Scientists have discovered the first genetic variant for anorexia nervosa.
Genetic variation describes the variation in the DNA sequence in each of our genomes. It is what makes us all unique.
A landmark study by researchers from King’s College London, University of North Carolina and Stanford University identified that people with anorexia had a genetic variant on chromosome 12, whereas those without the illness did not.
This chromosome has previously been associated with Type 1 diabetes and autoimmune disorders.
Researchers said the findings could ignite interest in developing or repurposing medications for treatment, ‘where currently none exist’.
It’s estimated that more than 725,000 people in the UK have an eating disorder.
Currently, people with anorexia rely on psychological treatments such as cognitive analytic therapy (CAT), cognitive behaviour therapy (CBT), interpersonal therapy (IPT), focal psychodynamic therapy and family therapy.
They may also be prescribed medication as part of a treatment plan, according to eating disorders charity Beat.
The new study analysed over 10 million genetic variations in more than 3,400 people with anorexia nervosa and over 10,000 people without an eating disorder.
Scientists discovered one genetic variant associated with anorexia nervosa on chromosome 12. This region has been previously associated with Type 1 diabetes and autoimmune disorders.
Lead investigator, Cynthia Bulik, founding director of the UNC Center of Excellence for Eating Disorders and a professor at Karolinska Institutet in Stockholm, Sweden, said: “We also calculated genetic correlations – the extent to which various traits and disorders are caused by the same genes.
“Anorexia nervosa was significantly genetically correlated with neuroticism and schizophrenia, supporting the idea that anorexia is indeed a psychiatric illness.
“But, unexpectedly, we also found strong genetic correlations with various metabolic features including body composition (BMI) and insulin-glucose metabolism. This finding encourages us to look more deeply at how metabolic factors increase the risk for anorexia nervosa.”
Lead geneticist Dr Gerome Breen, of King’s College London’s Institute of Psychiatry, Psychology and Neuroscience, said: “In the era of team science, we brought together over 220 scientists and clinicians to achieve this large sample size. This shows the power of large scale genomics in large samples – without this study we would never have been able to discover that anorexia has both psychiatric and metabolic genetic roots.”
The study was conducted by the Psychiatric Genetics Consortium Eating Disorders Working Group, an international collaboration of researchers at multiple institutions worldwide.
Lead analyst on the project, Laramie Duncan, PhD, of Stanford University, said: “These results highlight the general mechanisms that are important in anorexia nervosa and our consortium will be carrying further, larger studies to characterise the many specific genes and biological pathways that are involved.”
The researchers are continuing to increase sample sizes and see this as the beginning of genomic discovery in anorexia nervosa.