Anorexia nervosa has a genetic basis

There are currently around 7,500 adolescents in Austria suffering from anorexia nervosa. Girls make up around 95% of those suffering from this serious and protracted disease, which leads to serious health problems due to excessive weight loss. The disease is currently curable in 80% of cases but is still associated with an annual mortality rate of 0.5%. At the present time, the Department of Child and Adolescent Psychiatry at MedUni Vienna is treating around 70 seriously ill adolescents, both as in-patients and out-patients.

Although we already knew from genetic tests on monozygotic twins that genes are approximately 60% responsible for the development of anorexia nervosa, we did not know with any certainty which gene loci were involved. A study initiated by the US University of North Carolina has now been conducted worldwide, involving 220 researchers in international medical centres analysing the genetic material of 3,500 anorexics. It was found that, compared with the control group of 11,000 people, anorexics had a significant locus on chromosome 12 that contributes towards an elevated risk of developing anorexia nervosa.

The researchers also explored whether there was any correlation with other disorders. This revealed that the significant locus lies on chromosome 12, in a region associated with Type I diabetes and autoimmune disorders, as well as insulin metabolism. Moreover, genetic correlations were found between anorexia nervosa, neuroticism and schizophrenia, supporting the idea that anorexia is a psychiatric illness.

Child and adolescent psychiatrist Karwautz regards the findings of this study as significant proof that, in addition to the psychosocial component, biological factors also play an extremely important role in the onset of anorexia nervosa. This has huge implications in terms of improving treatment. Says Karwautz: "Such studies form a basis for providing patients and their relatives with a logical and realistic explanation for this persistent disorder, which is the third commonest disorder in this adolescent age group. Prevention programmes will also benefit from these new findings."