Genetics of Anorexia Nervosa

Abstract

Abstract Anorexia nervosa (AN) is a heritable disorder characterised by an extremely low body weight and food restriction that frequently onsets during adolescence. However, AN is observed across the lifespan. A majority of twin studies reveal that genetic factors, on average, account for between 40% and 60% of the liability to AN. Candidate gene studies exploring the molecular genetic basis of AN have primarily focussed on genes in the serotoninergic and dopaminergic pathways. Although no pathway or gene has been unequivocally demonstrated to play a causal role in AN, 5‐HTTLPR , 5HT2A , DRD2 and DRD4 are noteworthy candidates from the serotonin and dopamine systems. Genome‐wide association studies have not yet revealed any genes meeting genome‐wide significance for AN. However, sample sizes have been small and underpowered, underscoring the need for much larger samples. Key Concepts: Anorexia nervosa is, on average, estimated to be 40–60% heritable. Chromosome 1 has received some support for harbouring a region of interest for AN. Candidate gene studies of AN have provided inconclusive results. Genes in the serotonin, dopamine and opioid systems have shown some positive associations with AN. Genome‐wide association studies have not revealed significant findings for AN, although they have been underpowered. The genetic architecture of AN is likely complex, representing a synergistic interaction between many genetic and environmental factors.