ALDH2 and early-onset autosomal dominant Alzheimer disease: ALDH2 is also reported to be neuroprotective against various neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease [7,32,33,34], possibly by removing highly reactive and cytotoxic lipid aldehydes such as 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), and ACR.