I recommend the Primary Papers
Told you so (see reference).
I missed from the discussion a mention of the stochastic nature of gene expression, and specifically of the age at onset, as an explanation of the incomplete "penetrance" of mutations with a late expression. Penetrance is a dirty word that explains nothing, as many carriers die from other causes before expression of the mutation.
Bruni AC, Montesi MP, Salmon D, Gei G, Perre J, el Hachimi KH, Foncin JF. Alzheimer's disease: a model from the quantitative study of a large kindred. J Geriatr Psychiatry Neurol. 1992 Jul-Sep;5(3):126-31. Abstract
View all comments by Jean-François Foncin