SLC30A1 and Alzheimer disease: Two earlier studies have shown that ZnT1 is decreased significantly in the hippocampus of subjects with MCI (a stage from which 30% progress to develop dementia) and pre-clinical AD (PCAD; where subjects have no overt clinical manifestations of AD but pathology is revealed post-mortem) (Lovell et al., 2005), as well as in AD.