Nature, Nurture, and Family Predisposition

Abstract

Both genes and a shared environment can endow members of a family with a predisposition to the same disease. Familial aggregation has been reported for most common diseases (cardiovascular, neoplastic, emotional, and endocrine, among others).^{1 2 3 4} Causal factors that affect a person's susceptibility or resistance to a particular disease can generally be derived either from genes (nature) or from the environment (nurture). Major effects from a single gene (monogenic trait) are observed in such disorders as familial hypercholesterolemia. The blended effects of many genes (polygenic traits) often account for approximately 50 percent or more of the variation in the normal population . . .