Although it was initially reported that plasma levels of ghrelin were not changed in patients with Alzheimer’s disease [177], Gahete and colleagues later reported that several components of the ghrelin system, including ghrelin, GOAT and GHSR, were reduced in the temporal gyrus in the brain of patients with Alzheimer’s disease [178]. This evidence concerns the gene GHRL and early-onset autosomal dominant Alzheimer disease.