Non-Hodgkin lymphoma in a kidney transplanted patient with methylmalonic acidemia: Metabolic susceptibility and the role of immunosuppression

Methylmalonic acidemia cblB type (MMA cblB) is an autosomal recessive inborn error of amino acid metabolism that results in impaired synthesis of adenosylcobalamin, a cofactor of methylmalonyl-CoA mutase. It presents with episodes of coma, vomiting, hypotonia, metabolic acidosis, and hyperammonemia. End-stage kidney disease is a long-term complication. Treatments include vitamin B12 supplementation, L-carnitine, and a low-protein diet. Liver, kidney, or combined liver-kidney transplantations are promising options, but they are not without complications. We report a patient suffering from MMA cblB who developed end-stage kidney disease at 18 years of age. Kidney transplantation allowed him to recover normal kidney function and good metabolic control. Unfortunately, after two decades, he developed non-Hodgkin lymphoma and severe chemotherapy toxicity which led to his death. The risk of lymphoproliferative diseases is known to increase after solid organ transplantation. However, in MMA, factors including mitochondrial dysfunction and oncometabolites, may further increase the risk of malignancy and drug toxicity. Our report highlights the importance of considering the increased risk of cancer in long-term follow-up of MMA cblB patients, especially after solid organ transplantation. Moreover, when chemotherapy is needed, the increased risk of toxicity and metabolic decompensation should be considered and monitored.

Reducing agalsidase beta infusion time in Fabry patients: low incidence of antibody formation and infusion-associated reactions in an Italian multicenter study

BACKGROUND

Fabry disease is a rare progressive X-linked lysosomal storage disease caused by mutations in the GLA gene that encodes α-galactosidase A. Agalsidase beta is a recombinant enzyme replacement therapy authorized in Europe at a standard dose of 1.0 mg/kg intravenously every other week at an initial infusion rate of ≤ 0.25 mg/min until patient tolerance is established, after which the infusion rate may be increased gradually. However, specific practical guidance regarding the progressive reduction in infusion time is lacking. This study investigated a new and specific protocol for reducing agalsidase beta infusion time in which a stable dosage of 15 mg/h is infused for the first four months, and the infusion rate is increased progressively from 15 to 35 mg/h for the subsequent four infusions. The shortest infusion time is reached after six months and maintained thereafter. The incidence of infusion-associated reactions (IARs) and the development of anti-drug antibodies were analyzed, and the disease burden and the clinical evolution of the disease at 12 months were evaluated.

RESULTS

Twenty-five of the 31 patients were naïve to enzyme or chaperone treatment at baseline and six patients had been switched from agalsidase alfa. The reduced infusion time protocol was well tolerated. Only one patient exhibited an IAR, with mild symptoms that resolved with low-dose steroids. Six patients globally seroconverted during treatment (4 with a classic phenotype and 2 with late-onset disease). All but three patients were seronegative at month 12. All patients were stable at the study's end (FAbry STabilization indEX value < 20%); reducing infusion time did not negatively impact clinical outcomes in any patient. The perceived medical assessment showed that the quality of life of all patients improved.

CONCLUSIONS

The study demonstrates that reducing agalsidase beta infusion time is possible and safe from both an immunogenic and clinical point of view. The use of a low infusion rate in the first months when the probability of onset of the development of antibodies is higher contributed to very limited seroconversion to antibody-positive status.

Interpretation of GFR slope in untreated and treated adult Fabry patients

Nephropathy is one of the main features of Fabry disease (FD) that leads, in untreated patients with classical mutations, to end-stage renal disease (ESRD) from the third to the fifth decade of life. The availability of a specific treatment modified the natural history of FD; in particular, it was widely reported that enzyme replacement therapy (ERT) is able to slow the progression of the disease. Regarding Fabry nephropathy, several reports have documented an elevated estimated glomerular filtration rate (eGFR) slope in untreated patients as expression of a rapid disease progression towards ESRD. Otherwise, the prompt start of treatment may be beneficial in stabilizing renal function or slowing its decline. Therefore, based on data in the literature about the effects of ERT on eGFR decline and on the evidence supporting the role of eGFR slope as a surrogate endpoint for chronic kidney disease progression, we suggest, in this 'Expert Opinion', that a treatment should be defined effective when eGFR decline is <1 ml/min/1.73 m2/year and not effective when eGFR loss remains ≥3 ml/min/1.73 m2/year (≥2.5 ml/min/1.73 m2/year in females). Moreover, practical clinical recommendations and guidance for Fabry patients suggests that a change in treatment may be appropriate if individualized therapeutic goals are not achieved. Since a dose-dependent efficacy has been demonstrated for ERT, we suggest considering a switch to a higher dose of ERT in symptomatic adult Fabry patients (ages 18-60 years) with an eGFR of 45-90 ml/min/1.73 m2 and treated with a stable dose of ERT for at least 1 year, in which a linear negative slope of eGFR of 3 ml/min/1.73 m2/year for males (2.5 ml/min/1.73 m2/year for females) was observed.

Effect of Migalastat on cArdiac InvOlvement in FabRry DiseAse: MAIORA study

BACKGROUND

A small but significant reduction in left ventricular (LV) mass after 18 months of migalastat treatment has been reported in Fabry disease (FD). This study aimed to assess the effect of migalastat on FD cardiac involvement, combining LV morphology and tissue characterisation by cardiac magnetic resonance (CMR) with cardiopulmonary exercise testing (CPET).

METHODS

Sixteen treatment-naïve patients with FD (4 women, 46.4±16.2 years) with cardiac involvement (reduced T1 values on CMR and/or LV hypertrophy) underwent ECG, echocardiogram, troponin T and NT-proBNP (N-Terminal prohormone of Brain Natriuretic Peptide) assay, CMR with T1 mapping, and CPET before and after 18 months of migalastat.

RESULTS

No change in LV mass was detected at 18 months compared to baseline (95.2 g/m2 (66.0-184.0) vs 99.0 g/m2 (69.0-121.0), p=0.55). Overall, there was an increase in septal T1 of borderline significance (870.0 ms (848-882) vs 860.0 ms (833.0-875.0), p=0.056). Functional capacity showed an increase in oxygen consumption (VO2) at anaerobic threshold (15.50 mL/kg/min (13.70-21.50) vs 14.50 mL/kg/min (11.70-18.95), p=0.02), and a trend towards an increase in percent predicted peak VO2 (72.0 (63.0-80.0) vs 69.0 (53.0-77.0), p=0.056) was observed. The subset of patients who showed an increase in T1 value and a reduction in LV mass (n=7, 1 female, age 40.5 (28.6-76.0)) was younger and at an earlier disease stage compared to the others, and also exhibited greater improvement in exercise tolerance.

