Childhood phenotypic manifestations of genetic risk for anorexia nervosa in the Norwegian Mother, Father and Child Cohort Study (MoBa)

Anorexia nervosa (AN) polygenic liability has been associated with mental health traits, eating problems, and body mass index (BMI) in adolescence and adulthood, but little is known about its manifestations in early childhood. We explore AN polygenic score (PGS) associations with six childhood domains: BMI, eating problems, neurodevelopment, emotional problems, disruptive/aggressive behaviour, and temperament/personality in 15,205 children from the Norwegian Mother, Father and Child Cohort Study. Results did not support associations between AN PGS and developmental phenotypes in girls. For boys, we observed an association between AN PGS and higher temperamental fussiness at 6 months, (b= 0.036 [95% CI=0.010,0.061]). Our results suggest that genetic risk for AN as indexed by the PGS has few observable manifestations in key neurodevelopmental domains in the first 8 years of life. Future studies with more powerful PGS that track children longer may aid in understanding how and when genetic risk for AN manifest developmentally.