APOE and early-onset autosomal dominant Alzheimer disease: No mature NFTs were reported, but this study showed apolipoprotein E (APOE) immunoreactivity, similar to human Alzheimer's disease, suggesting a human-like involvement of the APOE gene in Aβ plaque formation.92 This dolphin showed no signs of cognitive dysfunction but was found with undigested fish in the stomach (usually indicative of sudden death as there is rapid transit of ingesta in cetaceans) and evidence of drowning, which may indicate some form of memory loss.