Sudden onset of nephrotic syndrome in an asymptomatic Fabry patient: a case report

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disorder caused by the mutation of the GLA gene, encoding the α-galactosidase, which is responsible for the catabolism of neutral glycosphingolipids. Microalbuminuria or low-grade proteinuria, and continuously progressive renal failure are common manifestations in FD males. However, sudden onset of nephrotic syndrome in FD, is rarely reported. CASE REPORT: A 32-year-old Chinese man was admitted to our hospital because of sudden onset of generalized edema due to nephrotic syndrome. He denied hypohidrosis, nocturia, and any history of episodic hand or foot pain. A few scattered angiokeratoma can be found on the low back skin on examination. Except for the similar locating pattern of angiokeratoma, no evident abnormality was found in the laboratory work up and physical examination of his younger brother. The patient was diagnosed with FD companying with minimal change disease by renal biopsy. Genetic analysis on our patient and his sibling revealed a nonsense GLA gene variant (c.707G > A, p.Trp236*), which has been previously reported in FD. Immunotherapy alone (steroids and tacrolimus), but without enzyme replacement therapy, much improved the massive proteinuria. Follow up to date, his 24-h urine protein is stable at about 0.5 g, and renal function keeps normal. CONCLUSION: Sudden onset of nephrotic syndrome, although rare, may occur in FD, even as the primary renal manifestation, but this usually suggests additional renal disease. Immunosuppressive treatment should be considered in such FD patient companying with nephrotic syndrome.