CONCLUSION

In treatment-naïve FD patients with cardiac involvement, 18-month treatment with migalastat stabilised LV mass and was associated with a trend towards an improvement in exercise tolerance. A tendency to T1 increase was detected by CMR. The subset of patients who had significant benefits from the treatment showed an earlier cardiac disease compared to the others.

TRIAL REGISTRATION NUMBER

NCT03838237.

Genome-wide association analyses define pathogenic signaling pathways and prioritize drug targets for IgA nephropathy

IgA nephropathy (IgAN) is a progressive form of kidney disease defined by glomerular deposition of IgA. Here we performed a genome-wide association study of 10,146 kidney-biopsy-diagnosed IgAN cases and 28,751 controls across 17 international cohorts. We defined 30 genome-wide significant risk loci explaining 11% of disease risk. A total of 16 loci were new, including TNFSF4/TNFSF18, REL, CD28, PF4V1, LY86, LYN, ANXA3, TNFSF8/TNFSF15, REEP3, ZMIZ1, OVOL1/RELA, ETS1, IGH, IRF8, TNFRSF13B and FCAR. The risk loci were enriched in gene orthologs causing abnormal IgA levels when genetically manipulated in mice. We also observed a positive genetic correlation between IgAN and serum IgA levels. High polygenic score for IgAN was associated with earlier onset of kidney failure. In a comprehensive functional annotation analysis of candidate causal genes, we observed convergence of biological candidates on a common set of inflammatory signaling pathways and cytokine ligand-receptor pairs, prioritizing potential new drug targets.

An expert consensus on practical clinical recommendations and guidance for patients with classic Fabry disease

Fabry disease is an X-linked inherited lysosomal disorder that causes accumulation of glycosphingolipids in body fluids and tissues, leading to progressive organ damage and reduced life expectancy. It can affect both males and females and can be classified into classic or later-onset phenotypes. In classic Fabry disease, α-galactosidase A (α-Gal A) activity is absent or severely reduced and disease manifestations have an early onset that can affect multiple organs. In contrast, in later-onset Fabry disease, patients have residual α-Gal A activity and clinical features are primarily confined to the heart. Individualized therapeutic goals in Fabry disease are required due to varying phenotypes and patient characteristics, and the wide spectrum of disease severity. An international group of expert physicians convened to discuss and develop practical clinical recommendations for disease- and organ-specific therapeutic goals in Fabry disease, based on expert consensus and evidence identified through a structured literature review. Biomarkers reflecting involvement of various organs in adult patients with classic Fabry disease are discussed and consensus recommendations for disease- and organ-specific therapeutic goals are provided. These consensus recommendations should support the establishment of individualized approaches to the management of patients with classic Fabry disease by considering identification, diagnosis, and initiation of disease-specific therapies before significant organ involvement, as well as routine monitoring, to reduce morbidity, optimize patient care, and improve patient health-related quality of life.

Effect of migalastat on cardiac involvement in Fabry disease: preliminary results from MAIORA study

Background

Fabry Disease (FD) is a rare X-linked lysosomal storage disorder. Since 2016, pharmacological chaperone Migalastat has been approved for treatment of FD patients with amenable mutations to stabilize defective forms of the enzyme α-galactosidase A. A small but significant reduction in left ventricular (LV) mass after 18 months of Migalastat treatment has been previously reported by echocardiography. However, an integrated assessment of the effect of Migalastat on cardiac involvement, combining LV morphology and tissue composition by CMR with exercise capacity by cardiopulmonary test, is lacking.

Purpose

To determine the effects of 18 month treatment with Migalastat on LV mass, native T1 value and functional capacity in naïve patients with genetically confirmed FD cardiomyopathy.

Methods

Sixteen treatment naïve FD patients (4 females, mean age 46.4±16.2) with amenable mutations and signs of cardiac involvement underwent CMR with T1 mapping and cardio-pulmonary testing before and after 18 months of migalastat therapy as a part of MAIORA Study. Cardiac involvement was defined as presence of reduced native T1 values at CMR (a surrogate of myocardial glycosphingolipid storage) and/or LV hypertrophy (LVH). Nine patients (56%, 2 females, mean age 56.4±12.7 years) had LVH at baseline.

Results

Migalastat treatment was well tolerated in all patients, with no serious adverse event. No change in LV mass was detected at 18 months compared to baseline (95.2 (66.0–184.0) vs 103.0 (71.0–182.0) g/m2; p=0.5516). The same result was found after stratifying patients according to presence/absence of Late Gadolinium Enhancement (LGE) (LGE+ n=8, 2 females, mean age 56.2±13.1 years). There was a trend towards an increased native septal T1 value (870.0 (848–882) vs 860.0 (833.0–875.0) ms at baseline; p 0.056) with unchanged extracellular volume (ECV) (0.26 (0.23–0.028) vs 0.26 (0.22–0.29) at baseline; p 0.276) in the overall cohort. An improvement in functional capacity with a trend towards an increase in percent-predicted peak VO2 (72.0 (61.25–80.75) vs 67.0 (45.2–79.2) at baseline; p 0.056) and a significant increase in VO2 at anaerobic threshold (14.8 (12.6–20.0) vs 13.10 (6.8–18.6) ml/kg/min at baseline; p 0.004) was reported in the total population.

Conclusion

In treatment naïve FD patients with amenable mutations and signs of early or overt cardiac involvement, 18-month treatment with Migalastat stabilized LV mass both in patients with and without LGE and was associated with an improvement in exercise tolerance. The trend towards an increase in T1 value associated with unchanged ECV suggests partial clearance of cardiomyocyte glycoshingolipid storage. These real-world data are consistent with a beneficial impact of migalastat on the progression of cardiac involvement in FD.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Amicus Therapeutics

ECG-based score estimates the probability to detect Fabry Disease cardiac involvement

OBJECTIVES

To elaborate an ECG-based nomogram estimating the probability to detect cardiac involvement by cardiac magnetic resonance (CMR) in Fabry Disease (FD).

METHODS

119 FD patients and 26 healthy controls underwent ECG and CMR. Test (n = 88, 60%) and validation cohorts (n = 57, 40%) were randomly derived. Cardiac involvement was defined as the presence of low myocardial T1 value, a CMR-surrogate of myocardial glycosphingolipid storage. ECG changes associated with low T1 value were identified in the test cohort, included in the nomogram and then tested in the validation cohort.

RESULTS

Sokolow-Lyon index (AUC = 0.769), ratio between P-wave and PR-segment durations (Pwave/PRsegment) (AUC = 0.778), QRS duration (AUC = 0.703), QT (AUC = 0.769) duration were independently associated with the presence of low T1 on CMR at multivariate analysis. An ECG-based nomogram including these four parameters was accurate in identifying patients with CMR evidence of glycosphingolipid storage (c-index of the derived-nomogram = 0.90 in the test group; 0.81 in the validation group).

CONCLUSION

We propose a practical ECG-based nomogram accurately estimating the probability to detect low T1 values by CMR in FD patients. The application of this tool in clinical practice could improve early detection of FD cardiac involvement.

