Provided for are three novel isoenzyme variants of the human Hyaluronan Synthase gene, HAS1Va, HAS1Vb, and HAS1Vc. Also provided is a method for assessing disease, or susceptibility to disease, in a patient; in which a cell or sample of a cell population is mixed with at least one compound which specifically binds to HAS1Va, HAS1Vb, HAS1Vc or HAS2 isoenzyme or isoenzyme variant genomic mRNA transcript or products arising therefrom; and methods of treatment.