Understanding the determinants of exceptional longevity.
Centenarians represent an extreme of life expectancy. They achieve their exceptional longevity in part by lacking genetic variations linked to premature death. Pedigree studies have shown a substantial familial component in the ability to survive to extreme old age, and a recent study demonstrated a locus on chromosome 4 linked to exceptional longevity, indicating the likely existence of at least one longevity-enabling gene in humans. The children of centenarians have markedly reduced relative risks for age-related diseases, particularly heart disease, hypertension, and diabetes, and are a promising model for genetic and phenotypic studies of 1) aging slowly relative to the general population and 2) the delay of and perhaps escape from important age-related diseases. These studies and those of other mammals and lower organisms show great promise for the delineation of important environmental and genetic determinants of aging well.