There is a vast literature on a role for polyanionic compounds, including HS in prion disease pathogenesis, as they colocalise with PrPC on the cell surface and with aggregated PrPSc [29], act as potential co-factors in prion replication, and there is potent inhibitory activity of HS and related compounds on prion propagation [30]. The gene discussed is PRNP; the disease is prion disease.