Membranous nephropathy without vacuolated podocytes in Fabry disease treated with agalsidase-β and carbamazepine: A case report

RATIONALE: Vacuolated podocytes are the most common form of renal damage in Fabry disease, but other types of renal damage have been reported, such as membranous nephropathy (MN) or IgM nephropathy. Enzyme replacement therapy (ERT) is effective at preventing renal damage, but the nephropathies require appropriate treatment to prevent renal damage. PATIENT CONCERNS: A 22-year-old male with Fabry disease presented with proteinuria during ERT with agalsidase-β and carbamazepine. He had received the treatment for 10 years and maintained normal plasma globotryaosylceramide levels. DIAGNOSIS: Renal biopsy revealed MN without vacuolated podocytes. Immunofluorescent staining of the IgG subclass revealed granular patterns of IgG1, G2, G4, and C3 deposition in the glomerular basement membrane. INTERVENTIONS: The carbamazepine dose was reduced from 600 mg/day to 200 mg/day (serum concentration 10.0-11.0–4.0–5.0 μg/mL). OUTCOMES: After reducing the carbamazepine dose, proteinuria was negative, and the patient has had a normal urinalysis for 17 months. Plasma globotryaosylceramide levels have also remained normal. LESSONS: This report is a reminder of the co-existence of MN without vacuolated podocytes in Fabry disease during ERT with agalsidase-β and carbamazepine. Physicians should be aware of this form of renal damage in Fabry disease, even during treatment.