“Persistent Thinness and Anorexia Nervosa Differ on a Genomic Level”, Christopher Hübel, Mohamed Abdulkadir, Moritz Herle, Alish B. Palmos, Ruth Loos, Gerome Breen, Nadia Micali, Cynthia M. Bulik2024 (exercise, genetic correlation, ADHD, anorexia, depression)⁠:

Thinness and anorexia nervosa are both characterised by persistent low weight. Individuals with anorexia nervosa concurrently report distorted perceptions of their body and engage in weight-loss behaviors, whereas individuals with thinness often wish to gain weight. Both conditions are heritable and share genomics with BMI, but are not genetically correlated with each other. Based on their pattern of genetic associations with other traits, we explored differences between thinness and anorexia nervosa on a genomic level.

In Part 1, using publicly available data, we compared genetic correlations of persistent thinness/anorexia nervosa with 11 psychiatric disorders. In Part 2, we identified individuals with adolescent persistent thinness in the Avon Longitudinal Study of Parents and Children (ALSPAC) by latent class growth analysis of measured BMI 10 → 24 years (n = 6594) and evaluated associations with psychiatric and anthropometric polygenic scores.

In Part 1, in contrast to the positive genetic correlations of anorexia nervosa with various psychiatric disorders, persistent thinness showed negative genetic correlations with attention deficit hyperactivity disorder (r_gAN = 0.08 vs. rgPT = −0.30), alcohol dependence (r_gAN = 0.07 vs. rgPT = −0.44), major depressive disorder (r_gAN = 0.27 vs. rgPT = −0.18) and post-traumatic stress disorder (r_gAN = 0.26 vs. rgPT = −0.20).

In Part 2, individuals with adolescent persistent thinness in the ALSPAC had lower borderline personality disorder polygenic scores (OR = 0.77; Q = 0.01).

Overall, results suggest that genetic variants associated with thinness are negatively associated with psychiatric disorders and therefore thinness may be differentiable from anorexia nervosa on a genomic level.