Unveiling the untreated: development of a database algorithm to identify potential Fabry disease patients in Germany.

BACKGROUND: Fabry disease (FD), an X-linked lysosomal storage disorder, is caused by mutations in the gene encoding α-galactosidase A, resulting in lysosomal accumulation of globotriaosylceramide and other glycosphingolipids. Early detection of FD is challenging, accounting for delayed diagnosis and treatment initiation. This study aimed to develop an algorithm using a logistic regression model to facilitate early identification of patients based on ICD-10-GM coding using a German Sickness Fund Database. METHODS: The logistic regression model was fitted on a binary outcome variable based on either a treated FD cohort or a control cohort (without FD). Comorbidities specific to the involved organs were used as covariates to identify potential FD patients with ICD-10-GM E75.2 diagnosis but without any FD-specific medication. Specificity and sensitivity of the model were optimized to determine a likely threshold. The cut-point with the largest values for the Youden index and concordance probability method and the lowest value for closest to (0,1) was identified as 0.08 for each respective value. The sensitivity and specificity for this cut-point were 80.4% and 79.8%, respectively. Additionally, a sensitivity analysis of the potential FD patients with at least two codes of E75.2 diagnoses was performed. RESULTS: A total of 284 patients were identified in the potential FD cohort using the logistic regression model. Most potential FD patients were < 30 years old and female. The identification and incidence rates of FD in the potential FD cohort were markedly higher than those of the treated FD cohort. CONCLUSIONS: This model serves as a tool to identify potential FD patients using German insurance claims data.

Ocular Manifestations of Fabry Disease: Report from a Tertiary Eye Care Center in Türkiye.

Objectives: To report ocular manifestations in patients with Fabry disease (FD) from a tertiary eye care center in Türkiye. Materials and Methods: This prospective, cross-sectional study included 30 eyes of 15 patients with FD. The diagnosis of FD was made based on a combination of clinical findings, genetic analysis, and biochemical evaluation. All participants underwent a detailed ophthalmic examination with special focus on the typical ocular features of FD (cornea verticillata, conjunctival aneurysms, cataract, retinal vessel tortuosity). Results: The mean age was 45±17 years (range: 22-75 years), with a female/male ratio of 2:3. All patients had tortuous conjunctival vessels and 12 patients (80%) had conjunctival aneurysms. Cornea verticillata was present in 10 patients (66.6%), lens opacification in 4 patients (26.6%), and retinal vascular tortuosity in 8 patients (53.3%). All patients had at least two different ocular findings; most (3 heterozygotes/7 hemizygotes) had a combination of corneal verticillata and conjunctival vessel abnormality. The conjunctiva, cornea, and retina were affected together in 5 hemizygous patients (33.3%). One hemizygous patient had all FDrelated ocular manifestations in both eyes. Conclusion: To our knowledge, this study is the first to describe the ocular manifestations of FD in the Turkish population. Although cornea verticillata is considered a hallmark of FD, it was absent in approximately one-third of patients. Moreover, cataract, another well-known feature of FD, was present in only 26.6% of the patients. Conjunctival vascular abnormality alone seems to be quite rare in FD, although it often accompanies other ocular manifestations. Therefore, recognition of other mild findings and special consideration of their associations may increase the diagnostic value of ocular findings in FD.

Analysis of Globotriaosylceramide (Gb3) in Liquid Urine: A Straightforward Assay Using Tandem Mass Spectrometry.

