GWAS explains only a small proportion of the total heritability

By exploiting allied phenotypic data, it is possible to examine the genetic contribution to such aspects of disease biology (including prognosis) by comparing the genetic profiles of patients with contrasting clinical phenotypes—a so-called ‘within-cases’ analysis.

Prognosis in autoimmune and infectious disease: new insights from genetics
Clinical & Translational Immunology (2014) 3, e15
http://www.nature.com/cti/journal/v3/n5/full/cti20148a.html
James C Lee, et al.

Keywords: autoimmunity; FOXO3; genetics; infection; prognosis

despite the apparent success, GWAS results have only explained a relatively small proportion of the total heritability of each disease.[3]
Work is now underway to try to identify the ‘missing heritability’ through a variety of complementary methods, including:

  • whole-genome sequencing (to identify rare variants that may have larger effect sizes) and
  • studies to examine interactions between a given gene and other genes (epistasis) and
  • between genes and the environment.

related:
https://franzcalvo.wordpress.com/2014/06/29/are-vitamins-good-for-you