Early Renal Involvement in a Girl with Classic Fabry Disease

Biomarkers for Monitoring Renal Damage Due to Fabry Disease in Patients Treated with Migalastat: A Review for Nephrologists

Nephropathy is a major Fabry disease complication. Kidney biopsies reveal glomerulosclerosis even in pediatric patients. The main manifestations of Fabry nephropathy include reduced glomerular filtration rate and proteinuria. In 2016, an oral pharmacological Chaperone was approved to treat Fabry patients with “amenable” mutations. Because (i) Fabry disease is a rare disorder that frequently causes kidney damage, and (ii) a new therapeutic is currently available, it is necessary to review wich biomarkers are useful for nephropathy follow-up among Fabry “amenable” patients receiving migalastat. The literature search was conducted in MEDLINE, EMBASE, SCOPUS, Cochrane, and Google academic. Prospective studies in which renal biomarkers were the dependent variable or criterion, with at least 6 months of follow-up, were included. Finally, we recorded relevant information in an ad hoc database and summarized the main results. To date, the main useful biomarker for nephropathy monitoring among Fabry “amenable” patients receiving migalastat is glomerular filtration rate estimated by equations that include serum creatinine.

Reduced α-galactosidase A activity in zebrafish (Danio rerio) mirrors distinct features of Fabry nephropathy phenotype

Fabry disease (FD) is a rare genetic lysosomal storage disorder, resulting from partial or complete lack of alpha-galactosidase A (α-GAL) enzyme, leading to systemic accumulation of substrate glycosphingolipids with a broad range of tissue damage. Current in vivo models are laborious, expensive, and fail to adequately mirror the complex FD physiopathology. To address these issues, we developed an innovative FD model in zebrafish. Zebrafish GLA gene encoding α-GAL enzyme presents a high (>70%) homology with its human counterpart, and the corresponding protein has a similar tissue distribution, as evaluated by immunohistochemistry. Moreover, a similar enzymatic activity in different life stages could be demonstrated. By using CRISPR/Cas9 technology, we generated a mutant zebrafish with decreased GLA gene expression, and decreased expression of the specific gene product in the kidney. Mutant animals showed higher plasma creatinine levels and proteinuria. Transmission electron microscopy (TEM) studies documented an increased podocyte foot process width (FPW) in mutant, as compared to wild type zebrafish. This zebrafish model reliably mirrors distinct features of human FD and could be advantageously used for the identification of novel biomarkers and for an effective screening of innovative therapeutic approaches.

Early renal failure in childhood in a male with Fabry disease

Fabry disease is an X-linked lysosomal storage disorder caused by reduced activity or absence of the alpha-galactosidase A enzyme resulting in systemic accumulation of glycosphingolipids. End-stage renal disease (ESRD) is a late-stage manifestation of Fabry disease, typically presenting in the fifth decade of life, but is very rare in childhood. Here we present a case of an 11-year-old boy with classical Fabry disease presenting with ESRD requiring haemodialysis and transplant. Diagnosis was confirmed by renal biopsy, GLA mutation and low alpha-galactosidase A levels. He has an unusual genotype, hemizygous for the c.1000-11T>A intronic variant and positive for the pseudodeficiency allele D313Y. Due to the possibility of very early and accelerated disease progression, Fabry disease should be considered as a possible diagnosis in unexplained renal failure in males from a younger age.

Direct Correlation between Age at Diagnosis and Severity of Nephropathy in Fabry Disease Patients

INTRODUCTION

Nephropathy is one of the major complications of Fabry disease and mainly includes reduced glomerular filtration rate and proteinuria. Affected patients show different degrees of annual loss of renal function according to the magnitude of proteinuria and decrease in estimated glomerular filtration rate (eGFR) at the baseline.

OBJETIVE

To analyze the relationship between age at diagnosis and severity of nephropathy in a Fabry disease population.

METHODS

Cross-sectional design with retrospective data collection.