Fabry disease (FD) is a lysosomal storage disorder caused by variants in the GLA gene encoding α-galactosidase A, an enzyme required for catabolism of globotriaosylceramide (Gb3). Accumulation of Gb3 in patients' cells, tissues, and biological fluids causes clinical manifestations including ventricular hypertrophy, renal insufficiency, and strokes. This protocol describes a methodology to analyze urinary Gb3 and creatinine. Samples are diluted with an internal standard solution containing Gb3(C17:0) and creatinine-D3, centrifuged, and directly analyzed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) using an 8.7-min method. Eight Gb3 isoforms [C16:0, C18:0, C20:0, C22:1, C22:0, C24:1, C24:0, and (C24:0)OH] are analyzed and the total is normalized to creatinine. Confirmation ions are monitored to detect potential interferences. The Gb3 limit of quantification is 0.023 µg/ml. Its interday coefficients of variation (3 concentrations measured) are ≤15.4%. This method minimizes matrix effects (≤6.5%) and prevents adsorption or precipitation of Gb3. Urine samples are stable (bias <15%) for 2 days at 21°C, 7 days at 4°C, and 4 freeze/thaw cycles, whereas prepared samples are stable for 5 days at 21°C, and 14 days at 4°C. The Gb3/creatinine age-related upper reference limits (mean + 2 standard deviations) are 29 mg/mol creatinine (<7 years) and 14 mg/mol creatinine (≥7 years). This simple, robust protocol has been fully validated (ISO 15189) and provides a valuable tool for diagnosis and monitoring of FD patients. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Analysis of urinary globotriaosylceramide (Gb3) and creatinine by UHPLC-MS/MS Support Protocol 1: Preparation of the urinary quality controls Support Protocol 2: Preparation of the urine matrix used for the Gb3 calibration curve Support Protocol 3: Preparation of the Gb3 calibrators Support Protocol 4: Preparation of the working solution containing the internal standards Support Protocol 5: Preparation of the creatinine calibrators Support Protocol 6: Preparation of the UHPLC solutions and mobile phases.

LysoGb3 quantification facilitates phenotypic categorization of Fabry disease patients: Insights gained by a novel MS/MS method.

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disease resulting from pathogenic variants in the GLA gene coding α-galactosidase A (AGAL) and cleaving terminal alpha-linked galactose. Globotriaosylceramide (Gb3) is the predominantly accumulated sphingolipid. Gb3, deacylated-Gb3 (lysoGb3), and methylated-Gb3 (metGb3) have been suggested as FD biomarkers. MATERIALS AND METHODS: We developed a novel LC-MS/MS method for assessing lysoGb3 levels in plasma and Gb3 and metGb3 in urine and tested 62 FD patients, 34 patients with GLA variants of unknown significance (VUS) and 59 healthy controls. AGAL activity in white blood cells (WBCs) and plasma was evaluated in parallel. RESULTS: In males, lysoGb3 concentrations in plasma separated classic and late-onset FD patients from each other and from individuals carrying GLA VUS and healthy controls. Calculating AGAL activity/plasmatic lysoGb3 ratio allowed to correctly categorize all females with classic and majority of patients with late-onset FD phenotypes. Correlation of AGAL activity in WBCS with lipid biomarkers identified threshold activity values under which the biomarkers' concentrations increase. CONCLUSION: We developed a novel simplified LC-MS/MS method for quantitation of plasma lysoGb3. AGAL activity/plasma lysoGb3 ratio was identified as the best predictor for FD. AGAL activity correlated with plasma lysoGb3 and corresponded to individual FD phenotypes.

8th Update on Fabry Disease: Biomarkers, Progression and Treatment Opportunities in 2024.

Fabry Update.

Identification of a novel nonsense mutation in α-galactosidase A that causes Fabry disease in a Chinese family.

Fabry disease, a lysosomal storage disease, is an uncommon X-linked recessive genetic disorder stemming from abnormalities in the alpha-galactosidase gene (GLA) that codes human alpha-Galactosidase A (α-Gal A). To date, over 800 GLA mutations have been found to cause Fabry disease (FD). Continued enhancement of the GLA mutation spectrum will contribute to a deeper recognition and underlying mechanisms of FD. In this study, a 27-year-old male proband exhibited a typical phenotype of Fabry disease. Subsequently, family screening for Fabry disease was conducted, and high-throughput sequencing was employed to identify the mutated gene. The three-level structure of the mutated protein was analyzed, and its subcellular localization and enzymatic activity were determined. Apoptosis was assessed in GLA mutant cell lines to confirm the functional effects. As a result, a new mutation, c.777_778del (p. Gly261Leufs*3), in the GLA gene was identified. The mutation caused a frameshift during translation and the premature appearance of a termination codon, which led to a partial deletion of the domain in C-terminal region and altered the protein's tertiary structure. In vitro experiments revealed a significant reduction of the enzymatic activity in mutant cells. The expression was noticeably decreased at the mRNA and protein levels in mutant cell lines. Additionally, the subcellular localization of α-Gal A changed from a homogeneous distribution to punctate aggregation in the cytoplasm. GLA mutant cells exhibited significantly higher levels of apoptosis compared to wild-type cells.

Detection of α-Galactosidase A Reaction in Samples Extracted from Dried Blood Spots Using Ion-Sensitive Field Effect Transistors.