Multicenter evaluation of use of dried blood spot compared to conventional plasma in measurements of globotriaosylsphingosine (LysoGb3) concentration in 104 Fabry patients

OBJECTIVES

Fabry disease (FD) is an X-linked lysosomal storage disorder, resulting from a deficiency of the enzyme α-galactosidase A, responsible for breaking down glycolipids such as globotriaosylceramide and its deacylated derivative, globotriaosylsphingosine (LysoGb3). Here, we compare the levels of LysoGb3 in dried blood spots (DBS) and plasma in patients with classic and late-onset phenotypes.

METHODS

LysoGb3 measurements were performed in 104 FD patients, 39 males and 65 females. Venous blood was collected. A portion was spotted onto filter paper and another portion separated to obtain plasma. The LysoGb3 concentrations in DBS and plasma were determined by highly sensitive electrospray ionization liquid chromatography tandem mass spectrometry. Agreement between different matrices was assessed using linear regression and Bland Altman analysis.

RESULTS

The method on DBS was validated by evaluating its precision, accuracy, matrix effect, recovery, and stability. The analytical performances were verified by comparison of a total of 104 paired DBS and plasma samples from as many FD patients (representing 46 GLA variants). There was a strong correlation between plasma and the corresponding DBS LysoGb3 concentrations, with few exceptions. Discrepancies were observed in anemic patients with typically low hematocrit levels compared to the normal range.

CONCLUSIONS

The method proved to be efficient for the rapid analysis of LysoGb3. DBS provides a convenient, sensitive, and reproducible method for measuring LysoGb3 levels for diagnosis, initial phenotypic assignment, and therapeutic monitoring in patients with FD.

Nutrition in adult patients with selected lysosomal storage diseases

Lysosomal storage disorders (LSDs) are a group of clinically heterogeneous disorders affecting the function of lysosomes and are characterized by an accumulation of undigested substrates within several cell types. In recent years there have been substantial advances in supportive care and drug treatment for some LSDs, leading to improved patient survival, as seen in Gaucher, Pompe and Fabry disease and some Mucopolysaccharidoses; however, many symptoms still persist. Thus it is now even more important to improve patients' quality of life and reduce symptoms and comorbidities. One potential way of achieving this goal is through adjunct nutritional therapy, which is challenging as patients may be overweight with associated consequences, or malnourished, or underweight. Furthermore, drugs used to treat LSDs can modify the metabolic status and needs of patients. There are currently not enough data to make specific dietary recommendations for individual LSDs; however, suggestions can be made for managing clinical manifestations of the diseases, as well as treatment-associated adverse events. The metabolic and nutritional status of adult patients must be regularly assessed and individualized dietary plans may be created to cater to a patient's specific needs. Damage to the autophagic process is a common feature in LSDs that is potentially sensitive to dietary manipulation and needs to be assessed in clinical studies.

Trabecular complexity as an early marker of cardiac involvement in Fabry disease

AIMS

Fabry cardiomyopathy is characterized by glycosphingolipid storage and increased myocardial trabeculation has also been demonstrated. This study aimed to explore by cardiac magnetic resonance whether myocardial trabecular complexity, quantified by endocardial border fractal analysis, tracks phenotype evolution in Fabry cardiomyopathy.

METHODS AND RESULTS

Study population included 20 healthy controls (12 males, age 32±9) and 45 Fabry patients divided into three groups: 15 left ventricular hypertrophy (LVH)-negative patients with normal T1 (5 males, age 28±13; Group 1); 15 LVH-negative patients with low T1 (9 males, age 33±9.6; Group 2); 15 LVH-positive patients (11 males, age 53.5±9.6; Group 3). Trabecular fractal dimensions (Dfs) (total, basal, mid-ventricular, and apical) were evaluated on cine images. Total Df was higher in all Fabry groups compared to controls, gradually increasing from controls to Group 3 (1.27±0.02 controls vs. 1.29±0.02 Group 1 vs. 1.30±0.02 Group 2 vs. 1.34±0.02 Group 3; P<0.001). Group 3 showed significantly higher values of all Dfs compared to the other Groups. Both basal and total Dfs were significantly higher in Group 1 compared with controls (basal: 1.30±0.03 vs. 1.26±0.04, P =0.010; total: 1.29±0.02 vs. 1.27±0.02, P=0.044). Total Df showed significant correlations with: (i) T1 value (r=-0.569; P<0.001); (ii) LV mass (r=0.664, P<0.001); (iii) trabecular mass (r=0.676; P <0.001); (iv) Mainz Severity Score Index (r=0.638; P<0.001).

CONCLUSION

Fabry cardiomyopathy is characterized by a progressive increase in Df of endocardial trabeculae together with shortening of T1 values. Myocardial trabeculation is increased before the presence of detectable sphingolipid storage, thus representing an early sign of cardiac involvement.

Deficiency in the Screening Process of Fabry Disease: Analysis of Chronic Kidney Patients Not on Dialysis

Fabry Disease (FD), a rare and progressive, X-linked lysosomal storage disorder, is caused by mutations in the α-galactosidase A (GLA) gene which leads to enzymatic deficiency of GLA. Misdiagnosed and undiagnosed FD cases are common for the variable FD phenotype, ranging from asymptomatic and/or impairment of single organs, which is typically seen in females and in patients with late-onset mutation, to multiple organ disease, which is frequently found in males with classic GLA mutation. Consequently, for an early diagnosis and an efficient treatment of FD, three different strategies of screening, new-born screening, high-risk screening and familiar screening, have been conducted. However, most of FD screening in the CKD population has been carried out in hemodialysis patients and kidney transplant recipients, for whom the renal damage is already irreversible, so the effectiveness of enzymatic replacement therapy is limited and delayed therapeutic intervention results in worse long-term outcomes. This review investigates the actual strategies of screening initiatives for the identification of FD, examining in detail those performed in CKD patients not on dialysis.

Progressive electrocardiographic changes in parallel with cardiac magnetic resonance findings in fabry disease

Background

Cardiac Magnetic Resonance (CMR) allows to detect progressive stages of cardiac involvement in Fabry Disease (FD). A systematic description of electrocardiographic (ECG) alterations occurring in FD is currently missing.

Purpose

To explore ECG changes in progressive stages of FD cardiomyopathy.

Methods

71 FD patients and 17 healthy controls underwent CMR with T1 mapping and 12-lead ECG. ECG analysis included the duration of the P-wave and the interval between the end of P-wave and the beginning of QRS (PendQ). FD patients in the test cohort were divided into 3 groups with increasing severity of cardiac involvement: A) normal T1, no LVH; B) low T1, no LVH; C) low T1, LVH.

