relatively rare phenotypes such as AN. Statistical power was particularly weakened as case numbers dropped with the increasingly restrictive definitions of AN. Our approach to case definition was based on previous findings (i.e., stronger linkage signals with more restrictive case definitions). However, there are two concerns with narrowing the case definition: (1) statistical power is reduced, and (2) other case definition restrictions may lead to different results. In addition, although our strategy of selecting high-probability candidate genes was scientifically defensible, it is noteworthy that many genetic variants identified by genomewide association studies have not emerged from lists of “usual suspects” and have been genes previously not thought to be involved in the target disease etiology [Psychiatric GWAS Consortium (PGC), 2009].
