APOE ε4 influences β-amyloid deposition in primary progressive aphasia and speech apraxia

Background: Apolipoprotein E epsilon 4 (APOE epsilon 4) is a risk factor for beta-amyloid deposition in Alzheimer's disease dementia. Its influence on beta-amyloid deposition in speech and language disorders, including primary progressive aphasia (PPA), is unclear. Methods: One hundred thirty subjects with PPA or progressive speech apraxia underwent APOE genotyping and Pittsburgh compound B (PiB) PET scanning. The relationship between APOE epsilon 4 and PiB status, as well as severity and regional distribution of PiB, was assessed. Results: Forty-five subjects had an APOE epsilon 4 allele and 60 subjects were PiB-positive. The odds ratio for a subject with APOE epsilon 4 being PiB-positive compared with a subject without APOE 64 being PiB-positive was 10.2 (95% confidence interval, 4.4-25.5; P <.0001). The APOE epsilon 4 allele did not influence regional PiB distribution or severity. Conclusion: APOE epsilon 4 increases the risk of beta-amyloid deposition in PPA and progressive speech apraxia but does not influence regional beta-amyloid distribution or severity. (C) 2014 The Alzheimer's Association. All rights reserved.