Results

An increase of Pwave/PendQ ratio was observed in Group A compared to Controls (1.08 vs. 0.75, p&lt;0.0001). Higher Pwave/PendQ ratio (1.50 vs. 1.08, p&lt;0.0001), shorter PQc interval (127.9 vs. 159.5, p=0.0007), increased Sokolow-Lyon Index (SLI) (3.2 vs. 2.4, p&lt;0,001) and T wave amplitude (0.6 vs. 0.4 mV, p=0.002) characterized Group B in comparison with Group A. A higher prevalence of left bundle branch blocks (13.6% vs. 0%, p=0.03) and repolarization abnormalities (77.3% vs. 5.7%), wider QRS (120 vs 95 msec, p&lt;0.0001) and QT (460 vs 400 msec, p=0.003) intervals were found in Group C compared to Group B. SLI (AUC 0.769), Pwave/PendQ (AUC 0.778), QRS (AUC 0.703) and QT (AUC 0.769) durations resulted to be independent predictors of low T1 values on CMR at stepwise multivariate analysis.

Conclusion

FD is characterized by progressive ECG changes. The identification of ECG parameters able to predict a lowering of myocardial T1 values on CMR may promote early detection of cardiac involvement, helping to target the therapeutic approach.

Progressive ECG and CMR changes in FD

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): This study was partially supported by Ricerca Corrente funding from the Italian Ministry of Health to IRCCS Policlinico San Donato.

Predictors of Clinical Evolution in Prehypertrophic Fabry Disease

BACKGROUND

In prehypertrophic Fabry disease, low myocardial T1 values, reflecting sphingolipid storage, are associated with early structural and ECG changes. The correlations between T1 values and functional parameters have not been explored. Furthermore, the potential prognostic role of T1 in predicting disease worsening is still unknown.

METHODS

ECG, 2D echocardiography, cardiopulmonary test, and cardiac magnetic resonance were performed in 44 Fabry patients without left ventricular hypertrophy (35.7±14.5 years, 68.2% females). After a 12-month follow-up, clinical stability was evaluated using Fabry Stabilization Index.

RESULTS

At baseline, T1 values showed a negative correlation with left ventricular mass ( r=-0.79; P<0.0001), maximum wall thickness ( r=-0.79; P<0.0001), Sokolow-Lyon Index ( r=-0.54; P<0.0001), left atrial volume ( r=-0.49; P<0.0002), and Mainz Severity Score Index ( r=-0.61; P<0.0001). No significant differences in systo-diastolic function and exercise capacity were observed comparing normal and low T1 Fabry patients. Arrhythmias were reported in 2 females with low T1 and late gadolinium enhancement. Five patients (40.0±12.4 years, 2 females) showed clinical worsening (Fabry Stabilization Index >20%) at follow-up. Higher left ventricular wall thickness (odds ratio, 2.61; CI, 1.04-6.57; P=0.04), left atrial volume (odds ratio, 1.24; CI, 1.02-1.51; P=0.03), and lower T1 values (odds ratio, 0.98; CI, 0.96-0.99; P=0.03) at baseline were independently associated with clinical worsening at follow-up.

CONCLUSIONS

In prehypertrophic Fabry disease, low T1 values correlate with early electrocardiographic, morphological cardiac changes, and worsening of global disease severity but are not associated with functional abnormalities. The presence of low T1 values is a risk factor for disease worsening, thus representing a potential new tool in prognostic stratification and therapeutic approach.

TRPP2 dysfunction decreases ATP-evoked calcium, induces cell aggregation and stimulates proliferation in T lymphocytes

Background

Autosomal dominant polycystic kidney disease (ADPKD) is mainly characterised by the development and enlargement of renal cysts that lead to end-stage renal disease (ESRD) in adult patients. Other clinical manifestations of this pathology include hypertension, haematuria, abdominal pain, cardiovascular system alterations and intracranial aneurysms. ADPKD is linked to mutations in either PKD1 or PKD2 that codifies polycystin-1 (PC1) and polycystin-2 (PC2 or TRPP2), respectively. PC1 and TRPP2 are membrane proteins that function as receptor-channel elements able to regulate calcium homeostasis. The function of polycystins has been mainly studied in kidney cells; but the role of these proteins in T lymphocytes is not well defined.

Methods

T lymphocytes were produced from ADPKD1 and ADPKD2 patients as well as from non-ADPKD subjects undergoing renal replacement therapy (RRT) and healthy controls. Protein expression and phosphorylation levels were analysed by western blotting, cell proliferation was calculated by direct counting using trypan blue assay and intracellular calcium concentration was measured by Fura-2 method.

Results

PKD2 mutations lead to the significant reduction of TRPP2 expression in T lymphocytes derived from ADPKD patients. Furthermore, a smaller TRPP2 truncated protein in T lymphocytes of patients carrying the mutation R872X in PKD2 was also observed, suggesting that TRPP2 mutated proteins may be stably expressed. The silencing or mutation of PKD2 causes a strong reduction of ATP-evoked calcium in Jurkat cells and ADPKD2 T lymphocytes, respectively. Moreover, T lymphocytes derived from both ADPKD1 and ADPKD2 patients show increased cell proliferation, basal chemotaxis and cell aggregation compared with T lymphocytes from non-ADPKD subjects. Similarly to observations made in kidney cells, mutations in PKD1 and PKD2 dysregulate ERK, mTOR, NFkB and MIF pathways in T lymphocytes.

Conclusions

Because the alteration of ERK, mTOR, NFkB and MIF signalling found in T lymphocytes of ADPKD patients may contribute to the development of interstitial inflammation promoting cyst growth and kidney failure (ESRD), the targeting of inflammasome proteins could be an intriguing option to delay the progression of ADPKD.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1540-6) contains supplementary material, which is available to authorized users.

Parapelvic cysts, a distinguishing feature of renal Fabry disease

Background

Fabry's disease (FD) is a rare, multi-organ lysosomal disease, caused by the deficiency of the enzyme α-galactosidase A, and is difficult to diagnose. Although parapelvic cysts (PC) were previously associated with FD, their prevalence and significance are unclear.

Methods

The present study aimed to: (i) evaluate, by renal ultrasound, the real prevalence of PC and of their determinants in a multicentre, nationwide cohort of FD patients (n = 173, Study 1) and (ii) ascertain whether a greater accuracy of PC detection improved their identification, in FD patients from a single centre (n = 67, Study 2). In both studies, for each FD patient, an age- and renal function-matched subject was selected for comparison (1:1).

Results

In Study 1, PC were detected in 28.9% of FD subjects and in only 1.1% of control subjects (P < 0.001). The presence of other renal abnormalities did not differ between the groups, nor differences exist in the main demographic and laboratory parameters between the groups. In Study 2, the greater accuracy of ultrasound increased PC prevalence from 29.8% to 43.3% in the same subjects (P < 0.05). In both studies, no correlation was detected between PC and the main demographic, clinical and biochemical parameters, including use of enzyme replacement therapy (P < 0.1, minimum value). Finally, no difference existed between FD patients with and without PC.

