One of the most frightening aspects of caring for a parent with Alzheimer’s is the fear that you too may carry what researchers call the “susceptibility genes” for the disease. It has been recognized for several years that, in many cases, Alzheimer’s disease is hereditary—passed down from generation to generation. For caregivers in these families, the caregiving itself can become a terrifying look into the future.
While there has been disagreement among researchers about the inheritability of all types of Alzheimer’s, the latest research on familial and hereditary causes of the disease will not provide much reassurance for these caregivers. In fact, a recent book entitled Candle and Darkness, by leading Alzheimer’s disease researcher, Dr. Joseph Rogers, asserts that “earlier estimates of the inheritability of Alzheimer’s disease may have been too low.” 1 Until recently, however, researchers had believed that hereditary Alzheimer’s disease was relatively rare, and was considered to strike much earlier, at around age 45. In the past, researchers believed that the average age for nonhereditary Alzheimer’s was about sixty-five to seventy-five.
Today, it is becoming increasingly clear that these previous estimates may have been too low, with respect to both the age of onset for inherited Alzheimer’s disease and also how often inherited Alzheimer’s occurs. Now there is evidence that the frequency of genetically determined Alzheimer’s disease is much greater than previously