Longitudinal effects of sex on pathology accumulation, neurodegeneration and cognitive decline in Presenilin‐1 E280A mutation carriers: preliminary findings from the Colombia‐Boston (COLBOS) biomarker study

Abstract

AbstractBackgroundPrevious work showed that females at risk for autosomal dominant Alzheimer’s disease (AD) due to a single mutation (E280A) in the Presenilin‐1 gene (PSEN1) may have greater cognitive resilience to AD‐pathology and neurodegeneration than males. However, more research is needed to clarify the effect of sex on AD risk and progression. We investigated the effects of sex on rates of amyloid and tau accumulation, neurodegeneration, and memory decline in PSEN1 mutation carriers with and without cognitive impairment, who are genetically determined to develop early‐onset dementia.MethodA total of 66 cognitively unimpaired mutation carriers (mean age of 34.41 +/‐ 4.86 years; 38 females), and 23 cognitively impaired mutation carriers (mean age of 44.91 +/‐ 2.83 years; 17 females) from the Colombia‐Boston Biomarker (COLBOS) study completed baseline cognitive assessments. A subset of 52 participants also completed florbetapir‐ and flortaucipir‐PET, and structural MRI. Cognitive and neuroimaging follow‐up visits were completed at 2‐ (n = 29) and 4‐year (n = 13) intervals. We used linear mixed‐effects models, with random intercepts, to predict rate of change in MMSE scores, CERAD word list delayed recall, cortical amyloid burden, tau in the entorhinal, inferior temporal, and precuneus cortices, and hippocampal volume by sex, controlling for education.ResultOver time, carriers exhibited greater cortical amyloid burden (p<.001), inferior temporal tau (p = .019), precuneus tau (p = .003), lower hippocampal volume (p = .005), and showed a trend towards lower MMSE scores (p = .059) and word list delayed recall (p<.080); entorhinal tau did not significantly increase (p = .137). Female carriers showed a steeper decline in word list delayed recall than male carriers (p = .021). There were no sex differences in the rate of accumulation of mean cortical amyloid or regional tau, hippocampal atrophy, or change in MMSE scores (all ps>.05).ConclusionPreliminary findings of this ongoing study suggest that despite similar rates of pathology accumulation or atrophy between female and male PSEN1 E280A carriers, female mutation carriers may have faster memory decline. Future analyses with additional participants and follow‐up intervals are needed to characterize sex differences in ADAD risk and resilience, as well as inform development of treatments and interventions.