CHRM1 and Alzheimer disease: The pathogenic role of CHRM1 in AD is supported by the observation that CHRM1 is abundantly expressed in both cerebral cortex and hippocampus in non-demented individuals (Giraldo et al., 1987; Ehlert and Tran, 1990; Levey, 1996) whereas it is severely downregulated in the majority of AD patients (Sabbir et al., 2022).