Fabry disease is a lysosomal storage disorder caused by a significant decrease in the activity or absence of the enzyme α-galactosidase A. The diagnostics of Fabry disease during newborn screening are reasonable, due to the availability of enzyme replacement therapy. This paper presents an electrochemical method using complementary metal-oxide semiconductor (CMOS)-compatible ion-sensitive field effect transistors (ISFETs) with hafnium oxide-sensitive surfaces for the detection of α-galactosidase A activity in dried blood spot extracts. The capability of ISFETs to detect the reaction catalyzed by α-galactosidase A was demonstrated. The buffer composition was optimized to provide suitable conditions for both enzyme and ISFET performance. The use of ISFET structures as sensor elements allowed for the label-free detection of enzymatic reactions with melibiose, a natural substrate of α-galactosidase A, instead of a synthetic fluorogenic one. ISFET chips were packaged with printed circuit boards and microfluidic reaction chambers to enable long-term signal measurement using a custom device. The packaged sensors were demonstrated to discriminate between normal and inhibited GLA activity in dried blood spots extracts. The described method offers a promising solution for increasing the widespread distribution of newborn screening of Fabry disease.

Inflammatory and Cardiovascular Biomarkers to Monitor Fabry Disease Progression.

Fabry disease is an invalidating multisystemic disorder affecting α-Galactosidase, a rate-limiting hydrolase dedicated to lipid catabolism. Non-metabolized substrates, such as Globotriaosylceramide and its derivatives trigger the direct or indirect activation of inflammatory events and endothelial dysfunction. In spite of the efficacy demonstrated by enzyme replacement therapy or pharmacological chaperones in delaying disease progression, few studies have analyzed whether these treatments can improve the pro-inflammatory state of FD patients. Therefore, the aim of this work was to assess cytokines and cardiovascular risk-related proteins detectable in plasma from FD patients, whether treated or not with ERT, to evaluate the reliability of these markers in monitoring disease stage and treatment effects. We identified inflammatory and endothelial dysfunction markers (ADAMTS-13, TNF-α, GDF-15, MIP-1ß, VEGFA, MPO, and MIC-1) that cooperate in a common pathway and are increased in FD patients' plasma samples. As shown by the assessment of these proteins over time, they can help to evaluate the risk of higher severity in FD, as well as ERT effects. Even though the analyzed proteins cannot be considered as proper biomarkers due to their non-specificity to FD, taken together they can provide a signature of reference molecules with prognostic value for early diagnosis, and evaluation of disease progression and treatment efficacy, using blood samples.

Diagnosis of Fabry Disease Using Alpha-Galactosidase A Activity or LysoGb3 in Blood Fails to Identify Up to Two Thirds of Female Patients.

Anderson-Fabry disease is a lysosomal storage disorder caused by mutations in the GLA gene, which encodes the enzyme α-galactosidase A. The GLA gene is located on the X-chromosome, causing an X-linked pathology: due to lyonization, female patients usually manifest a variable symptomatology, ranging from asymptomatic to severe phenotypes. The confirmation of the clinical diagnosis of Fabry disease, achieved by measuring α-galactosidase A activity, which is usually the first test used, shows differences between male and female patients. This assay is reliable in male patients with causative mutations in the GLA gene, in whom the enzymatic activity is lower than normal values; on the other hand, in female Fabry patients, the enzymatic activity is extremely variable between normal and pathological values. These fluctuations are also found in female patients' blood levels of globotriaosylsphingosine (LysoGb3) for the same reason. In this paper, we present a retrospective study conducted in our laboratories on 827 Fabry patients with causative mutations in the GLA gene. Our results show that 100% of male patients had α-galactosidase A activity below the reference value, while more than 70% of female patients had normal values. It can also be observed that almost half of the female patients with pathogenic mutations in the GLA gene showed normal values of LysoGb3 in blood. Furthermore, in women, blood LysoGb3 values can vary over time, as we show in a clinical case presented in this paper. Both these tests could lead to missed diagnoses of Fabry disease in female patients, so the analysis of the GLA gene represents the main diagnostic test for Fabry disease in women to date.

Patient-reported experience with Fabry disease and its management in the real-world setting: results from a double-blind, cross-sectional survey of 280 respondents.

