Recent advances in proteomic, transcriptomic and genomic technologies have revealed much about the ACT protein and gene. In this review, we summarize our current understanding of the structure and potential physiological roles of the ACT protein, catalogue the regulatory elements that have been implicated in expression of the ACT gene, describe its tissue-specific expression and list the single nucleotide polymorphisms (SNPs) within the gene that track ACT variability. The ACT gene has been implicated in a number of complex human disorders and its potential involvement as a risk factor for Alzheimer's disease has been the subject of intensive research. However, due to previous limitations in methodologies and inadequate sample numbers the data has been conflicting with many studies failing to be replicated. In this regard, we highlight some potential approaches, which may prove to be beneficial in future studies.