Amyloid-beta (1-8, A2V) is a truncated form of amyloid-beta (Abeta) that contains a valine to alanine substitution at position 2 of the Abeta numbering convention (Abeta A2V), which corresponds to position 673 of the amyloid precursor protein (APP) numbering convention (APP A673V). An Abeta (1-40) (Abeta40) A2V peptide increases the production of Abeta and the rate and amount of amyloid fibril formation in vitro, effects that can be reduced by coincubation with wild-type Abeta40. Abeta40 and Abeta42 levels are increased in CHO cells expressing the Abeta A2V mutation and in fibroblasts derived from patients with the Abeta A2V mutation. As a homozygous mutation, Abeta A2V is correlated with Alzheimer's disease with distinctive pathological features, but disease does not develop in patients with a heterozygous Abeta A2V mutation.