Kidney biopsy findings in heterozygous Fabry disease females with early nephropathy

Fabry disease is an X-linked glycosphingolipidosis caused by deficiency of alpha-galactosidase. Progressive chronic kidney disease (CKD) is a major cause of morbidity and mortality in males. Although 40% of heterozygous females may develop renal involvement, pathologic data on Fabry nephropathy in heterozygotes are scarce. We reviewed the kidney biopsies of four affected females who had normal to slightly sub-normal renal function, two of them with overt proteinuria. Chronic non-specific degenerative lesions and glycosphingolipid accumulation per cell type were semi-quantitatively assessed by light and electron microscopy. Cellular distribution of glycosphingolipid deposits was best assessed on semithin sections. Podocyte effacement was seen only in proteinuric patients. Combined analysis of our data with those of two earlier series showed that glomerular sclerosis and tubulointerstitial fibrosis are predictors of proteinuria and CKD stage. There was no histopathological evidence supporting a major role of vascular damage in the early pathogenesis of Fabry nephropathy in females.