(HealthDay News) — Cognitively normal (NL) individuals who have two parents with late-onset Alzheimer’s disease (LOAD) have biomarker abnormalities on imaging decades before symptoms appear, according to a study published online February 12 in Neurology.

Lisa Mosconi, PhD, from the New York University School of Medicine in New York City, and colleagues conducted magnetic resonance imaging (MRI), 11C-Pittsburgh compound B (PiB)-positron emission tomography (PET), and 18F-fluoro-2-deoxyglucose-PET in 52 NL individuals (aged 32–72 years; 30% APOE ε4 carriers). The participants were categorized into four demographically balanced groups: maternal (FHm), paternal (FHp), and maternal and paternal (FHmp) family history of LOAD, and negative family history (FH−).

The researchers found that, compared with other groups, NL FHmp exhibited more severe abnormalities in all three biomarkers regarding the number of regions affected and magnitude of impairment. In the FHmp group, PiB retention and hypometabolism were most pronounced, and these were intermediate in FHm and lowest in FHp and FH−. The highest reductions in MRI gray matter volume (GMV) were seen in FHmp, with intermediate reductions in FHm and FHp, compared with FH−. Amyloid-β deposition exceeded GMV loss and hypometabolism exceeded GMV loss (P<0.001) in all FH+ groups, while in FHmp and FHp, but not FHm, amyloid-β deposition exceeded hypometabolism.

“These biomarker findings show a ‘LOAD parent-dose effect’ in NL individuals several years, if not decades, before possible clinical symptoms,” the authors write.

Several authors disclosed financial ties to the pharmaceutical and medical device industries.

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