#2199 Kidney involvement aspects in women with Fabry disease from the Romanian cohort
Authors: Rusu Elena Emanuela , Jurcut Ruxandra , Ciobotaru Lucia Mihaela , Pandele Gabriel-Robert , Zilisteanu Diana , Blaga Andreea , Balanica Sonia , Gherghiceanu Mihaela , Ismail Gener 
Published: May 2024

Abstract

Background and Aims
Fabry disease (FD) is an X-linked rare lysosomal storage disease causing progressive nervous system, kidney and heart disorders. Progressive kidney impairment is common, and an important cause of morbidity and mortality. In FD females, treatment guidelines recommend therapy initiation when there is evidence of organ involvement, but determining the proper moment to start FD specific treatment could be a real challenge in the cases.
The aim of our retrospective study is to investigate clinical and histological aspects of kidney involvement in female patients with genetically confirmed FD evaluated in our Expert Center for Rare Diseases of the Reno-Urinary System between 2015–2023, with focus on the clinical phenotype and initiation of FD specific treatment.

Method
All patients had comprehensive assessment for target organ manifestations of Fabry disease. Renal function was assessed using serum creatinine, albumin creatinine ratio and proteinuria. Also, 14 (40%) FD females underwent kidney biopsy (KB) in order to reveal the FD specific lesions and/or to establish the indication for FD pathogenic therapy. Kidney biopsy specimens were analyzed by light and electron microscopy.

Results
Our study included 35 heterozygous adult females with FD from 25 unrelated families. Most females (91.4%) were diagnosed through family screening, while 3 females (8.6%) were index cases. The mean age at diagnosis was 43.8 ± 15.3 years (range 17-73 years), although mean age of symptoms onset was 34.3 ± 13.5 years (range 14-61 years).
Six women from our cohort were considered healthy carriers, three females presented only neurological manifestations, nine patients had combined renal and neurological involvement, one patient had cardiac and renal involvement and the others presented multiple organ involvement. Significant co-morbidities were: arterial hypertension in 13 patients, diabetes mellitus in 2 patients, and obesity in 9 patients.
Overall baseline mean eGFR was 79.9 ± 28.2 (range 25-135) ml/min/1.73 m2. Eleven patients had no obvious kidney involvement, 10 patients presented chronic kidney disease (CKD) stage 2, 11 patients CKD stage 3, one CKD stage 4 and 1 was hemodialyzed.
Seventeen patients presented normal UACR, thirteen patients showed microalbuminuria, and four patients presented macroalbuminuria. Overt proteinuria (&gt; 0.3 g/24 h) was noticed in 8 patients.
Thirteen females performed KB before the initiation of FD specific treatment, and one patient was already treated. At the moment of KB, five patients had normal biologic kidney assessment, three patients presented CKD stage 2 (microalbuminuria in 2 cases and proteinuria in 1 case), and five patients presented CKD stage 3 (normoalbuminuria in 1 case, microalbuminuria in 1 case and overt proteinuria in 3 cases). All KBs showed lysosomal accumulation in the podocytes, 92.8% showed inclusions in the parietal cells of the Bowman capsule, 85.7% in the tubules, while vascular inclusions were found in 78.5% of cases. Also, we observed segmental glomerular sclerosis in 5 cases, interstitial fibrosis and tubular atrophy in 3 cases, each.
Only 2 patients were treated with pathogenic therapy before the first evaluation in our center. After multidisciplinary evaluation, 22 patients (62.8%) from our cohort received recommendation to initiate FD specific treatment, and 11 patients entered in our follow-up program. Evidence of specific FD lesions in KB was a strong reason to support the recommendation to initiate FD specific treatment.

Conclusion
Our results showed that kidney involvement in FD females can vary from asymptomatic or mildly symptomatic, to severely symptomatic, with end stage kidney disease. Thus, females should be carefully evaluated and monitored in a multidisciplinary team, in order to diagnosed FD affected organs. Also, we underline that a normal standard assessment of the kidney cannot rule out kidney involvement in female patients with FD, and strengthen the importance of KB for detection of early kidney involvement and for additional support for early initiation of FD specific therapy.