Conclusions

The present study suggests that the presence of PC in renal patients should alert physicians to consider the diagnosis of FD, primarily in subjects with an unclear family history of renal disease and in the presence of other stigmata of the disease.

[The Fabry nephropathy: new insight in diagnosis, monitoring and treatment]

Fabry disease is a rare inborn error of the enzyme α-galactosidase (Α-Gal) and results in lysosomal substrate accumulation in tissues with a wide range of clinical presentations. The disease has attracted a lot of interest over the last years and several issues has been discovered up to now leading to increasing knowledge and awareness of the disease. However, several aspects are still unclear and under investigation. Thus, the new challenges that physicians encounter are the discovering of the pathogenic mechanisms, the neutralising antibodies to ERT, the long-term efficacy of therapies. In this article, we summarise and review the latest developments in the science community regarding diagnosis, management and monitoring of Fabry disease concerning in particular its physiopathology, novel biomarkers, antibodies development and novel treatment options.

The effect of enzyme replacement therapy on clinical outcomes in male patients with Fabry disease: A systematic literature review by a European panel of experts

Background

Enzyme replacement therapy (ERT) with recombinant human α-galactosidase has been available for the treatment of Fabry disease since 2001 in Europe and 2003 in the USA. Treatment outcomes with ERT are dependent on baseline patient characteristics, and published data are derived from heterogeneous study populations.

Methods

We conducted a comprehensive systematic literature review of all original articles on ERT in the treatment of Fabry disease published up until January 2017. This article presents the findings in adult male patients.

Results

Clinical evidence for the efficacy of ERT in adult male patients was available from 166 publications including 36 clinical trial publications. ERT significantly decreases globotriaosylceramide levels in plasma, urine, and in different kidney, heart, and skin cell types, slows the decline in estimated glomerular filtration rate, and reduces/stabilizes left ventricular mass and cardiac wall thickness. ERT also improves nervous system, gastrointestinal, pain, and quality of life outcomes.

Conclusions

ERT is a disease-specific treatment for patients with Fabry disease that may provide clinical benefits on several outcomes and organ systems. Better outcomes may be observed when treatment is started at an early age prior to the development of organ damage such as chronic kidney disease or cardiac fibrosis. Consolidated evidence suggests a dose effect. Data described in male patients, together with female and paediatric data, informs clinical practice and therapeutic goals for individualized treatment.

New insights from the application of the FAbry STabilization indEX in a large population of Fabry cases

Background

The FAbry STabilization indEX (FASTEX) is an innovative index allowing the assessment of clinical stability over time in Fabry disease patients. This index was developed in a population of 28 male patients with the classical form of Fabry disease.

Objectives

The aim of the study was to test the accuracy of the FASTEX in evaluating Fabry disease stability in 132 male and female patients with classical and non-classical Fabry disease from nine Italian centres and it also aimed to define the sensitivity and specificity of this new tool. In particular, we aimed to investigate the correlation between the FASTEX and clinical judgement in a large-scale cohort of the study population.

Methods

Statistical methods applied to this investigation included the calculation of accuracy, specificity and sensitivity, receiver operating characteristic (ROC) curves and Cohen's κ index related to the FASTEX and clinical judgement.

Results

The patient population included 58 males (43.9%). The mean age of the overall population was 46.3 ± 15. 1 years (range 31.2-61.4). The median interval between the two multidisciplinary evaluations used for FASTEX calculation was 398 days. Since no gold standard method is available to define the overall clinical condition of Fabry patients over time, the results of the FASTEX were compared with clinical judgements given by the physicians involved in this study. In this way, the FASTEX classified 121 of 132 (92%) patients correctly. In particular, the FASTEX correctly identified 93% (41/44) of clinically 'unstable' and 91% (80/88) of clinically 'stable' patients. The area under the curve of the ROC related to the FASTEX index cut-off (20) was equal to 0.967, very close to its theoretical maximum (1), which means that it is an excellent test for classifying patients as 'stable' or 'unstable' compared with clinical judgement. In addition, the FASTEX cut-off >20 provides the most acceptable balance between sensitivity and specificity. The Cohen's κ index value obtained in our study was 0.82, showing a highly statistically significant P-value < 0.01 related to the agreement between the FASTEX and clinical judgement.

Conclusions

The FASTEX is demonstrated here to be a specific and sensitive tool. When applied to a large cohort of Fabry patients, it was shown to be a valid instrument in helping physicians to discriminate objectively the clinical stability of individual Fabry patients.

European expert consensus statement on therapeutic goals in Fabry disease

BACKGROUND

Fabry disease, an inherited lysosomal storage disorder, causes multi-organ pathology resulting in substantial morbidity and a reduced life expectancy. Although Fabry disease is an X-linked disorder, both genders may be affected, but generally to a lesser extent in females. The disease spectrum ranges from classic early-onset disease to non-classic later-onset phenotypes, with complications occurring in multiple organs or being confined to a single organ system depending on the stage of the disease. The impact of therapy depends upon patient- and disease-specific factors and timing of initiation.

METHODS

A European panel of experts collaborated to develop a set of organ-specific therapeutic goals for Fabry disease, based on evidence identified in a recent systematic literature review and consensus opinion.

RESULTS

A series of organ-specific treatment goals were developed. For each organ system, optimal treatment strategies accounted for inter-patient differences in disease severity, natural history, and treatment responses as well as the negative burden of therapy and the importance of multidisciplinary care. The consensus therapeutic goals and proposed patient management algorithm take into account the need for early disease-specific therapy to delay or slow the progression of disease as well as non-specific adjunctive therapies that prevent or treat the effects of organ damage on quality of life and long-term prognosis.

CONCLUSIONS

These consensus recommendations help advance Fabry disease management by considering the balance between anticipated clinical benefits and potential therapy-related challenges in order to facilitate individualized treatment, optimize patient care and improve quality of life.

Redefining the Pulvinar Sign in Fabry Disease

BACKGROUND AND PURPOSE

The pulvinar sign refers to exclusive T1WI hyperintensity of the lateral pulvinar. Long considered a common sign of Fabry disease, the pulvinar sign has been reported in many pathologic conditions. The exact incidence of the pulvinar sign has never been tested in representative cohorts of patients with Fabry disease. The aim of this study was to assess the prevalence of the pulvinar sign in Fabry disease by analyzing T1WI in a large Fabry disease cohort, determining whether relaxometry changes could be detected in this region independent of the pulvinar sign positivity.

MATERIALS AND METHODS

We retrospectively analyzed brain MR imaging of 133 patients with Fabry disease recruited through specialized care clinics. A subgroup of 26 patients underwent a scan including 2 FLASH sequences for relaxometry that were compared with MRI scans of 34 healthy controls.

