Where are the genes? The implications of a network perspective on gene hunting in psychopathology. [A commentary on Johnson et al.].

The missing heritability problem is pervasive and Johnson, Penke and Spinath (2011) present a number of compelling reasons for its existence. In this comment, we present another reason for the apparent discrepancy between heritability estimates and gene‐hunting results in psychopathological research: if syndromes are networks of causally related symptoms in which both symptoms and relations between them are driven by different sets of genetic polymorphisms, then gene hunting based on a phenotypic sumscore might be ill‐advised because it will only capture genetic variance shared among those symptoms and their relations.