RESULTS

Seventy-two patients were studied with mean age of 26.26 ± 16.48 years and 30 men (41.6%). Twenty-seven paediatric patients and 45 adults were included. Thirteen genotypes were found: E398X, L415P, c886A>G, L106R, c.680G>A, A292T, c. 448.delG, R363H, C382Y, R301Q, D109G, del 3 and 4 exons, W81X, all pathogenic mutations of GLA gene. The mean eGFR in paediatric population was 115.81 ± 20.87 ml/min/1.73 m2 and in adults was 80.63 ± 42.22 ml/min/1.73 m2. The Pearson's bilateral correlation coefficient test (value = -0.462) between the age at diagnosis and eGFR indicates inverse correlation between both variables with a strong statistical significance (P = < 0.01). Spearman's bilateral correlation coefficient (value = +0.385) between the variables at diagnosis and the degree of proteinuria indicates direct correlation between both variables with a strong statistical significance (P = <0.01).

CONCLUSIONS

Diagnosis of Fabry disease patients at a younger age could be a key to improve the nephropathy prognosis and allow early and effective interventions.

Early initiation of enzyme replacement therapy in classical Fabry disease normalizes biomarkers in clinically asymptomatic pediatric patients

Fabry disease is an X-linked lysosomal storage disorder which often presents with renal, cardiac, gastrointestinal, and nervous system abnormalities. Available enzyme replacement therapies have demonstrated efficacy at significantly reducing elevated biomarkers associated with increased disease activity, while improving the clinical symptoms associated with Fabry disease. In two cases with classical Fabry disease, we demonstrate that the initiation of enzyme replacement therapy prior to the onset of overt clinical disease is well tolerated and effectively reduces elevated biomarkers, mitigating unnecessary organ damage that may occur prior to the onset of clinical manifestations of disease. This proactive approach should be considered as a best-practice management strategy which has the potential to significantly improve health outcomes in patients with classical Fabry patients, particularly in the context of newborn screening for Fabry disease.

Variables Associated with a Urinary MicroRNAs Excretion Profile Indicative of Renal Fibrosis in Fabry Disease Patients

INTRODUCTION

In advanced Fabry nephropathy stages, enzyme replacement theraphy (ERT) efficacy decreases, due to its impossibility to reverse renal fibrosis. Therefore, the finding of early kidney fibrosis biomarkers in affected patients is of interest. During renal fibrosis miR-21, miR-192 and miR-433 (fibrosis promotors) are activated by transforming growth factor-β (TGF-β), and miR-29 and miR-200 family (fibrosis supressors) are inhibited by TGF-β. The aim of this study is to analyze the probability that Fabry disease (FD) patients with some clinical variables can present an urinary microRNAs excretion profile indicative of renal fibrosis through a logistic regression analysis.

RESULTS

A population of 34 participants was included: 24 FD patients and 10 controls. 16/24 (66.66%) FD patients presented microRNAs urinary excretion profile indicative of renal fibrosis. This profile was observed by decrease of fibrosis suppresors miR-29 and miR-200 and not by increase of fibrosis promotors miR-21, miR192, and miR-433. Hypohidrosis, angiokeratomas, neuropathic pain, hearing loss, cardiac involvement, male gender, reduced αGalA activity, and renin-angiotensin-aldosterone system inhibitors treatment are associated with the appearance of amicroRNAs urinary excretion profile indicative of renal fibrosis. A probable beneficial effect on urinary microRNAs excretion profile was observed in patients receiving ERT with agalsidase beta. The correlation between parameters of renal function with each family of microRNAs was studied. The only association with statistical significance was found between miR-21 and urine albumin-creatinine ratio (p =0.021).

CONCLUSIONS

A probable microRNAs regulation not mediated by TGF-β should be considered or TGF-β has a different effect in FD than in other nephropathies on microRNAs regulation. Typical clinical manifestations of classic FD are associated with appearance of urinary microRNAs profile indicative of renal fibrosis. FD patients express renal fibrosis biomarkers in urine prior to onset of pathological albuminuria. A direct correlation between urinary miR-21 and degree of albuminuria was observed.