RESULTS

The pulvinar sign was detected in 4 of 133 patients with Fabry disease (3.0%). These 4 subjects were all adult men (4 of 53, 7.5% of the entire male population) with renal failure and under enzyme replacement therapy. When we tested for discrepancies between Fabry disease and healthy controls in quantitative susceptibility mapping and relaxometry maps, no significant difference emerged for any of the tested variables.

CONCLUSIONS

The pulvinar sign has a significantly lower incidence in Fabry disease than previously described. This finding, coupled with a lack of significant differences in quantitative MR imaging, allows hypothesizing that selective involvement of the pulvinar is a rare neuroradiologic sign of Fabry disease.

Different renal phenotypes in related adult males with Fabry disease with the same classic genotype

Background

Fabry disease related patients with classical mutation usually exhibit similar severe phenotype especially concerning renal manifestation.

Methods

A dry blood spot screening (DBS) and the DNA analysis has been performed in a 48‐year‐old man (Patient 1) because of paresthesia.

Results

The DBS revealed absent leukocyte α‐Gal A enzyme activity while DNA analysis identified the I354K mutation. Serum creatinine and e‐GFR were in normal range and also albuminuria and proteinuria were absent. The brain MRI showed ischemic lesions and a diffuse focus of gliosis in the white matter, while the echocardiogram showed a left ventricular hypertrophy. The renal biopsy performed in the case index showed a massive deposition of zebra bodies. By a familiar investigation, it was recognized that his brother (Patient 2) died 2 years before from sudden death syndrome at the age of 49. He had suffered sporadic and undiagnosed pain at the extremities, a prior cataract, bilateral neurosensorial hearing loss and left ventricular hypertrophy on Echocardiogram. His previous laboratory examinations revealed a normal serum creatinine and the absence of proteinuria. Pedigree analysis of the brothers revealed a high disease burden among family members, with an affected cousin (Patient 3) who progressed early to end‐stage renal disease (ESRD) that required renal transplantation.

Conclusions

Here we describe the clinical history of three adult male members of the same family with the same genotype who manifested different presentation and progression of the disease, particularly concerning the renal involvement.

Comparison of Total Kidney Volume Quantification Methods in Autosomal Dominant Polycystic Disease for a Comprehensive Disease Assessment

BACKGROUND

In recent times, the scientific community has been showing increasing interest in the treatments aimed at slowing the progression of the autosomal dominant polycystic kidney disease (ADPKD). Therefore, in this paper, we test and evaluate the performance of several available methods for total kidney volume (TKV) computation in ADPKD patients - from echography to MRI - in order to optimize patient classification.

METHODS

Two methods based on geometric assumptions (mid-slice [MS], ellipsoid [EL]) and a third one on true contour detection were tested on 40 ADPKD patients at different disease stage using MRI. The EL method was also tested using ultrasound images in a subset of 14 patients. Their performance was compared against TKVs derived from reference manual segmentation of MR images. Patient clinical classification was also performed based on computed volumes.

RESULTS

Kidney volumes derived from echography significantly underestimated reference volumes. Geometric-based methods applied to MR images had similar acceptable results. The highly automated method showed better performance. Volume assessment was accurate and reproducible. Importantly, classification resulted in 79, 13, 10, and 2.5% of misclassification using kidney volumes obtained from echo and MRI applying the EL, the MS and the highly automated method respectively.

CONCLUSION

Considering the fact that the image-based technique is the only approach providing a 3D patient-specific kidney model and allowing further analysis including cyst volume computation and monitoring disease progression, we suggest that geometric assumption (e.g., EL method) should be avoided. The contour-detection approach should be used for a reproducible and precise morphologic classification of the renal volume of ADPKD patients.

Screening, diagnosis, and management of patients with Fabry disease: conclusions from a "Kidney Disease: Improving Global Outcomes" (KDIGO) Controversies Conference

Patients with Fabry disease (FD) are at a high risk for developing chronic kidney disease and cardiovascular disease. The availability of specific but costly therapy has elevated the profile of this rare condition. This KDIGO conference addressed controversial areas in the diagnosis, screening, and management of FD, and included enzyme replacement therapy and nonspecific standard-of-care therapy for the various manifestations of FD. Despite marked advances in patient care and improved overall outlook, there is a need to better understand the pathogenesis of this glycosphingolipidosis and to determine the appropriate age to initiate therapy in all types of patients. The need to develop more effective specific therapies was also emphasized.

FAbry STabilization indEX (FASTEX): an innovative tool for the assessment of clinical stabilization in Fabry disease

Two disease severity scoring systems, the Mainz Severity Score Index (MSSI) and Fabry Disease Severity Scoring System (DS3), have been validated for quantifying the disease burden of Fabry disease. We aimed to develop a dynamic mathematical model [the FASTEX (FAbry STabilization indEX)] to assess the clinical stability. A multidisciplinary panel of experts in Fabry disease first defined a novel score of severity [raw score (RS)] based on three domains with a small number items in each domain (nervous system domain: pain, cerebrovascular events; renal domain: proteinuria, glomerular filtration rate; cardiac domain: echocardiography parameters, electrocardiograph parameters and New York Heart Association class) and evaluated the clinical stability over time. The RS was tested in 28 patients (15 males, 13 females) with the classic form of Fabry disease. There was good statistical correlation between the newly established RS and a weighted score (WS), with DS3 and MSSI (R² = 0.914, 0.949, 0.910 and 0.938, respectively). In order to refine the RS further, a WS, which was expressed as a percentage value, was calculated. This was based on the relative clinical significance of each item within the domain with the panel agreeing on the attribution of a different weight of clinical damage to a specific organ system. To test the variation of the clinical burden over time, the RS was repeated after 1 year. The panel agreed on a cut-off of a 20% change from baseline as the clinical WS to define clinical stability. The FASTEX model showed good correlation with the clinical assessment and with clinical variation over time in all patients.

Early markers of Fabry disease revealed by proteomics

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by a deficiency of the lysosomal hydrolase α-galactosidase A (α-GalA) that leads to the intra-lysosomal accumulation of globotriaosylceramide (Gb3) in various organ systems. As a consequence, a multisystems disorder develops, culminating in stroke, progressive renal and cardiac dysfunction. Enzyme replacement therapy (ERT) offers a specific treatment for patients affected by FD, though the monitoring of treatment is hindered by a lack of surrogate markers of response. Remarkably, due to the high heterogeneity of the Fabry phenotype, both diagnostic testing and treatment decisions are more challenging in females than in males; thus, reliable biomarkers for Fabry disease are needed, particularly for female patients. Here, we use a proteomic approach for the identification of disease-associated markers that can be used for the early diagnosis of FD as well as for monitoring the effectiveness of ERT. Our data show that the urinary proteome of Fabry naïve patients is different from that of normal subjects. In addition, biological pathways mainly affected by FD are related to immune response, inflammation, and energetic metabolism. In particular, the up-regulation of uromodulin, prostaglandin H2 d-isomerase and prosaposin in the urine of FD patients was demonstrated; these proteins might be involved in kidney damage at the tubular level, inflammation and immune response. Furthermore, comparing the expression of these proteins in Fabry patients before and after ERT treatment, a decrease of their concentration was observed, thus demonstrating the correlation between the identified markers and the effectiveness of the pharmacological treatment.

