It Takes a Genome: How a Clash Between Our Genes and Modern Life Is Making Us Sick

Early Onset FAD

A century after the disease was first described, we now have a good sense of the genetic factors leading to the early onset form that runs strongly in families. Three genes have been implicated: the precursor of Aβ and a pair of scissors that release it. These are thankfully rare forms of AD, but there are now more than 300 families in which three generations of early onset Alzheimer’s sufferers have been found. Most of these cases are attributable to one of more than 150 different mutations in the three genes. Some cases also clearly run in families but cannot be ascribed to these genes. For the most part, though, if there is a cluster of relatives all of whom show signs of dementia in their mid- to late forties, geneticists ...