IgA nephropathy in two adolescent sisters heterozygous for Fabry disease

Endocrinological, immunological and metabolic features of patients with Fabry disease under therapy

OBJECTIVES

Fabry disease is an X-linked lysosomal disorder caused by decreased or absent alpha galactosidase enzyme. The enzyme deficiency leads to progressive accumulation of globotriaosylceramide (Gb-3) and its deacetylated form lyso-Gb3 in various tissue lysosomes that results in primarily lysosomal deterioration and subsequently mitochondrial, endothelial, and immunologic dysfunctions.

METHODS

The endocrinological, metabolic, immunological and HLA status of 12 patients were evaluated.

RESULTS

A total of 11 patients (91.6 %) had immunologic and/or endocrinologic abnormalities. fT4, anti-TPO, and anti-TG levels were increased in 1, 2, and 2 patients, respectively. Three patients had elevated proinflammatory cytokines. ANA profile, p-ANCA and c-ANCA were positive in 1, 1, and 2 patients, respectively. Tissue transglutaminase antibody was negative in all patients however P5 was diagnosed with Celiac disease at the age of 12 and on gluten free diet. All patients had distinct types of HLA apart from 2 patients with anti-TG and anti-TPO positive and there was no relationship between the HLA types and the autoimmunity biomarkers.

CONCLUSIONS

FD may have impact on endocrinologic and immunologic abnormalities even in the patients under ERT, therefore prevalence of these abnormalities may be higher in ERT naïve patients. However, apparently, they are less likely to cause clinical symptoms. Certain HLA alleles may contribute to the direct impact of immunological pathogenesis in FD by developing abnormal autoimmune biomarkers. To the best of our knowledge, this is the first study investigating HLA status of FD patients; therefore further studies are needed to elucidate the underlying mechanism of action.

Urinary complement proteins in IgA nephropathy progression from a relative quantitative proteomic analysis

Aim

IgA nephropathy (IgAN) is one of the leading causes of end-stage renal disease (ESRD). Urine testing is a non-invasive way to track the biomarkers used for measuring renal injury. This study aimed to analyse urinary complement proteins during IgAN progression using quantitative proteomics.

Methods

In the discovery phase, we analysed 22 IgAN patients who were divided into three groups (IgAN 1-3) according to their estimated glomerular filtration rate (eGFR). Eight patients with primary membranous nephropathy (pMN) were used as controls. Isobaric tags for relative and absolute quantitation (iTRAQ) labelling, coupled with liquid chromatography-tandem mass spectrometry, was used to analyse global urinary protein expression. In the validation phase, western blotting and parallel reaction monitoring (PRM) were used to verify the iTRAQ results in an independent cohort (N = 64).

Results

In the discovery phase, 747 proteins were identified in the urine of IgAN and pMN patients. There were different urine protein profiles in IgAN and pMN patients, and the bioinformatics analysis revealed that the complement and coagulation pathways were most activated. We identified a total of 27 urinary complement proteins related to IgAN. The relative abundance of C3, the membrane attack complex (MAC), the complement regulatory proteins of the alternative pathway (AP), and MBL (mannose-binding lectin) and MASP1 (MBL associated serine protease 2) in the lectin pathway (LP) increased during IgAN progression. This was especially true for MAC, which was found to be involved prominently in disease progression. Alpha-N-acetylglucosaminidase (NAGLU) and α-galactosidase A (GLA) were validated by western blot and the results were consistent with the iTRAQ results. Ten proteins were validated in a PRM analysis, and these results were also consistent with the iTRAQ results. Complement factor B (CFB) and complement component C8 alpha chain (C8A) both increased with the progression of IgAN. The combination of CFB and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) also showed potential as a urinary biomarker for monitoring IgAN development.

Conclusion

There were abundant complement components in the urine of IgAN patients, indicating that the activation of AP and LP is involved in IgAN progression. Urinary complement proteins may be used as biomarkers for evaluating IgAN progression in the future.

Screening for Fabry disease in male patients with end-stage renal disease in western France

CONTEXT

Fabry disease is a rare X-linked genetic disease due to pathogenic variants in the GLA gene. Classic Fabry disease is characterized by glycosphingolipids accumulation in all organs including the kidney, resulting in end-stage renal disease in a subset of male patients. Fabry disease should therefore be considered in the differential diagnosis of patients with unexplained end-stage renal disease.

