Explaining missing heritability, however intellectually satisfying, will probably have fewer practical applications as an end in itself than as a means to an end. The ultimate goal of this line of research, as with nearly all research in the genetics of complex disease, is to improve understanding of human physiology and disease aetiology so that more effective means of diagnosis, treatment and prevention can be developed. If a genetic variant(s) was found that opened the door to effective new treatments at low cost and with minimal side effects (LDL-receptor mutations and the statin class of drugs comes to mind), one would probably be content to leave some heritability unexplained. It is the expectation that associations identified by GWAS or other genomic methods will eventually enable effective disease prevention or treatment, either through delineation of the functional properties of variants recognized at present, or identification of new variants in which true functionality lies, that primarily motivates the hunt for missing heritability.