BACKGROUND: Fabry disease (FD) is a rare X-linked lysosomal storage disorder with a heterogeneous clinical presentation. Patients with FD may exhibit early signs/symptoms including neuropathic pain, gastrointestinal complaints, and dermatologic manifestations. FD may ultimately progress to renal, neurologic, and cardiac dysfunction. Current treatments for FD have significantly improved the management and outcomes for patients with FD, but important clinical and convenience limitations still exist. METHODS: To illuminate the impact of FD on daily life from the patient's perspective, we asked adult patients (≥ 18 years old) with FD in the United States and Canada to complete a 33-question online survey to assess patient-reported disease severity, management, and treatment outcomes. RESULTS: A total of 280 respondents with FD completed the survey; they had a mean age of 47 years, and 68% (191/280) were women. Most were currently receiving FD treatment (84%, 234/280) with enzyme replacement therapy (ERT) (89%, 208/234) or chaperone therapy (11%, 26/234). Common symptoms included low energy/fatigue (72%, 201/280), tingling (62%, 174/280) or pain in the hands/feet (60%, 168/280), ringing in ears/hearing loss (54%, 151/280), general body pains/pain crises (51%, 143/280), and abdominal/stomach pain (50%, 140/280). More than half (51%, 144/280) of respondents reported their symptoms as bothersome (38%, 106/280) or difficult to control (14%, 38/280). Temporary symptom worsening between infusions was reported by about half of respondents: 51% (108/211) currently receiving ERT and 48% (14/29) previously receiving ERT. Only 48% (59/122) of respondents reported their symptom worsening to their physician. Of those who reported it, 41% (24/59) said that their physician prescribed medication to manage their symptoms or changed their treatment regimen. CONCLUSIONS: Our analysis highlights the gap between current standard-of-care in disease monitoring and patient perception of disease progression among patients with FD. This information may be helpful for healthcare providers and drug developers seeking to improve the care of patients with FD by addressing unmet needs of high relevance.

Elevated interleukin-8 expression by skin fibroblasts as a potential contributor to pain in women with Fabry disease.

Fabry disease (FD) is a lysosomal storage disorder of X-linked inheritance. Mutations in the α-galactosidase A gene lead to cellular globotriaosylceramide (Gb3) depositions and triggerable acral burning pain in both sexes as an early FD symptom of unknown pathophysiology. We aimed at elucidating the link between skin cells and nociceptor sensitization contributing to FD pain in a sex-associated manner. We used cultured keratinocytes and fibroblasts of 27 adult FD patients and 20 healthy controls. Epidermal keratinocytes and dermal fibroblasts were cultured and immunoreacted to evaluate Gb3 load. Gene expression analysis of pain-related ion channels and pro-inflammatory cytokines was performed in dermal fibroblasts. We further investigated electrophysiological properties of induced pluripotent stem cell (iPSC) derived sensory-like neurons of a man with FD and a healthy man and incubated the cells with interleukin 8 (IL-8) or fibroblast supernatant as an in vitro model system. Keratinocytes displayed no intracellular, but membrane-bound Gb3 deposits. In contrast, fibroblasts showed intracellular Gb3 and revealed higher gene expression of potassium intermediate/small conductance calcium-activated potassium channel 3.1 (KCa 3.1, KCNN4) in both, men and women with FD compared to controls. Additionally, cytokine expression analysis showed increased IL-8 RNA levels only in female FD fibroblasts. Patch-clamp studies revealed reduced rheobase currents for both iPSC neuron cell lines incubated with IL-8 or fibroblast supernatant of women with FD. We conclude that Gb3 deposition in female FD patient skin fibroblasts may lead to increased KCa3.1 activity and IL-8 secretion. This may result in cutaneous nociceptor sensitization as a potential mechanism contributing to a sex-associated FD pain phenotype.

Flow Cytometry-Based Assay to Detect Alpha Galactosidase Enzymatic Activity at the Cellular Level.

BACKGROUND: Fabry disease is a progressive, X chromosome-linked lysosomal storage disorder with multiple organ dysfunction. Due to the absence or reduced activity of alpha-galactosidase A (AGAL), glycosphingolipids, primarily globotriaosyl-ceramide (Gb3), concentrate in cells. In heterozygous women, symptomatology is heterogenous and currently routinely used fluorometry-based assays measuring mean activity mostly fail to uncover AGAL dysfunction. The aim was the development of a flow cytometry assay to measure AGAL activity in individual cells. METHODS: Conventional and multispectral imaging flow cytometry was used to detect AGAL activity. Specificity was validated using the GLA knockout (KO) Jurkat cell line and AGAL inhibitor 1-deoxygalactonojirimycin. The GLA KO cell line was generated via CRISPR-Cas9-based transfection, validated with exome sequencing, gene expression and substrate accumulation. RESULTS: Flow cytometric detection of specific AGAL activity is feasible with fluorescently labelled Gb3. In the case of Jurkat cells, a substrate concentration of 2.83 nmol/mL and 6 h of incubation are required. Quenching of the aspecific exofacial binding of Gb3 with 20% trypan blue solution is necessary for the specific detection of lysosomal substrate accumulation. CONCLUSION: A flow cytometry-based assay was developed for the quantitative detection of AGAL activity at the single-cell level, which may contribute to the diagnosis of Fabry patients.

