Big picture on Alzheimer's is missing some pieces

Subtle changes that contribute to cognitive decline could be flying under the radar.

- Anjana Ahuja

For any crime, there is always an early suspect. For Alois Alzheimer, a Bavarian pathologist who sought to understand the human brain, one paranoid patient's early memory loss was plainly caused by the peculiar protein clumps found in her brain after death.

Alzheimer first revealed evidence of this in 1906. Ever since, scientists have focused heavily on the abnormal build-ups of two particular proteins—amyloid-beta, which forms sticky plaques around brain cells, and tau, which forms tangles within some brain cells—as the cause of Alzheimer's disease.

The disease accounts for most cases of dementia, an umbrella term for diseases that diminish memory, thinking and everyday functioning.

ONE MORE PIECE OF A GIANT PUZZLE A study published in July in Science Advances now adds to the idea that there may be more proteins implicated in cognitive decline than first thought.

By comparing healthy and cognitively impaired rats, researchers at Johns Hopkins University have identified more than 200 proteins that, when misfolded in the brain, seemed to be linked to declining cognition.

Though it is a study on rats rather than humans, the preliminary findings are worth noting for two reasons: First, identifying more rogue proteins could help to pinpoint new drug targets; and second, it suggests that the most obvious answers are not necessarily the whole story.