Geometry-independent assessment of renal volume in polycystic kidney disease from magnetic resonance imaging

Total renal volume (TRV) is an important quantitative indicator of the progression of autosomal dominant polycystic kidney disease (ADPKD). The Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease proposes a method for TRV computation based on manual tracing and geometric modeling. We developed a fast and nearly-automated technique for kidney segmentation and automatically compute TRV. In this study we aim to compare TRV estimates derived from these two different approaches. The highly-automated technique for the analysis of MR images was tested on 30 ADPKD patients. TRV was computed from both axial and coronal acquisitions, and compared to measurements based on geometric modeling by linear regression and Bland Altman analysis. In addition, to assess reproducibility, intra-observer and inter-observer variabilities were computed. The results of this study provide the feasibility of using a nearly-automated approach for accurate and fast evaluation of TRV also in markedly enlarged ADPKD kidneys.

[The nephropathy in the Anderson-Fabry disease: new recommendations for the diagnosis, the follow-up and the therapy]

Anderson-Fabry disease is a rare X-linked lysosomal storage disorder caused by mutations of the GLA gene that encodes alpha-galactosidase A. It is a characterized by the involvement of several systems: renal, neurological, hearth, cochleovestibular and cutaneous systems are the most involved. Despite recent studies have provided new insights in the this disease, there are still lacks and discrepancies among all insiders regarding the diagnosis, clinical and therapeutic management. Enzyme replacement have been demonstrated to improve the course of the disease, especially when the diagnosis is early. There are still some debates on diagnosis and management of patients, in particular in the heterozygote female and the start of enzyme replacement. Thus, an Italian board, composed by nephrologists, cardiologists, genetics, pediatricians and neurologists has been established in order to approve through a consensus a diagnostic and therapeutic Italian management. Authors report the renal clinical and therapeutic management, a useful tool either for expert physicians or for those with a few experience in the diagnosis and management of this disease.

Renal outcomes of agalsidase beta treatment for Fabry disease: role of proteinuria and timing of treatment initiation

BACKGROUND

The purpose of this study was to identify determinants of renal disease progression in adults with Fabry disease during treatment with agalsidase beta.

METHODS

Renal function was evaluated in 151 men and 62 women from the Fabry Registry who received agalsidase beta at an average dose of 1 mg/kg/2 weeks for at least 2 years. Patients were categorized into quartiles based on slopes of estimated glomerular filtration rate (eGFR) during treatment. Multivariate logistic regression analyses were used to identify factors associated with renal disease progression.

RESULTS

Men within the first quartile had a mean eGFR slope of -0.1 mL/min/1.73m(2)/year, whereas men with the most rapid renal disease progression (Quartile 4) had a mean eGFR slope of -6.7 mL/min/1.73m(2)/year. The risk factor most strongly associated with renal disease progression was averaged urinary protein:creatinine ratio (UP/Cr) ≥1 g/g (odds ratio 112, 95% confidence interval (95% CI) 4-3109, P = 0.0054). Longer time from symptom onset to treatment was also associated with renal disease progression (odds ratio 19, 95% CI 2-184, P = 0.0098). Women in Quartile 4 had the highest averaged UP/Cr (mean 1.8 g/g) and the most rapid renal disease progression: (mean slope -4.4 mL/min/1.73m(2)/year).

CONCLUSIONS

Adults with Fabry disease are at risk for progressive loss of eGFR despite enzyme replacement therapy, particularly if proteinuria is ≥1 g/g. Men with little urinary protein excretion and those who began receiving agalsidase beta sooner after the onset of symptoms had stable renal function. These findings suggest that early intervention may lead to optimal renal outcomes.

Genome-wide association study identifies susceptibility loci for IgA nephropathy

We carried out a genome-wide association study of IgA nephropathy, a major cause of kidney failure worldwide. We studied 1,194 cases and 902 controls of Chinese Han ancestry, with targeted follow up in Chinese and European cohorts comprising 1,950 cases and 1,920 controls. We identified three independent loci in the major histocompatibility complex, as well as a common deletion of CFHR1 and CFHR3 at chromosome 1q32 and a locus at chromosome 22q12 that each surpassed genome-wide significance (P values for association between 1.59 × 10⁻²⁶ and 4.84 × 10⁻⁹ and minor allele odds ratios of 0.63-0.80). These five loci explain 4-7% of the disease variance and up to a tenfold variation in interindividual risk. Many of the alleles that protect against IgA nephropathy impart increased risk for other autoimmune or infectious diseases, and IgA nephropathy risk allele frequencies closely parallel the variation in disease prevalence among Asian, European and African populations, suggesting complex selective pressures.

Assessment of kidney volume in polycystic kidney disease using magnetic resonance imaging without contrast medium

BACKGROUND/AIMS

Total renal volume (TRV) is an important index to evaluate the progression of autosomal-dominant polycystic kidney disease (ADPKD). TRV has been assessed by manually tracing renal contours from CT or MR scans, often employing contrast medium (CM). We developed a fast and nearly automated technique based on the analysis of MR images acquired without CM injection for TRV quantification.

METHODS

30 ADPKD patients underwent MRI. After the selection of one point inside each kidney for the entire volume, the automatic extraction of kidney contours was performed on each acquired slice; the segmentation procedure was based on region growing and on the application of morphological operators and curvature-based motion. The area inside each contour was calculated and TRV was derived. Volume measurements were validated by comparison with measurements obtained by stereology.

RESULTS

TRV estimated in patients was 768 ± 545 ml (range 161-3,111 ml). The automatic measurements were in excellent correlation with the manual ones (r = 0.99, y = x - 0.7), with a small bias and narrow limits of agreement in both absolute (-5 ± 37 ml) and percentage (-0.6 ± 9.6%) terms.

CONCLUSION

This preliminary study showed the feasibility of a fast and nearly automated method for determining TRV; importantly it does not require the use of potentially nephrotoxic CM.

