RNA splicing errors have been estimated to occur in a third of genetic diseases. To understand pathogenesis and identify potential targets of therapeutic intervention in these diseases, explicating the splicing elements involved is essential. Determining the complete set of components involved in splicing presents many challenges due to the abundance of alternative splicing, which occurs in most human genes, and the specificity in which splicing is carried out in vivo.  Splicing is distinctly conducted from cell type to cell type and across different stages of cellular development. Therefore, it is critical that any in vitro or bioinformatic assumptions about splicing regulation are confirmed in vivo.   Minigenes are used to elucidate cis-regulatory elements, trans-regulatory elements and other regulators of pre-mature RNA splicing in vivo. Minigenes have been applied to the study of a diverse array of genetic diseases due to the aforementioned abundance of alternatively spliced genes and the specificity and variation observed in splicing regulation. The following are examples of minigene use in various diseases. While it is not an exhaustive list, it does provide a better understanding of how minigenes are utilized.