Measurement of renal function in patients with Fabry disease.

UNLABELLED: Appropriate measurement of the glomerular filtration rate (GFR) is important for the assessment of renal function. This paper reviews the methods used to assess GFR in clinical trials of enzyme replacement therapy (ERT) in patients with Fabry disease, which include inulin clearance, 24-hour creatinine clearance, chromium ethylene diamine tetraacetate (51Cr-EDTA) clearance and cystatin C concentrations. GFR has also been estimated using calculations based on creatinine clearance (the Cockcroft-Gault formula) and the Modification of Diet in Renal Disease (MDRD) equation. Analysis of the results of these studies shows that there are striking discrepancies between estimated and measured GFR. For example, the MDRD equation overestimates GFR in patients with Fabry disease who have normal renal function. In addition, cystatin C has been shown to be of limited use for measuring renal function during ERT, because it is influenced by other factors such as age, gender and weight.

CONCLUSION: The use of exact methods, such as inulin clearance, 124I-iothalamate, 99mTc-DTPA, 51Cr-EDTA and iohexol, appears to be mandatory for a robust evaluation of the effects of ERT on GFR in patients with Fabry disease.