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.

Efficacy and safety of the investigational complement C5 inhibitor zilucoplan in patients hospitalized with COVID-19: an open-label randomized controlled trial.

BACKGROUND: The efficacy and safety of complement inhibition in COVID-19 patients is unclear. METHODS: A multicenter randomized controlled, open-label trial. Hospitalized COVID-19 patients with signs of systemic inflammation and hypoxemia (PaO2/FiO2 below 350 mmHg) were randomized (2:1 ratio) to receive standard of care with or without the C5 inhibitor zilucoplan daily for 14 days, under antibiotic prophylaxis. The primary outcome was improvement in oxygenation at day 6 and 15. RESULTS: 81 patients were randomly assigned to zilucoplan (n = 55) or the control group (n = 26). 78 patients were included in the safety and primary analysis. Most were men (87%) and the median age was 63 years. The mean improvement in PaO2/FiO2 from baseline to day 6 was 56.4 mmHg in the zilucoplan group and 20.6 mmHg in the control group (mean difference + 35.8; 95% confidence interval (CI) - 9.4 to 80.9; p = 0.12), an effect also observed at day 15. Day 28 mortality was 9% in the zilucoplan and 21% in the control group (odds ratio 0.4; 95% CI 0.1 to 1.5). At long-term follow up, the distance walked in a 6-min test was 539.7 m in zilucoplan and 490.6 m in the control group (p = 0.18). Zilucoplan lowered serum C5b-9 (p < 0.001) and interleukin-8 (p = 0.03) concentration compared with control. No relevant safety differences between the zilucoplan and control group were identified. CONCLUSION: Administration of zilucoplan to COVID-19 patients in this proof-of-concept randomized trial was well tolerated under antibiotic prophylaxis. While not reaching statistical significance, indicators of respiratory function (PaO2/FiO2) and clinical outcome (mortality and 6-min walk test) suggest that C5 inhibition might be beneficial, although this requires further research in larger randomized studies.

Chronic kidney disease and an uncertain diagnosis of Fabry disease: approach to a correct diagnosis.

BACKGROUND AND OBJECTIVES: Screening for Fabry disease (FD), an X-linked lysosomal storage disorder, reveals a significant number of individuals with a genetic variant of unknown significance without classical FD manifestations; these variants in the α-galactosidase A gene often result in a high residual leukocyte α-galactosidase A and it is unclear whether these individuals suffer from FD. Therefore, a structured diagnostic approach is warranted. We present a diagnostic algorithm on how to approach adults with chronic kidney disease and an uncertain diagnosis of FD nephropathy. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: A modified Delphi procedure was conducted to reach consensus among 11 FD experts. A systematic review was performed to identify possible criteria that could confirm or exclude FD nephropathy. RESULTS: The gold standard for FD nephropathy was defined as characteristic storage on electron microscopy (EM) in a kidney biopsy in the absence of medication that may induce similar storage. The suggested criteria to confirm FD nephropathy are as follows: 'renal cysts', 'Maltese cross sign', 'immunohistochemical staining of Gb3 in urine' and 'high urinary Gb3'; and to exclude FD nephropathy: 'absence of renal cysts', 'small kidneys' and 'high protein excretion' were rejected because of low or uncertain specificity. Urinary Gb3 may be increased in other kidney diseases and there was no agreement on this criterion, although a third of the panel indicated that it is sufficient to diagnose FD nephropathy. The 'Maltese cross sign' and 'high urinary Gb3' were selected as red flags to suggest the possibility of FD nephropathy, but are not sufficient for a definite diagnosis of FD nephropathy. CONCLUSIONS: In adults with chronic kidney disease, an α-galactosidase A gene variant and an uncertain diagnosis of FD, a kidney biopsy with EM analysis should be performed to confirm or reject the diagnosis of FD nephropathy. Other criteria currently cannot substitute for a biopsy in these cases.

Fabry nephropathy: indications for screening and guidance for diagnosis and treatment by the European Renal Best Practice.

Fabry disease (FD) is an X-linked disorder of glycosphingolipid catabolism resulting in the accumulation of glycolipids including globotriaosylceramide in cells of various tissues resulting in end-organ manifestations. Initially, FD is typically characterized by angiokeratoma and recurrent episodes of neuropathic pain in the extremities occurring during childhood or adolescence. Most affected patients also exhibit a decreased ability to sweat. Later in life, FD results in left ventricular hypertrophy, proteinuria, renal failure and stroke. These later disease manifestations are non-specific and also common in diabetes, hypertension and atheromatosis and thus for most practitioners do not point into the direction of FD. As a consequence, FD is under-diagnosed and screening of high-risk groups is important for case finding, as is a thorough pedigree analysis of affected patients. In the nephrology clinic, we suggest to screen patients for FD when there is unexplained chronic kidney disease in males younger than 50 years and females of any age. In men, this can be performed by measuring α-galactosidase A activity in plasma, white blood cells or dried blood spots. In women, mutation analysis is necessary, as enzyme measurement alone could miss over one-third of female Fabry patients. A multidisciplinary team should closely monitor all known Fabry patients, with the nephrologist screening kidney impairment (glomerular filtration rate and proteinuria) on a regular basis. Transplanted Fabry patients have a higher mortality than the regular transplant population, but have acceptable outcomes, compared with Fabry patients remaining on dialysis. It is unclear whether enzyme replacement therapy (ERT) prevents deterioration of kidney function. In view of the lack of compelling evidence for ERT, and the low likelihood that a sufficiently powered randomized controlled trial on this topic will be performed, data of all patients with FD should be collected in a central registry.

Loss of phospholipase PLAAT3 causes a mixed lipodystrophic and neurological syndrome due to impaired PPARγ signaling.