Vericiguat improves cardiac function and microcirculation of a male patient with Fabry disease: A case report.

Fabry disease (FD) is a rare X chromosome-linked disorder and can be easily misdiagnosed. Here, we report the case of a 69-year-old male patient with FD who developed heart failure and showed extremely high pulmonary artery pressure. His initial symptom was recurrent atrial fibrillation. The left and right atrial inner diameters were large, and the ventricular wall was thick. Gene analysis which showed GLA c.215T>C p.Met72Thr mutation and single photon emission computed tomography indicated the diagnosis of FD with coronary microvascular dysfunction. The patient was prescribed anti-heart failure drugs, including vericiguat. Following the treatment, his heart function and microvascular perfusion significantly improved, which might be due to the beneficial effects of vericiguat.

What should rheumatologists know about Gaucher disease and Fabry disease? Connecting the dots for an overview.

Gaucher and Fabry diseases are lysosomal storage disorders in which deficient enzyme activity leads to pathological accumulation of sphingolipids. These diseases have a broad phenotypic presentation. Musculoskeletal symptoms and pain complaints are frequently reported by patients. Thus, rheumatologists can be contacted by these patients, contributing to the correct diagnosis, earlier indication of appropriate treatment and improvement of their prognosis. This review describes important concepts about Gaucher and Fabry diseases that rheumatologists should understand to improve patients' quality of life and change the natural history of these diseases.

[Genotype-phenotype analysis of Fabry disease caused by GLA gene variation in a pedigree].

Objective: To investigate the clinical phenotype and genetic characteristics of patients with Fabry disease caused by a GLA variant, IVS4+919G>A. Methods: It was a prospective study. Fabry disease screening was conducted among high-risk population in Ninghai from October 2021 to August 2023. Those children with decreased α-galactosidase enzyme activity<2.40 µmol/(L·h) or elavated Lyso-GL-3 level>1.10 µg/L in dried blood spot (DBS) method underwent GLA genetic testing for diagnosis confirmation. Meanwhile, family screening was carried out. A proband and his family members diagnosed with Fabry disease were research subjects. The clinical and genetic characteristics of patients with Fabry disease caused by the GLA variant (IVS4+919G>A) were analyzed. Results: The female proband aged 9.8 years with pain in both lower limbs as the initial symptom was found to have a heterozygous GLA variant IVS4+919G>A among 102 patients. In family screening, there were 4 family members (proband's father, elder sister, elder male cousin and elder female cousin) with Fabry disease and a family member (proband's fifth aunt) with a GLA variant. Among these 4 diagnosed family members, the elder male cousin of the proband, a boy aged 13.2 years had a heterozygous GLA variant, IVS4+919G>A with intermittent pain in both lower limbs as the initial symptom. The proband's father had knee joint pain. The proband's elder sister had decreased vision and his elder female cousin had no obvious symptoms. The proband's fifth aunt with a GLA variant had decreased vision. Conclusions: High-risk screening in children and family screening are helpful for early diagnosis and treatment of Fabry disease. Neuropathic pain may be a early symptom in children with Fabry disease caused by the GLA variant, IVS4+919G>A.

Anderson-Fabry disease management: role of the cardiologist.

Anderson-Fabry disease (AFD) is a lysosomal storage disorder characterized by glycolipid accumulation in cardiac cells, associated with a peculiar form of hypertrophic cardiomyopathy (HCM). Up to 1% of patients with a diagnosis of HCM indeed have AFD. With the availability of targeted therapies for sarcomeric HCM and its genocopies, a timely differential diagnosis is essential. Specifically, the therapeutic landscape for AFD is rapidly evolving and offers increasingly effective, disease-modifying treatment options. However, diagnosing AFD may be difficult, particularly in the non-classic phenotype with prominent or isolated cardiac involvement and no systemic red flags. For many AFD patients, the clinical journey from initial clinical manifestations to diagnosis and appropriate treatment remains challenging, due to late recognition or utter neglect. Consequently, late initiation of treatment results in an exacerbation of cardiac involvement, representing the main cause of morbidity and mortality, irrespective of gender. Optimal management of AFD patients requires a dedicated multidisciplinary team, in which the cardiologist plays a decisive role, ranging from the differential diagnosis to the prevention of complications and the evaluation of timing for disease-specific therapies. The present review aims to redefine the role of cardiologists across the main decision nodes in contemporary AFD clinical care and drug discovery.

