Abstract: TH-PO619

Renal-Limited Fabry Disease with Negative Genetic Screening

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Chengappa, Madhuri, Mayo clinic, Rochester, Minnesota, United States
  • Mauer, Michael, University of Minnesota, Minneapolis, Minnesota, United States
  • Nasr, Samih H., Mayo Clinic, Rochester, Minnesota, United States
  • Fervenza, Fernando C., Mayo Clinic, Rochester, Minnesota, United States
  • Herrmann, Sandra, Mayo Clinic, Rochester, Minnesota, United States
Background

Fabry disease(FD) is an X-linked lysosomal storage disorder caused by deficient α-galactosidase A(α-GLA) activity. Female carriers disease severity is substantially dependent on random inactivation of X chromosome.

Methods

A 65year old female with history of hypertension was evaluated for lower extremity edema, proteinuria and serum creatinine (SCr) of 1.2mg/dL. Kidney biopsy showed mild mesangial hypercellularity and myelin figures in few podocytes. Genetic testing for FD was negative. No history of supplement use, exposure to silica or amiodarone. Her mother was diagnosed with focal segmental glomerulosclerosis(FSGS) at age 69 and started dialysis 2 years later.
Despite treatment with antihypertensive over 4 years her SCr increased to 1.7 mg/dL. She was referred to Mayo Clinic for further evaluation. On exam she had trace edema, no neuropathy or skin changes and normal ophthalmology evaluation. Proteinuria was 6.1g/24h. Second kidney biopsy showed FSGS pattern of injury, severe hypertensive arteriosclerosis and abundant myelin figures in podocytes(PC). Repeat FD genetic testing was negative. Magnetic resonance cardiac and brain imaging showed no FD features. Serum α-GLA was normal 35(>23.1nmol/h/mg). Urine Globotriaosylceramide(GL3) was 0.019 mg/mmol Creatinine(control <0.030). However urine globotriaosylsphingosine(Lyso-GL3) was elevated at 12.3 ng/mmol Creatinine(Fabry range 0.4-356.6).

Conclusion

This is a case of a renal-limited FD in a female patient apparently superimposed on familial FSGS. Myelin inclusions in some but not all PC is consistent with finding in females with FD. Genetic testing was negative as has been reported in, especially in females. It highlights the importance of measurement of Lyso-GL3/Gb3 in cases where genetic mutation can’t be found.

Abundant myelin figures in podocytes