Humanin (HN) is a multi-functional 24-residue peptide (amino acid sequence: MAPRGFSCLLLLTSEIDLPVKRRA) whose cDNA was isolated from an Alzheimer's disease (AD) patient's occipital lobe of brain, a region that remains generally intact in many AD cases [1] (reviews in [2], [3], [4]). This evidence concerns the gene MT-RNR2 and early-onset autosomal dominant Alzheimer disease.