Newborn genetic screening for Fabry disease: Insights from a retrospective analysis in Nanjing, China.

Fabry disease (FD), an X-linked disorder resulting from dysfunction of α-galactosidase A, can result in significant complications. Early intervention yields better outcomes, but misdiagnosis or delayed diagnosis is common, impacting prognosis. Thus, early detection is crucial in the clinical diagnosis and treatment of FD. While newborn screening for FD has been implemented in certain regions, challenges persist in enzyme activity detection techniques, particularly for female and late-onset patients. Further exploration of improved screening strategies is warranted. This study retrospectively analyzed genetic screening results for pathogenic GLA variants in 17,171 newborns. The results indicated an estimated incidence of FD in the Nanjing region of China of approximately 1 in 1321. The most prevalent pathogenic variant among potential FD patients was c.640-801G > A (46.15 %). Furthermore, the residual enzyme activity of the pathogenic variant c.911G > C was marginally higher than that of other variants, and suggesting that genetic screening may be more effective in identifying potential female and late-onset patients compared to enzyme activity testing. This research offers initial insights into the effectiveness of GLA genetic screening and serves as a reference for early diagnosis, treatment, and genetic counseling in FD.

Experience with cascade screening: A comprehensive family pedigree analysis of two index patients with Fabry disease.

The wide range of clinical symptoms observed in patients with Fabry disease (FD) often leads to delays in diagnosis and initiation of treatment. Delayed initiation of therapy may result in end-organ damage, such as chronic renal failure, hypertrophic cardiomyopathy, and stroke. Although some tools are available to identify undiagnosed patients, new comprehensive screening methods are needed. In this study, the outcomes of the cascade screening applied to three index cases with FD from 2 familes were investigated. In the pedigree analysis, 280 individuals were included; out of them, 131 individuals underwent genetic testing and cascade screening for FD. During the screening program, a total of 45 individuals were diagnosed, with a diagnostic ratio of 1:15. The average age at diagnosis for all individuals was 30.9 ± 17.7 years, and %25 were pediatric cases (mean age 9.5 ± 5.9 years). Thirty affected relatives were diagnosed from the two index cases in Family 1 and 15 individuals were diagnosed from one index case in Family 2. There were 13 consanguineous marriages observed among 2 pedigres, in two both spouses  were affected, leading to two homozygous affected daughters in one couple. In regions where there is a high prevalence of consanguineous marriages, implementing the cascade screening approach to identify all individuals at risk can be beneficial for patients with FD, specifically women and children.

What Is Hidden in Patients with Unknown Nephropathy? Genetic Screening Could Be the Missing Link in Kidney Transplantation Diagnosis and Management.

Between 15-20% of patients with end stage renal disease (ESRD) do not know the cause of the primary kidney disease and can develop complications after kidney transplantation. We performed a genetic screening in 300 patients with kidney transplantation, or undiagnosed primary renal disease, in order to identify the primary disease cause and discriminate between overlapping phenotypes. We used a custom-made panel for next-generation sequencing (Agilent technology, Santa Clara, CA, USA), including genes associated with Fabry disease, podocytopaties, complement-mediated nephropathies and Alport syndrome-related diseases. We detected candidate diagnostic variants in genes associated with nephrotic syndrome and Focal Segmental Glomerulosclerosis (FSGS) in 29 out of 300 patients, solving about 10% of the probands. We also identified the same genetic cause of the disease (PAX2: c.1266dupC) in three family members with different clinical diagnoses. Interestingly we also found one female patient carrying a novel missense variant, c.1259C>A (p.Thr420Lys), in the GLA gene not previously associated with Fabry disease, which is in silico defined as a likely pathogenic and destabilizing, and associated with a mild alteration in GLA enzymatic activity. The identification of the specific genetic background may provide an opportunity to evaluate the risk of recurrence of the primary disease, especially among patient candidates living with a donor kidney transplant.