Eating disorder ARFID found to be highly heritable

Researchers at Karolinska Institutet and the University of North Carolina School of Medicine have investigated the importance of genetic factors for developing ARFID, a serious eating disorder that leads to malnutrition and nutritional deficiencies. The disease is characterised by the avoidance of certain types of food due to a sensory discomfort because of the characteristics or appearance of food, the fear of choking, a food poisoning phobia or lack of appetite, and is estimated to affect 1–5% of the population.

A cohort of almost 17,000 pairs of twins in Sweden born between 1992 and 2010 participated in the study; a total of 682 children with ARFID between the ages of six and 12 years could be identified. The researchers used the twin method to determine the influence of genes and the environment on the onset of the disease. The results were published in JAMA Psychiatry.

“We know that identical twins share all genes and that fraternal twins share about half of the genes that make people different,” said lead author Dr Lisa Dinkler, a postdoctoral researcher at Karolinska Institutet. “When we then see that a certain character trait is more common in monozygotic twin pairs than in dizygotic twin pairs, it is an indication that there is a genetic influence. We can then estimate the degree to which a character trait is influenced by the genes.”

The researchers discovered that the genetic component for developing ARFID was 79%, meaning that 79% of the risk of developing ARFID can be explained by genetic factors. This suggests the disease is highly heritable, Dinkler said, noting, “The genetic component is higher than that of other eating disorders and on par with that of neuropsychiatric disorders such as autism and ADHD.”

The next step in Dinkler’s research is to study the extent to which ARFID is associated with other psychiatric diagnoses, such as anxiety and depression, neurodevelopmental disorders and gastrointestinal problems. “We will use twin studies to test the extent to which ARFID shares underlying genetic and environmental factors with these conditions,” she said.

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