OBJECTIVE

We performed a prospective screening study in Western France to determine the prevalence of Fabry disease in a large population of dialyzed and transplanted patients.

PATIENTS AND METHODS

Patients meeting the inclusion criteria (males, 18-70 years with end-stage renal disease of unknown or vascular origin) were selected from the REIN® registry and the CRISTAL® database. Screening on filter papers was performed after patient consent was obtained during either a dialysis session or a transplantation follow-up visit.

RESULTS

One thousand five hundred and sixty-one end-stage renal disease male patients were screened and 819 consented (dialysis: n=242; transplant: n=577). One single patient was found with decreased alpha-galactosidase levels <25%. GLA sequencing identified the p.Phe113Leu variant in favor of an unknown superimposed kidney disease responsible for end-stage renal disease since this GLA pathogenic variant is associated with a later-onset cardiac form of Fabry disease with minimal kidney involvement. Family cascade genotyping revealed a previously undiagnosed affected brother.

CONCLUSION

The prevalence of Fabry disease in end-stage renal disease patients was 0.12%, questioning the efficacy of this screening strategy with respect to the low prevalence. However, beside the benefit for the patient and his family, the increased awareness of Fabry disease among participating nephrologists may be of interest for future patients.

Screening for Fabry Disease in Patients With Juvenile Systemic Lupus Erythematosus

Objectives

This study aims to determine the prevalence of Fabry disease (FD) among patients with juvenile systemic lupus erythematosus (SLE).

Patients and methods

This cross-sectional study included 76 juvenile SLE patients (12 males; 64 females; mean age 16±3.3 years; range, 8 to 23.5 years) who were diagnosed according to 1997 update of the 1982 American College of Rheumatology revised criteria for classification of SLE. Since the majority of patients were female, alpha-galactosidase A gene was investigated for mutations resulting in FD. Lysosomal accumulation of globotriaosylsphingosine (lyso-Gb3) was further evaluated in mutation positive subjects by using dried blood spot testing.

Results

Alpha-galactosidase A gene screening did not yield any positive mutation in our 74 subjects. However, a heterozygous p.D313Y mutation was found in two females. These subjects were further investigated for lyso-Gb3 levels in dried blood spot samples and the levels of lyso-Gb3 being normal lead to exclusion of FD in these two patients.

Conclusion

We do not suggest routine screening of FD in patients with juvenile SLE; however, prospective studies with larger sample sizes are needed for further analysis.

Fabry disease and immunoglobulin A nephropathy presenting with Alport syndrome-like findings: A case report

RATIONALE

Fabry's disease is an X-linked inherited syndrome. Herein, we presented an unusual case of Fabry disease coexisting with immunoglobulin A nephropathy (IgAN) presenting with Alport syndrome-like pathological findings.

PATIENT CONCERNS

We report a 30-year-old male who presented with proteinuria and elevated serum creatinine and for whom the initial pathologic diagnosis supported Alport syndrome.

DIAGNOSES

A diagnosis of Fabry disease with immunoglobulin A nephropathy (IgAN) was finally made after further examination.

INTERVENTIONS

After the initial diagnosis the patient was treated with herbal medications and mecobalamin.

OUTCOMES

The patient was discharged 1 week later. He was maintained on these treatments and received regular follow-up in our hospital.

LESSONS SUBSECTIONS AS PER STYLE

FD coexisting with IgAN is rare and may have nonspecific clinical presentations. Laboratory examination and genetic diagnosis is needed for confirmation. Timely diagnosis and reproductive intervention is needed for therapy.

Corneal confocal microscopy detects corneal nerve damage and increased dendritic cells in Fabry disease

Fabry disease is characterised by neuropathic pain and accelerated vascular disease. This study evaluates the utility of corneal confocal microscopy (CCM) to non-invasively quantify corneal nerve and endothelial cell morphology and dendritic cell (DC) density in relation to disease severity in subjects with Fabry disease. Seventeen consecutive participants with Fabry disease and 17 healthy control subjects were included in this cross-sectional study. Fabry disease severity was measured using the Mainz Severity Score Index (MSSI). Central corneal sensitivity was assessed with a contact corneal esthesiometer. There was a significant reduction in the corneal sensitivity (5.75 [5.25–6.00] vs. 6.00 [6.00-6.00] cm, P = 0.014), nerve fiber density (NFD) (26.4 ± 10.1 vs. 33.7 ± 7.9 fibers/mm², P = 0.025) and nerve fiber length (NFL) (15.9 ± 3.4 vs. 19.5 ± 4.4 mm/mm², P = 0.012) and an increase in DC density (38.3 [17.5–97.3] vs. 13.5 [0–29.4] cells/mm², P = 0.004) in subjects with Fabry disease compared to the healthy control subjects. The total MSSI score correlated with NFD (ρ = −0.686; P = 0.006), NFL (ρ = −0.692; P = 0.006), endothelial cell density (ρ = −0.511; P = 0.036), endothelial cell area (ρ = 0.514; P = 0.036) and α-galactosidase A enzyme activity (ρ = −0.723; P = 0.008). This study demonstrates reduced corneal sensitivity, corneal nerve fiber damage and increased DCs in subjects with Fabry disease.

