The finding that blood cells from FD individuals express membrane-bound CD77 (Gb3bonded to the membrane) at fourfold higher levels than healthy controls14 together with the finding that HK2 cells(overexpressing CD77 by silencing the a-GAL gene) decrease CD77 expression afterthree days of treatment with ERT14 haveencouraged studies to investigate the variations in CD77 levels throughout ERT in FDpatients. This evidence concerns the gene GAL and Fabry disease.