Update: Exploring Genetic Causes Determining Body Weight

Genetic markers continue to point the way to underlying causes of AN, BN, and BED.  By analyzing the genomes of more than 20,000 people in the UK, Dr. Christopher Hübel of Geneva University and his colleagues found similarities between the genetic bases of AN, BN, and BED and those of other psychiatric disorders (Int J Eat Dis. 2021.doi:10.1002/eat.23481). The initial data were gathered from the UK Biobank and the Avon Longitudinal Study of Parents and Children (Eur J Endocrinol. 2004. 151:141). According to Dr. Nadia Micali, one of the co-authors, “The goal of the study was to better understand similarities and differences among all EDs in the role of genes governing body weight.”

The researchers analyzed more than 250 polygenic scores for each person (polygenic scores are used to estimate a person’s risk for a particular disease based on their genetic profiles). The authors calculated polygenic scores for psychiatric disorders such as schizophrenia and obsessive-compulsive disorder and metabolic and physical traits, such as insulin sensitivity, obesity, and high BMI. The higher the score, the greater the genetic risk. The team then examined the associations between the polygenic scores.

The data for those with BN and BED appeared similar and thus were grouped together in this study. Findings showed that while there were strong genetic similarities between AN and binge-type eating disorders, there were also notable differences.  For example, individuals with binge-type eating disorders had higher polygenic scores than did controls for other psychiatric disorders, including depression, schizophrenia, and attention deficit hyperactivity disorder (ADHD), and higher polygenic scores for higher BMIs,  compared to those with AN. As the authors pointed out, a genetic predisposition to a heavier body weight versus a lower body weight may be a determining factor that propels individuals with similar psychiatric genetic risk to develop a particular ED. For example, metabolic and physical components can direct an individual toward developing AN, BN, or BED. The study results also supported a genetic relationship between BED and attention deficit  hyperactivity disorder, or ADHD, which might be linked to greater impulsivity, a trait shared by individuals with AN, BN, and BED.

The authors’ hope is that better understanding of the genetic basis of EDs may follow, and indeed this work seems a further step in that direction.  The authors summarize this as, “Our findings replicate some of the known comorbidities of eating disorders on a genomic level…”

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