Important New Molecule in the Biology of Dementia

Two molecules — β-amyloid and tau — are important in the biology of Alzheimer disease (AD). Yet, high concentrations of them, alone or together, don't appear to be sufficient to cause the disease.

A team from Harvard evaluated the molecules produced in the brains of older people with preserved cognitive function or with dementia and identified a candidate molecule called REST, which is important in embryonic brain development. REST production is silenced after embryonic development is completed but is turned back on in aging brains. The team discovered that production continues in healthy older people with preserved cognition — but switches off in people with mild cognitive impairment, AD, or one of several other dementing diseases. REST def…