In a study on the SAMP8 mouse model of Alzheimer’s diseases, the expression level of miR-340 was decreased, while BACE1 was increased, indicating the opposite correlation between the levels of miR-340 and BACE1 in the hippocampus of AD mice (Liu et al., 2022). The gene discussed is BACE1; the disease is early-onset autosomal dominant Alzheimer disease.