Progressive renal failure despite long-term biweekly enzyme replacement therapy in a patient with Fabry disease secondary to a new α-galactosidase mutation of Leu311Arg (L311R).

A 37-year-old Japanese man affected by Fabry disease secondary to a novel mutation of Leu311Arg (L311R) in α-galactosidase demonstrated progressive renal failure despite biweekly enzyme replacement therapy (ERT) for approximately 10 years. Kidney biopsy revealed foamy glomerular epithelial cells, compatible with the typical pathologic features of Fabry disease. The patient entered a phase III study of Replagal (agalsidase alfa) in 2001, allowing him to continue ERT with biweekly dosing for almost 10 years. During 2 years of that period, he was continued on Fabrazyme (agalsidase beta) biweekly dosing. His estimated GFR was calculated to decrease by 9.9 mL/min/1.73 m(2) per year. Patients with Fabry disease have been reported to have a mean decrease in GFR of 12.2 ± 8.1 mL/min/1.73 m(2) per year. This result suggests that biweekly ERT is only mildly effective at preventing loss of kidney function.