遺伝子と疾患（表現形）との強い相関と弱い相関が見られるが中程度の相関がみられないという謎(missing)のことらしい。

• missing heritability

それだけ、環境要因が強いということなのだろうか？

The "missing heritability" problem[1][2][3][4][5] can be defined as the fact that individual genes cannot account for much of the heritability of diseases, behaviors, and other phenotypes. This is a problem that has significant implications for medicine, since a person's susceptibility to disease may depend more on "the combined effect of all the genes in the background than on the disease genes in the foreground".Missing heritability problem