Contribution of inflammatory pathways to Fabry disease pathogenesis

Lysosomal storage diseases are usually considered to be pathologies in which the passive deposition of unwanted materials leads to functional changes in lysosomes. Lysosomal deposition of unmetabolized glycolipid substrates stimulates the activation of pathogenic cascades, including immunological processes, and particularly the activation of inflammation. In lysosomal storage diseases, the inflammatory response is continuously being activated because the stimulus cannot be eliminated. Consequently, inflammation becomes a chronic process. Lysosomes play a role in many steps of the immune response. Leukocyte perturbation and over-expression of immune molecules have been reported in Fabry disease. Innate immunity is activated by signals originating from dendritic cells via interactions between toll-like receptors and globotriaosylceramide (Gb3) and/or globotriaosylsphingosine (lyso-Gb3). Evidence indicates that these glycolipids can activate toll-like receptors, thus triggering inflammation and fibrosis cascades. In the kidney, Gb3 deposition is associated with the increased release of transforming growth factor beta and with epithelial-to-mesenchymal cell transition, leading to the over-expression of pro-fibrotic molecules and to renal fibrosis. Interstitial fibrosis is also a typical feature of heart involvement in Fabry disease. Endomyocardial biopsies show infiltration of lymphocytes and macrophages, suggesting a role for inflammation in causing tissue damage. Inflammation is present in all tissues and may be associated with other potentially pathologic processes such as apoptosis, impaired autophagy, and increases in pro-oxidative molecules, which could all contribute synergistically to tissue damage. In Fabry disease, the activation of chronic inflammation over time leads to organ damage. Therefore, enzyme replacement therapy must be started early, before this process becomes irreversible.

Antigen presenting cell abnormalities in the Cln3(-/-) mouse model of juvenile neuronal ceroid lipofuscinosis

Mutations of the CLN3 gene lead to juvenile neuronal ceroid lipofuscinosis (JNCL), an autosomal recessive lysosomal storage disorder that causes progressive neurodegeneration in children and adolescents. There is evidence of immune system involvement in pathology that has been only minimally investigated. We characterized bone marrow stem cell-derived antigen presenting cells (APCs), peritoneal macrophages, and leukocytes from spleen and blood, harvested from the Cln3(-/-) mouse model of JNCL. We detected dramatically elevated CD11c surface levels and increased total CD11c protein in Cln3(-/-) cell samples compared to wild type. This phenotype was specific to APCs and also to a loss of CLN3, as surface levels did not differ from wild type in other leukocyte subtypes nor in cells from two other NCL mouse models. Subcellularly, CD11c was localized to lipid rafts, indicating that perturbation of surface levels is attributable to derangement of raft dynamics, which has previously been shown in Cln3 mutant cells. Interrogation of APC function revealed that Cln3(-/-) cells have increased adhesiveness to CD11c ligands as well as an abnormal secretory pattern that closely mimics what has been previously reported for Cln3 mutant microglia. Our results show that CLN3 deficiency alters APCs, which can be a major contributor to the autoimmune response in JNCL.

