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

Background Apolipoprotein E ε4 (APOE ε4) is a risk factor for β-amyloid deposition in Alzheimer's disease dementia. Its influence on β-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 ε4 and PiB status, as well as severity and regional distribution of PiB, was assessed. Results Forty-five subjects had an APOE ε4 allele and 60 subjects were PiB-positive. The odds ratio for a subject with APOE ε4 being PiB-positive compared with a subject without APOE ε4 being PiB-positive was 10.2 (95% confidence interval, 4.4-25.5; P <.0001). The APOE ε4 allele did not influence regional PiB distribution or severity. Conclusion APOE ε4 increases the risk of β-amyloid deposition in PPA and progressive speech apraxia but does not influence regional β-amyloid distribution or severity.