Fabry disease: perspectives of urinary proteomics

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations in the gene encoding the lysosomal enzyme a-galactosidase A (a-GalA). The resulting deficiency in a-GalA activity leads to intra-lysosomal accumulation of neutral glycosphingolipids, mainly globotriaosylceramide (Gb3), in various organ systems. As a consequence, a multisystem disorder develops, culminating in strokes and progressive renal and cardiac dysfunction. Enzyme replacement therapy (ERT) offers a specific treatment for patients affected by FD, though monitoring treatment is hampered by a lack of surrogate markers of response. Furthermore, even if signs and symptoms of the disease become manifest in childhood, its diagnosis is often delayed. Biomarkers that predict disease progression and respond relatively quickly to effective therapy may be useful to follow individual patients or groups of patients. Here we report the use of 2 different mass spectrometry-based proteomic techniques to identify disease-associated compositional changes that can be used as early biomarkers of the pathology, as well as for monitoring the effectiveness of ERT. To this purpose, we compared the renal Fabry urinary proteome with normal (control) urine using, respectively, 2-dimensional gel electrophoresis and label-free quantification. Our preliminary results show that the urinary protein pattern of affected patients can be easily distinguished from that of healthy subjects both qualitatively and quantitatively, thus encouraging further studies in the search for FD-specific biomarkers using this proteomic approach.

Prognostic indicators of renal disease progression in adults with Fabry disease: natural history data from the Fabry Registry

BACKGROUND AND OBJECTIVES

These analyses were designed to characterize renal disease progression in untreated adults with Fabry disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from the Fabry Registry for 462 untreated adults (121 men and 341 women) who had at least two estimated GFR (eGFR) values over a span of ≥12 months before starting enzyme replacement therapy were included.

RESULTS

Most men (86 of 121, 71%) had more rapid loss of kidney function than the normal adult population (loss of eGFR > -1 ml/min per 1.73 m(2) per year), whereas fewer women (133 of 341, 39%) had rapid loss of kidney function. Patients with rapid progression had significantly higher mean averaged urinary protein to urinary creatinine ratios (UP/Cr) than patients with slower progression (1.5 versus 0.2 for men; 1.4 versus 0.5 for women; P < 0.0001). Patients were grouped into quartiles based on averaged UP/Cr; renal function in men declined more rapidly with higher UP/Cr, with the steepest declines observed in men with UP/Cr > 1.5 (mean eGFR slope, -5.6 ml/min per 1.73 m(2) per year; n = 30). eGFR slope declined more slowly in women, with the steepest declines observed in women with UP/Cr > 1.2 (mean eGFR slope, -1.3 ml/min per 1.73 m(2) per year; n = 85). Regression models of eGFR slope indicated that UP/Cr is the most important indicator of renal disease progression in adult Fabry patients. In women, lower baseline eGFR and age were also associated with renal disease progression. Women who had clinical events had more rapid loss of kidney function.

CONCLUSIONS

Urinary protein excretion is strongly associated with renal disease progression in men and women with Fabry disease.

Small fiber neuropathy in female patients with fabry disease

Recent studies suggest that heterozygous female Fabry disease (FD) patients develop peripheral neuropathy. We used skin biopsy to define somatic and autonomic peripheral nerve characteristics in 21 females with FD who were mainly asymptomatic and had normal renal function. Somatic epidermal and dermal autonomic nerve fiber reductions were found, prevalently in the leg, and no differences were found between symptomatic and asymptomatic individuals. Our findings suggest that females with FD, although asymptomatic, may have somatic and autonomic small fiber neuropathy.

Isolated microalbuminuria as the first clinical presentation of Fabry disease in an adult heterozygous female

Fabry disease (FD) is a rare X-linked disorder characterized by low or absent activity of the lysosomal enzyme α-glycosidase-A that leads to progressive accumulation of glycosphingolipids in different organs and tissues. Clinical manifestations vary from classic to atypical forms characterized by one prevalent organ involvement, and a renal variant has been described in men but not in women. However, little is known about renal manifestation in females affected by FD. We herein report a case of a 22-year-old female with isolated and persistent microalbuminuria as the only sign of FD. In light of the importance of early recognition and treatment of FD organ damage, this case should call for future studies to determine how to assess organ damage, investigate the existence of a ‘renal variant’ in FD female patients and determine when best to start enzyme replacement therapy (ERT).

Persistent left superior vena cava: what the interventional nephrologist needs to know

Variations in the course of the blood vessels are often incidental findings during clinical examination. Persistent left superior vena cava (PLSVC) is an uncommon anomaly, estimated to be present in about 0.3-0.5% of healthy individuals and in about 3-10% of patients with congenital heart disease. It results from the failure of the left anterior cardinal vein to degenerate during embryological development. Serious complications such as shock, angina and cardiac arrest have been described during catheterization in adults with a PLSVC. Since it frequently goes undiagnosed because of lack of symptoms when not accompanied by other anomalies, variations of the superior vena cava should be considered, especially when central venous catheterization via the subclavian or internal jugular vein is difficult. The embryological development, diagnosis, and clinical implications of a PLSVC are therefore reviewed in this article.

[Renal involvement in Fabry's disease: diagnosis, follow-up and enzyme replacement therapy]

Renal involvement in Fabry's disease in males starts at an early age with microalbuminuria and proteinuria and progresses rapidly towards end-stage renal disease requiring dialysis or renal transplantation. Renal involvement, together with cardiac and cerebral damage, is responsible for the severe morbidity and mortality in patients with Fabry's disease. In heterozygous female patients renal involvement has also been documented, but the onset of renal damage occurs later and the progression to end-stage renal disease is slower. Considering the relevance of renal damage in the prognosis of Fabry's disease, it is mandatory to point out the diagnostic criteria of Fabry's nephropathy and the modalities of follow-up of patients with renal involvement. The aim of this study is also to provide recommendations regarding the diagnosis, follow-up and indication for enzyme replacement therapy in patients with Fabry's disease.

Central nervous system involvement in Anderson-Fabry disease: a clinical and MRI retrospective study

BACKGROUND

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder caused by deficiency of alpha-galactosidase A. Central nervous system (CNS) manifestations consist mainly of cerebrovascular events. Brain MRI results are often abnormal.

PURPOSE

The aim of the study was to describe CNS involvement in a group of Italian patients with AFD.

METHODS

Clinical and brain MRI data of 43 patients with AFD (25 men, 41.94+/-10.83 years old and 18 women, 52.48+/-17.50 years old) were analysed retrospectively. 17 male patients and 7 female patients were under treatment with enzyme replacement therapy (ERT).

RESULTS

All 43 patients had signs or symptoms of AFD. 16 men (64%) and 13 women (72%) demonstrated CNS involvement, although with varying severity. Overall, 6 men and 5 women had suffered from cerebrovascular accidents with an age at onset of 33.64+/-13.65 years and 53.68+/-11.71 years, respectively. Brain MR images were abnormal in 16/25 men and in 13/16 women. During CNS monitoring, some patients receiving ERT (5/17 men and 2/6 women) demonstrated neurological deterioration, especially those who had presented with cerebrovascular disease already before starting ERT.

CONCLUSIONS

The study demonstrated a high frequency of CNS involvement in homozygous and heterozygous AFD patients, often characterised by early age at onset and abnormal brain MRIs. At present, ERT is widely used; however, potential beneficent effects may be disguised by the progression of irreversible pathology in short-term follow-up. Therefore, primary and secondary prophylaxes of cerebrovascular disease are extremely important.