Although the underlying biology of AN remains incompletely understood, the relative homogeneity of the phenotype, replicated heritability estimates, and encouraging results of the sign tests presented herein strongly encourage continuing this path of discovery. Phenotypic refinement and the identification of biomarkers of illness (independent of biomarkers of starvation) could assist with identification of risk loci. We believe that the surest and fastest path to fundamental etiological knowledge about the biological basis of AN is via GWAS in larger samples.74 This path is notably safe given that it relies on off-the-shelf technology whose utility has been proven in empirical results for multiple biomedical and psychiatric disorders. This approach is cost-effective due to recent sharp decreases in genotyping pricing. Therefore, we believe that accrual of large genotyped AN case-control samples should be an immediate priority for the field.
