Fabry nephropathy and membranous lupus nephritis—an unexplored link

Fabry disease (FD) is an inherited X-linked lysosomal disorder resulting in the deficiency of the enzyme alpha-galactosidase-A. This leads to the accumulation of glycoproteins and glycolipids in various organs. It classically presents in males in the first decade with neuropathic pain, with or without renal involvement. In the kidney, Fabry nephropathy is characterised by the presence of concentric lamellar osmiophilic lysosomal inclusions, known as zebra bodies or myelin figures in the podocytes. Similar inclusions are also described with drug toxicities, notably hydroxychloroquine (HCQ) toxicity. We report a female in her late 20s with systemic lupus erythematosus (SLE) on HCQ. Renal biopsy showed Class V lupus nephritis with numerous podocytic myelin figures on ultrastructural examination, raising the differential diagnoses of Fabry nephropathy and HCQ toxicity. Enzyme and genetic studies, however, confirmed FD in this patient with SLE. This report highlights a rare dual pathology and discusses possible pathogenetic mechanisms.