Carboxyl-terminal truncations alter the activity of the human α-galactosidase A

Fabry disease is an X-linked inborn error of glycolipid metabolism caused by deficiency of the human lysosomal enzyme, α-galactosidase A (αGal), leading to strokes, myocardial infarctions, and terminal renal failure, often leading to death in the fourth or fifth decade of life. The enzyme is responsible for the hydrolysis of terminal α-galactoside linkages in various glycolipids. Enzyme replacement therapy (ERT) has been approved for the treatment of Fabry disease, but adverse reactions, including immune reactions, make it desirable to generate improved methods for ERT. One approach to circumvent these adverse reactions is the development of derivatives of the enzyme with more activity per mg. It was previously reported that carboxyl-terminal deletions of 2 to 10 amino acids led to increased activity of about 2 to 6-fold. However, this data was qualitative or semi-quantitative and relied on comparison of the amounts of mRNA present in Northern blots with αGal enzyme activity using a transient expression system in COS-1 cells. Here we follow up on this report by constructing and purifying mutant enzymes with deletions of 2, 4, 6, 8, and 10 C-terminal amino acids (Δ2, Δ4, Δ6, Δ8, Δ10) for unambiguous quantitative enzyme assays. The results reported here show that the k_cat/K_m approximately doubles with deletions of 2, 4, 6 and 10 amino acids (0.8 to 1.7-fold effect) while a deletion of 8 amino acids decreases the k_cat/K_m (7.2-fold effect). These results indicate that the mutated enzymes with increased activity constructed here would be expected to have a greater therapeutic effect on a per mg basis, and could therefore reduce the likelihood of adverse infusion related reactions in Fabry patients receiving ERT treatment. These results also illustrate the principle that in vitro mutagenesis can be used to generate αGal derivatives with improved enzyme activity.

Lysosome dysfunction in the pathogenesis of kidney diseases

The lysosome, an organelle central to macromolecule degradation and recycling, plays a pivotal role in normal cell processes, ranging from autophagy to redox regulation. Not surprisingly, lysosomes are an integral part of the renal epithelial molecular machinery that facilitates normal renal physiology. Two inherited diseases that manifest as kidney dysfunction are Fabry's disease and cystinosis, each of which is caused by a primary biochemical defect at the lysosome resulting from loss-of-function mutations in genes that encode lysosomal proteins. The functions of the lysosomes in the kidney and how lysosomal dysfunction might contribute to Fabry's disease and cystinosis are discussed. Unlike most other pediatric renal diseases, therapies are available for Fabry's disease and cystinosis, but require early diagnosis. Recent analysis of ceroid neuronal lipofuscinosis type 3 (Cln3) null mice, a mouse model of lysosomal disease that is primarily associated with neurological deficits, revealed renal functional abnormalities. As current and future therapeutics increase the life-span of those suffering from diseases like neuronal ceroid lipofuscinosis, it remains a distinct possibility that many more lysosomal disorders that primarily manifest as infant and juvenile neurodegenerative diseases may also include renal disease phenotypes.

Coexistence of Fabry disease and IgA nephropathy: a report of two cases

BACKGROUND

Coexistence of Fabry disease and IgA nephropathy is rare. Moreover, the coexisting Fabry disease may be unrecognized due to unapparent clinical manifestations.

METHOD

We described two cases with coexisting Fabry disease and IgA nephropathy. The clinicopathological features of these two patients were studied.

RESULTS

A 54-year-old male presented with proteinuria, hematuria, and hypertension, and a 33-year-old male presented with proteinuria without clinical signs or family history of Fabry disease. Both of them were diagnosed with IgA nephropathy at admission, whereas Fabry disease was not suspected. Subsequent immunofluorescent study confirmed the diagnosis of IgA nephropathy by showing positive staining for IgA and complement C3 in the mesangium. Meanwhile, light microscopy showed remarkable vacuolation of podocytes with mild mesangial expansion, which was characteristic of Fabry nephropathy. Further examination of toluidine blue-stained semi-thin sections and electron microscopy demonstrated blue bodies and myelin figures in the cytoplasm of podocytes, respectively. The diagnosis of coexisting Fabry disease was finally established based on deficient α-galactosidase A activity in both patients.

CONCLUSION

This case study is an important reminder of the role of kidney biopsy as an indicator of Fabry disease and its rare coexistence with IgA nephropathy.

Is there a pathogenic association between Fabry's disease and IgA nephropathy?

Several cases of concurrent Fabry’s disease and IgA nephropathy have been reported, but the pathogenic association between these two diseases remains unclear. This is a report on the case of a girl with severe IgA nephropathy who was subsequently diagnosed with subclinical Fabry’s disease. An 11-year-old girl was admitted to our hospital with massive proteinuria and hematuria detected by urinary screening. An initial renal biopsy revealed severe IgA nephropathy with diffuse mesangial proliferation. She was treated with intravenous methylprednisolone pulses followed by 2 years of oral steroids. The treatment improved both the urinary abnormalities and the second renal biopsy findings. At the age of 15 years, mild proteinuria prompted us to perform a third renal biopsy, and histology revealed minor glomerular abnormalities. In addition, numerous myelin-like bodies were detected in podocytes by electron microscopy. The histological findings combined with the low level of α-galactosidase A activity led to the diagnosis of concomitant Fabry’s disease with IgA nephropathy. Our experience suggests that the initial massive proteinuria was not due to Fabry’s disease, but was rather a manifestation of coincidental IgA nephropathy. We speculate that the coexistence of IgA nephropathy and Fabry’s disease occurred by chance.

