Age and sex are associated with Alzheimer's disease neuropathology in Down syndrome.

INTRODUCTION

This study investigates the association of age and biological sex with Alzheimer's disease (AD) neuropathology in Down syndrome (DS).

METHODS

We examined the frontal/occipital cortex in people with DS (n = 14/13, 1-39 years), DS with AD (DSAD) neuropathology (n = 18/19, 42-61 years), late-onset AD (n = 15/16, 72-96 years), and age-matched controls (n = 50/47)(n = 156). The area occupied by AT8 and 6E10 immunolabeling, representing tangle and plaque loads, respectively, was used for segmented linear regression analyses.

RESULTS

There was elevated neuropathology after age 35 in DSAD, with inflection points at ∼31 years (amyloid-β [Aβ]) and ∼28 (phosphorylated tau [p-tau]) in the frontal cortex and ∼36 years (both Aβ and p-tau) in the occipital cortex. Occipital p-tau was higher in women relative to men with DS. Aβ and p-tau pathology were correlated in women with DS but not in men with DS in the occipital cortex.

DISCUSSION: Women with DS may show a more advanced stage of tau pathology relative to men with DS.

HIGHLIGHTS: Amyloid-β (Aβ) and phosphorylated tau (p-tau) Alzheimer's disease (AD) pathology emerge after 30 years of age in the frontal cortex, followed 7 years later by pathology in the occipital cortex in Down syndrome (DS). Women with DS show a more rapid progression of AD neuropathology seen by trends in higher p-tau relative to men, despite similar levels of Aβ. Women with DS show a stronger association between Aβ and tau in the occipital but not frontal cortex relative to men with DS, independent of age.