Amyloid-β (1-8, A2V) is a truncated form of amyloid-β (Aβ) that contains a valine to alanine substitution at position 2 of the Aβ numbering convention (Aβ A2V), which corresponds to position 673 of the amyloid precursor protein (APP) numbering convention (APP A673V). An Aβ (1-40) (Aβ40) A2V peptide increases the production of Aβ and the rate and amount of amyloid fibril formation in vitro, effects that can be reduced by coincubation with wild-type Aβ40. Aβ40 and Aβ42 levels are increased in CHO cells expressing the Aβ A2V mutation and in fibroblasts derived from patients with the Aβ A2V mutation. As a homozygous mutation, Aβ A2V is correlated with Alzheimer's disease with distinctive pathological features, but disease does not develop in patients with a heterozygous Aβ A2V mutation.