Screening for fabry disease in patients who underwent renal biopsy and identification of a novel mutation

Abstract

Background: The X-linked Fabry disease (FD) with lysosomal storage of globotriaosylceramide (Gb3) due to α-galactosidase deficiency contributes to nephropathy consisting of proteinuria and renal failure eventually. Early initiation of the enzyme replacement therapy promises favorable renal outcomes. With the importance of early diagnosis, we screened FD among proteinuric patients in whom biopsy findings revealed Fabry nephropathy. Methods: Patients with light microscopic biopsy findings of vacuolated cells, focal and/or segmental glomerular sclerosis, tubular atrophy, and interstitial fibrosis were not associated with particular etiology, the presence of acro-paresthesia, angiokeratomas, and cornea verticillata, stroke history younger than 50 years, family history of renal failure with no cardiovascular risk factors were screened. Fifty-three of 308 consecutive adult patients (45.34 ± 15.23 years old, 60.1% male) who underwent renal biopsy because of proteinuria were enrolled in the study. Screening for FD was performed by assessing α-Gal A activity in dried blood spots (DBS) for males and by genetic testing for females. Results: Fifty-three patients (39.94 ± 11.97 years, 69.8% male) who underwent renal biopsy were screened. Laboratory findings revealed mean serum creatinine of 1.44 ± 1.06 mg/dL, mean estimated glomerular filtration rate of 78.31 ± 39.89 mL/min/1.73 m2, and mean proteinuria of 4.32 ± 3 g/day, whereas the females genetic screening was negative. Two of 37 males had low enzyme activity (<0.1 micmol/L/h) and confirmed FD by genetic analysis in whom one had a novel mutation of GLA gene (c.(1047G>A) p.(Trp349*)). Conclusion: It is worth noting that FD screening in patients with proteinuria, in whom vacuolated cells, mesangial expansion, glomerulosclerosis, interstitial fibrosis, and tubular atrophy of unknown etiology, are present in the renal biopsy either with or without a family history of kidney disease.