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Study identifies psychiatric, metabolic genetic correlates of anorexia

Results from a genome-wide association study indicated a genome-wide significant locus for anorexia nervosa and identified significant genetic correlations with psychiatric phenotypes and metabolic measures.

“Twin studies consistently support a genetic basis for the observed familial aggregation in anorexia nervosa, with heritability estimates in the range of 48% to 74%. Although initial genome-wide association studies were underpowered, the available evidence strongly suggested that signals for anorexia nervosa would be detected with increased sample size,” Laramie Duncan, PhD, of University of North Carolina School of Medicine, Chapel Hill, and colleagues wrote.

To determine significant locus and metabolic genetic correlations in anorexia nervosa, researchers conducted standard association analysis followed by a meta-analysis of the 1,000 Genomes Project, which included 12 case-control cohorts of 3,495 individuals with anorexia and 10,982 controls. Genome-wide common variant heritability between anorexia nervosa and 159 other phenotypes was calculated using linkage disequilibrium score regression.

Single-nucleotide polymorphism-based heritability of anorexia nervosa was 0.2, indicating a significant portion of twin-based heritability is due to common genetic variation.

Researchers identified one genome-wide significant locus on chromosome 12 (rs4622308) in a region previously implicated as a locus for type 1 diabetes and autoimmune disorder.

There were significant positive genetic correlations between anorexia nervosa and schizophrenia, neuroticism, educational attainment and HDL cholesterol.

There were negative genetic correlations between anorexia nervosa and BMI, insulin, glucose and lipid phenotypes.

“We identified the first robust genome-wide significant locus for anorexia nervosa, which is also a previously reported type 1 diabetes and general autoimmune disorder locus,” the researchers wrote. “Perhaps of greater importance is that we find anorexia nervosa to be a complex heritable phenotype with intriguingly large and significant genetic correlations not only with psychiatric disorders but also with multiple metabolic traits. This encourages a reconceptualization of this frequently lethal disorder as both psychiatric and metabolic.” – by Amanda Oldt

Disclosure: Duncan reports no relevant financial disclosures. Please see the study for a full list of relevant financial disclosures.