Caskey's research over a period of more than 50 years has focused on the genetic basis of human diseases and their molecular diagnosis. He discovered the molecular basis of disease "anticipation" as an expansion of short tandem repeat DNA sequences causative of FragileX, Myotonic Dystrophy, Ataxia, and now over 40 additional diseases (Giovanni Herenzini Foundation Prize). One of his more widely used discoveries was that of a simple PCR test for DNA evidence at crime scenes that is now standard practice among police services in the western world. (Courage in DNA Award, DOJ). It was first validated to clarify Gulf War casualties.