CAPN1 and Alzheimer disease: Hence, we examined the status of calpains 1 and 2 in an isoform-specific manner in the synapse during early stage of AD pathogenesis using APPswe/PS1ΔE9 mice, a well characterized mouse model of AD14 and then used post mortem human brain samples to determine if these observations seen in mouse model of AD could be extrapolated to AD as seen in human subjects.