The coincidence of IgA nephropathy and Fabry disease

Background

IgA nephropathy (IgAN) is the most common glomerulonephritis, which may also coexist with other diseases. We present two patients with an unusual coincidence of IgAN and Fabry disease (FD).

Case presentation

A 26 year-old man underwent a renal biopsy in February 2001. Histopathology showed very advanced IgAN and vascular changes as a result of hypertension. Because of his progressive renal insufficiency the patient began hemodialysis in August 2001. By means of the blood spot test screening method the diagnosis of FD was suspected. Low activity of alpha-galactosidase A in the patient’s plasma and leukocytes and DNA analysis confirmed the diagnosis of FD. Enzyme replacement therapy started in July 2004. Then the patient underwent kidney transplantation in November 2005. Currently, his actual serum creatinine level is 250 μmol/l. Other organ damages included hypertrophic cardiomyopathy, neuropathic pain and febrile crisis. After enzyme replacement therapy, myocardial hypertrophy has stabilized and other symptoms have disappeared. No further progression of the disease has been noted.

The other patient, a 30 year-old woman, suffered from long-term hematuria with a good renal function. Recently, proteinuria (2.6 g/day) appeared and a renal biopsy was performed. Histopathology showed IgAN with remarkably enlarged podocytes. A combination of IgAN and a high suspicion of FD was diagnosed. Electron microscopy revealed dense deposits in paramesangial areas typical for IgAN and podocytes with inclusive zebra bodies and myelin figures characteristic of FD. FD was confirmed by the decreased alpha-galactosidase A activity in plasma and leukocytes and by DNA and RNA analysis. Enzyme replacement therapy and family screening were initiated.

Conclusions

Our results emphasize the role of complexity in the process of diagnostic evaluation of kidney biopsy samples. Electron microscopy represents an integral part of histopathology, and genetic analysis plays a more and more important role in the final diagnosis, which is followed by causal treatment.

Globotriaosylceramide is correlated with oxidative stress and inflammation in Fabry patients treated with enzyme replacement therapy

Fabry disease is an X-linked inborn error of glycosphingolipid catabolism due to deficient activity of α-galactosidase A that leads to accumulation of the enzyme substrates, mainly globotriaosylceramide (Gb3), in body fluids and lysosomes of many cell types. Some pathophysiology hypotheses are intimately linked to reactive species production and inflammation, but until this moment there is no in vivo study about it. Hence, the aim of this study was to investigate oxidative stress parameters, pro-inflammatory cytokines and Gb3 levels in Fabry patients under treatment with enzyme replacement therapy (ERT) and finally to establish a possible relation between them. We analyzed urine and blood samples of patients under ERT (n=14) and healthy age-matched controls (n=14). Patients presented decreased levels of antioxidant defenses, assessed by reduced glutathione (GSH), glutathione peroxidase (GPx) activity and increased superoxide dismutase/catalase (SOD/CAT) ratio in erythrocytes. Concerning to the damage to biomolecules (lipids and proteins), we found that plasma levels of malondialdehyde (MDA) and protein carbonyl groups and di-tyrosine (di-Tyr) in urine were increased in patients. The pro-inflammatory cytokines IL-6 and TNF-α were also increased in patients. Urinary Gb3 levels were positively correlated with the plasma levels of IL-6, carbonyl groups and MDA. IL-6 levels were directly correlated with di-Tyr and inversely correlated with GPx activity. This data suggest that pro-inflammatory and pro-oxidant states occur, are correlated and seem to be induced by Gb3 in Fabry patients.

Coincidental finding of Fabry's disease in a patient with IgA nephropathy

We present the case of a woman with IgA nephropathy and concomitant Fabry’s disease. She was referred to our hospital with proteinuria and haematuria. A renal biopsy showed findings indicating IgA nephropathy under light and immunofluorescence microscopy. Electron microscopy, however, showed laminated inclusion bodies characteristic of Fabry’s disease. The α-galactosidase activity in her serum was low, and the diagnosis of Fabry’s disease was confirmed by genetic analysis. Fabry’s disease in a patient with IgA nephropathy is a very rare occurrence, and Fabry’s disease diagnosed only by electron microscopy has not been previously reported.

