PROJECT SUMMARY
We propose the Eating Disorders Genetics Initiative 2 (EDGI2), a new collaborative R01 in response to PAR-
23-050 Clinical Studies of Mental Illness. Its single-site predecessors, EDGI1 (R01 MH120170) and ARFID-GEN
(R56 MH129437) have been resoundingly successful. We now unite the four original EDGI1 sites with
exceptionally productive global new sites to advance genomic discovery across all major eating disorders (EDs)
to identify biologically, clinically, culturally, and therapeutically meaningful and actionable insights. Aim 1: EDGI2
extends our core business by increasing sample size, diversity, and ED phenotypes. Using our comprehensive
harmonized online assessment battery, we will phenotype and bio-sample 20,000 new participants with anorexia
nervosa (AN), bulimia nervosa (BN), binge-eating disorder (BED), avoidant/restrictive food intake disorder
(ARFID), and controls. EDGI2 emphasizes co-production—with representatives from minoritized and
marginalized communities, we will ascertain 30% of samples from underrepresented groups. We will also over-
sample individuals with severe and enduring AN (SE-AN), whose DNA may be enriched for causative alleles.
Aim 2: We will apply statistical genetic analyses to explicate heterogeneity and biology of EDs by: conducting
standard GWAS analyses on diagnoses, trans-diagnostic behaviors, and continuous phenotypes including
polygenic risk score (PRS), and rare variant CNV analyses; identifying clinically meaningfully patient subsets;
and intensively evaluating our proposal that AN is a metabo-psychiatric disorders using LDSC, PRSet, pheWAS,
and Mendelian randomization to clarify direction of causation. Aim 3: We will evaluate the relative roles of genetic
and environmental risk and resilience factors to inform risk prediction by phenotypically characterizing cases and
controls with high and low PRS for EDs and then by genotypically characterizing those with severe ED
phenotypes. We will characterize distinct genetic or molecular groupings/patterns across cases and controls and
phenotypically characterize identified molecular subtypes. Aim 4: To determine where in the body EDs “live”, we
will identify brain cell types and anatomical regions implicated by genomic studies of EDs; predict genetically
regulated gene expression (GREx) in brain, gut, adipose, and other ED-relevant tissues; use snRNAseq atlases
to sharpen preliminary GTEx and TWAS analyses to identify brain cell types strongly implicated by the genomics
of each ED; expand to relevant non-brain cell types (e.g., adipose, muscle, liver, salivary); and use dynamic
GREx to model gene expression in ED-relevant contexts (e.g., sex, BMI, stress) enabling precise and
personalized modelling of gene expression. Aim 5: EDGI2 will culminate in a Translational Summit uniting
forward-thinking stakeholders from multiple sectors to develop a translational roadmap for evidence-based ED
prevention and treatment. EDGI2 will yield critical knowledge about genetic and environmental risk for EDs,
reveal mechanisms that potentiate or protect against genetic risk, and transition ED genetics from discovery to
clinical translation.