A nationwide cross-sectional analysis of biopsy-proven Fabry nephropathy: the Japan Renal Biopsy Registry

Epidemiology and early predictors of Fabry nephropathy: evaluation of long-term outcomes from a national Fabry centre

BACKGROUND

Fabry disease is a rare genetic lysosomal storage disorder, whereby the accumulation of sphingolipids consequently leads to kidney structural damage and dysfunction. We explored the epidemiology of chronic kidney disease (CKD) among patients with Fabry disease at a major UK referral centre in Greater Manchester serving over 7 million people, to inform early predictors of kidney disease and possible treatment planning.

METHODS

Data were sourced from the electronic records of registered participants from November 2020 to February 2022 of adults diagnosed with Fabry disease, with at least 1 year of follow-up. Four hundred and five participants (female = 223, male = 182) met the initial eligibility criteria. Our study focused on identifying factors linked to incident CKD, with 395 evaluable individuals undergoing outcome analysis over a median of 6.4 years.

RESULTS

Findings concluded that 60.5% of participants received disease-modifying treatments, 29.7% experienced non-fatal cardiovascular events, 3.3% developed end-stage kidney disease (ESKD), and 7.3% died. Men had higher use of disease modifying therapy, progression to ESKD requiring kidney replacement therapy, cardiovascular events, and mortality compared to women. Subgroup analysis over 9 years revealed that older age, cardiovascular history, renin-angiotensin-aldosterone system inhibitor use, and higher urine albumin-to-creatinine ratio (uACR) were predictors of faster estimated glomerular filtration rate (eGFR) decline and increased mortality. At baseline, 47.8% of 249 patients with uACR data had CKD, and 25.4% of the remaining individuals developed CKD during follow-up, associated with higher uACR and lower, albeit normal eGFR levels.

CONCLUSION

Over 60% of Fabry disease patients are at lifetime risk of developing CKD, with a substantial risk of mortality, even with initially normal uACR and eGFR values.

Effects of switching from agalsidase-α to agalsidase-β on biomarkers, renal and cardiac parameters, and disease severity in fabry disease forming neutralizing antidrug antibodies: a case report

Fabry disease is an X-linked hereditary disorder caused by deficient α-galactosidase A (GLA) activity. Patients with Fabry disease are often treated with enzyme replacement therapy (ERT). However, ERT often induces the formation of neutralizing antidrug antibodies (ADAs), which may impair the therapeutic efficacy. Here, we report the case of a 32-year-old man with Fabry disease and resultant neutralizing ADAs who was treated by switching from agalsidase-α to agalsidase-β. We monitored biomarkers, such as plasma globotriaosylsphingosine (lyso-Gb3), urinary globotriaosylceramide (Gb3), urinary mulberry bodies, renal and cardiac parameters, and disease severity during the treatment period. Although plasma lyso-Gb3 and urinary Gb3 levels quickly decreased within two months after the initiation of ERT with agalsidase-α, they gradually increased thereafter. The urinary mulberry bodies continued to appear. Both the ADA titer and serum mediated GLA inhibition rates started to increase after two months. Moreover, 3.5 years after ERT, the vacuolated podocyte area in the renal biopsy decreased slightly from 23.1 to 18.9%. However, plasma lyso-Gb3 levels increased, and urinary Gb3, mulberry body levels, and ADA titers remained high. Therefore, we switched to agalsidase-β which reduced, but did not normalize, plasma lyso-Gb3 levels and stabilized renal and cardiac parameters. Disease severity was attenuated. However, urinary Gb3 and mulberry body levels did not decrease noticeably in the presence of high ADA titers. The kidneys take up a small amount of the administered recombinant enzyme, and the clearance of Gb3 that has accumulated in the kidney may be limited despite the switching from agalsidase-α to agalsidase-β.

A case series of Fabry diseases with CKD in Japan

BACKGROUND

It is well known that kidney injury is vital organ damage in Fabry disease (FD). Renin-angiotensin system (RAS) inhibitors are known to reduce proteinuria in patients with chronic kidney disease (CKD) by dilating the glomerular export arteries and reducing intraglomerular pressure. This improvement in intraglomerular pressure, although lowering the glomerular filtration rate, is thought to prevent renal damage and be renoprotective in the long term. RAS inhibitors may be effective in FD patients with proteinuria to prevent the progression of kidney disease, however, the degree to which they are used in clinical practice is unknown.

METHODS

The J-CKD-DB-Ex is a comprehensive multicenter database that automatically extracts medical data on CKD patients. J-CKD-DB-Ex contains data on 187,398 patients in five medical centers. FD patients were identified by ICD-10. Clinical data and prescriptions of FD patients between January 1 of 2014, and December 31 of 2020 were used for the analysis.

RESULTS

We identified 39 patients with FD from the J-CKD-DB-Ex including those with suspected FD. We confirmed 22 patients as FD. Half of the patients received RAS inhibitors. RAS inhibitors tended to be used in CKD patients with more severe renal impairment.

CONCLUSIONS

This case series revealed the actual clinical practice of FD patients with CKD. In particular, we found cases in which patients had proteinuria, but were not treated with RAS inhibitors. The database was shown to be useful in assessing the clinical patterns of patients with rare diseases.