Leukocyte perturbation associated with Fabry disease

Fabry disease is an X-linked lysosomal storage disorder of glycosphingolipid catabolism due to the deficient activity of the enzyme alpha-galactosidase A. The non-degraded substrate, mainly globotriaosylceramide (Galα1-4Galβ1-4Glcβ1-1Cer; Gb(3)) accumulates progressively in the lysosome of various cells. The aim of this work was to analyse changes in leukocyte subpopulations and surface markers and to determine whether Gb(3) is increased in leukocytes of patients with untreated and treated Fabry disease. Blood samples obtained from 22 male Fabry patients (11 untreated and 11 on enzyme replacement therapy) and 22 normal controls were subjected to flow cytometric analysis of Gb(3) intracellular content, leukocyte subpopulations and cell markers. Based on the fluorescence intensity of bound monoclonal antibody, and relative to normal control leukocytes, Gb(3) appeared significantly increased in lymphocytes (but not in monocytes or granulocytes) from patients with Fabry disease. A significantly higher percentage of lymphocytes and CD19(+) cells and a reduced proportion of monocytes, CD8(+) cells and myeloid dendritic cells were detected in samples from Fabry patients compared with normal controls. CD1d expression was significantly lower and MHC class II surface expression was significantly higher in monocytes from Fabry patients than in normal controls. As previously observed for other adhesion molecules, the expression of CD31 (PECAM) was higher in leukocytes from Fabry patients. In conclusion, the differences recorded in this study reveal a leukocyte perturbation associated with the disease state in Fabry patients, whereas some abnormalities are less marked in treated patients.

Kidney biopsy findings in heterozygous Fabry disease females with early nephropathy

Fabry disease is an X-linked glycosphingolipidosis caused by deficiency of alpha-galactosidase. Progressive chronic kidney disease (CKD) is a major cause of morbidity and mortality in males. Although 40% of heterozygous females may develop renal involvement, pathologic data on Fabry nephropathy in heterozygotes are scarce. We reviewed the kidney biopsies of four affected females who had normal to slightly sub-normal renal function, two of them with overt proteinuria. Chronic non-specific degenerative lesions and glycosphingolipid accumulation per cell type were semi-quantitatively assessed by light and electron microscopy. Cellular distribution of glycosphingolipid deposits was best assessed on semithin sections. Podocyte effacement was seen only in proteinuric patients. Combined analysis of our data with those of two earlier series showed that glomerular sclerosis and tubulointerstitial fibrosis are predictors of proteinuria and CKD stage. There was no histopathological evidence supporting a major role of vascular damage in the early pathogenesis of Fabry nephropathy in females.

High incidence of autoantibodies in Fabry disease patients

Fabry disease (FD) is an X-linked disorder of glycosphingolipid catabolism that results from a deficiency of the lysosomal enzyme alpha-galactosidase A. This defect leads to the accumulation of its substrates, mainly globotriaosylceramide, in lysosomes of cells of different tissues. Different studies have shown the involvement of immunopathologies in different sphingolipidoses. The coexistence of FD and immune disorders such as systemic lupus erythematosus, rheumatoid arthritis and IgA nephropathy, has been described in the literature. The aim of this study was to evaluate the prevalence of a group of autoantibodies in a series of Argentine FD patients. Autoantibodies against extractable nuclear antigens (ENAs), double-stranded DNA, anticardiolipin and phosphatidylserine were assayed by ELISA. Lupus anticoagulants were also tested. Fifty-seven per cent of the samples showed reactivity with at least one autoantigen. Such reactivities were more frequent among males than among females. Antiphospholipid autoantibodies were detected in 45% of our patients. The high rate of thrombosis associated with FD could be related, at least in part, to the presence of antiphospholipid autoantibodies in Fabry patients. We found the presence of ENAs, which are a characteristic finding of rheumatological diseases, previous a frequent misdiagnosis of FD, in around 39% of the cases. The detection of a high level of autoantibodies must be correlated clinically to determine the existence of an underlying autoimmune disease. With the recent development of therapy, the life expectancy in FD will increase and autoimmune diseases might play an important role in the morbidity of FD.