictive eating behavior. While genetic influencing factors have now been extensively studied, the contribution of epigenetic processes remains open. The data now presented make an important contribution to differentiation, while at the same time clarifying the limitations of current epigenetic explanatory models.
