CAMK4 and early-onset autosomal dominant Alzheimer disease: Interestingly, as in APP23 mice (model of Alzheimer’s disease), we can observe learning and memory deficits in NCKX2 (K+-dependent Na+/Ca2+ exchanger) heterozygous mice, as well as attenuated hippocampal LTP with reduced CaMKII and CaMKIV activity [233].