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Singh, Karanvir

University of British Columbia

Eating disorders (EDs) are severe psychiatric conditions with significant physical and psychosocial impacts. Anorexia nervosa (AN), characterized by severe restriction of energy intake, fear of weight gain, and distorted body image, has one of the highest mortality rates out of all psychiatric conditions. Low body weight is part of the diagnostic criteria for AN, but individuals can experience the psychological symptoms associated with AN regardless of their body weight. Genes account for 48-74% of AN risk, and a recent genome-wide association study (GWAS) found significant genetic overlap between AN and metabolic and anthropometric traits such as body mass index (BMI). In Chapter 1, I use a novel statistical method (“GWAS-by-subtraction”) to further explore the overlap between BMI and AN and identify the genetic architecture of AN that is independent of BMI. I find that BMI explains only a small amount of variance in AN (~10%), and that the genetics of AN are robustly shared with other psychiatric conditions independently from BMI. Despite the strong evidence that genetic factors play a significant role in AN's etiology, the early-life manifestations of genetic risk for AN remain unclear. In Chapter 2, I investigate the association between genetic predisposition to AN, measured by polygenic scores (PGS), and childhood psychopathology and BMI trajectories. I found no robust associations between genetic predisposition to AN and childhood psychopathology, suggesting that genetic risk for AN may not manifest as early as age 5. I found an unexpected association between genetic risk for AN and higher BMI during the first five years of life, which was robust to conditioning on the genetics of BMI. This suggests that children with a high genetic risk for AN might have higher BMI during early childhood compared to their peers. My findings support the conceptualization of AN as a metabopsychiatric condition, with underlying metabolic and psychiatric genetic vulnerabilities that have small effects on childhood physical growth. Replication in a larger cohort before further interpretation is required.

Text

2024-07-29

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88717

Bioinformatics

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/