Fabry nephropathy: a treatable cause of chronic kidney disease

Abstract

Fabry disease is a rare X-linked inborn error of metabolism that has a high prevalence of chronic kidney disease (CKD) and renal failure. It is due to the deficiency of the α-galactosidase A (α-Gal) lysosomal enzyme with subsequent accumulation of globotriaosylceramide (Gb3) in lysosomes. In the kidney, the podocyte is the main target of this disease, although all cell types are involved. The podocyte, being terminally differentiated, does not replicate and thus accumulates Gb3 throughout life. Podocytes are injured by Gb3, leading to their detachment from the glomerular basement membrane and subsequent loss in the urine. Albuminuria starts in childhood and progresses to overt proteinuria in the teens and 20 s. CKD ensues with adults starting dialysis at an average age of 42 years. Patients have a high prevalence of stroke and cardiomyopathy with hypertrophic change, heart failure, and dysrhythmias. Patient survival is limited in both genders. Diagnosis is based on the demonstration of a low α-Gal activity and a pathogenic GLA mutation. Clinical features are highly variable, which makes recognition of this condition difficult. Treatment with intravenous recombinant human enzyme replacement therapy (ERT) and oral pharmacologic chaperone are available. Control of proteinuria to 0.5 g/day or less is of critical importance to limit progression to end-stage renal disease. Early initiation of treatment gives the best results, but the optimal age to start is uncertain. Fabry nephropathy remains a challenge due to its multisystem nature, difficult diagnosis, and complicated management. It is important as a treatable cause of CKD.