FRAR course on laboratory approaches to aging. "Orphan" phenotypes in gerontological research

It is argued that, in addition to investigations of life span parameters, a large number of biomedically important phenotypes can be profitably studied from a gerontological perspective. These would include "private" patterns of aging, especially in our own species, which exhibits extraordinary genetic heterogeneity. These, as well as a number of relatively common age-associated phenotypes, have been comparatively neglected by the gerontological community, and therefore warrant the designation as "orphan" phenotypes. From a tabulation of examples from each of the major body systems, five are elaborated upon: "hyperhippocampals," defined as individuals with intrinsically enhanced functional reserve in relevant neural circuitry; patients with a heterogeneous set of pathologies collectively referred to as "normal pressure hydrocephalus"; patients with late life activation of herpes zoster; individuals with unusually early onset of loss of olfactory function; and geriatric subjects with unusual sensitivity to "jet lag."