Phospholipase A/acyltransferase 3 (PLAAT3) is a phospholipid-modifying enzyme predominantly expressed in neural and white adipose tissue (WAT). It is a potential drug target for metabolic syndrome, as Plaat3 deficiency in mice protects against diet-induced obesity. We identified seven patients from four unrelated consanguineous families, with homozygous loss-of-function variants in PLAAT3, who presented with a lipodystrophy syndrome with loss of fat varying from partial to generalized and associated with metabolic complications, as well as variable neurological features including demyelinating neuropathy and intellectual disability. Multi-omics analysis of mouse Plaat3-/- and patient-derived WAT showed enrichment of arachidonic acid-containing membrane phospholipids and a strong decrease in the signaling of peroxisome proliferator-activated receptor gamma (PPARγ), the master regulator of adipocyte differentiation. Accordingly, CRISPR-Cas9-mediated PLAAT3 inactivation in human adipose stem cells induced insulin resistance, altered adipocyte differentiation with decreased lipid droplet formation and reduced the expression of adipogenic and mature adipocyte markers, including PPARγ. These findings establish PLAAT3 deficiency as a hereditary lipodystrophy syndrome with neurological manifestations, caused by a PPARγ-dependent defect in WAT differentiation and function.

Shortcutting the diagnostic odyssey: the multidisciplinary Program for Undiagnosed Rare Diseases in adults (UD-PrOZA).

BACKGROUND: In order to facilitate the diagnostic process for adult patients suffering from a rare disease, the Undiagnosed Disease Program (UD-PrOZA) was founded in 2015 at the Ghent University Hospital in Belgium. In this study we report the five-year results of our multidisciplinary approach in rare disease diagnostics. METHODS: Patients referred by a healthcare provider, in which an underlying rare disease is likely, qualify for a UD-PrOZA evaluation. UD-PrOZA uses a multidisciplinary clinical approach combined with state-of-the-art genomic technologies in close collaboration with research facilities to diagnose patients. RESULTS: Between 2015 and 2020, 692 patients (94% adults) were referred of which 329 (48%) were accepted for evaluation. In 18% (60 of 329) of the cases a definite diagnosis was made. 88% (53 of 60) of the established diagnoses had a genetic origin. 65% (39 of 60) of the genetic diagnoses were made through whole exome sequencing (WES). The mean time interval between symptom-onset and diagnosis was 19 years. Key observations included novel genotype-phenotype correlations, new variants in known disease genes and the identification of three new disease genes. In 13% (7 of 53), identifying the molecular cause was associated with therapeutic recommendations and in 88% (53 of 60), gene specific genetic counseling was made possible. Actionable secondary findings were reported in 7% (12 of 177) of the patients in which WES was performed. CONCLUSION: UD-PrOZA offers an innovative interdisciplinary platform to diagnose rare diseases in adults with previously unexplained medical problems and to facilitate translational research.

Chronic intestinal pseudo-obstruction due to ß2microglobulin-amyloidosis in a patient on high-flux haemodialysis.

Dialysis-related amyloidosis (DRA) or ß2microglobulin (ß2m)-amyloidosis is a disorder caused by the inability to clear a protein called ß2m in patients with chronic kidney disease. It results in deposition of ß2m as amyloid fibrils, most commonly in bones and joints. Infrequently, visceral organs may be involved. With modern high-flux haemodialysis, DRA has become a rare disease, yet it may occur. We present a case of DRA in an 86-year-old woman. This case is particularly notable for its rare presentation as chronic intestinal pseudo-obstruction. It is of paramount importance to recognise this entity in order to reduce delay in treatment and avoid patients being frustrated not getting a diagnosis.

Two-tier approach for the detection of alpha-galactosidase A deficiency in kidney transplant recipients.

BACKGROUND: Anderson-Fabry disease (AFD) is an X-linked condition originating from a deficiency in alpha-galactosidase, a lysosomal enzyme. Multi-organ involvement ensues in early adulthood and vital organs are affected: the kidneys, brain, heart. Several reports however suggest that AFD is underdiagnosed. METHODS: We screened a kidney transplant population using a two-tier approach. The first tier was the determination of alpha-galactosidase A (AGALA) activity using a dried blood spot on filter paper (DBFP); in the second tier, patients with the lowest alpha-galactosidase levels were further subjected to mutation analysis of the GLA gene. RESULTS: From the database of 2328 patients, 1233 subjects met the inclusion criteria. Finally, after informed consent, 673 patients were screened (54.5%-395 women and 278 men). DBFP analysis resulted in a mean AGALA of 2.63 +/- 2.48 micromol/L/h (2.5 and 97.5 percentile were 0.0001 and 5.07 micromol/L/h, respectively). Eleven patients were subjected to further genetic analysis. In a male patient a pathogenic missense mutation p.Ala143Thr (c.427A>G) was identified. CONCLUSIONS: Our results show that the proposed approach can detect AFD patients in a until now seldomly screened high-risk group: kidney transplant patients. We conclude that screening for AFD in high-risk populations is a cost-effective, technically feasible and clinically valuable objective.

Future perspectives of genome-scale sequencing.

INTRODUCTION: In recent decades, we witnessed a revolution in genetic technology. Some 20 years ago, analysing a single gene was quite laborious and time-consuming. In addition, diagnostic testing was only available for selected genes. Nowadays, whole exome analysis - a technique enabling sequencing of all protein coding sequences in the entire genome - is gradually introduced in a clinical setting. Whole genome sequencing forms the ultimate exponent of this evolution and offers an even broader application. METHODS: A review of the application of these technologies in a diagnostic setting is presented. RESULTS: Whole exome sequencing has a prominent place in modern clinical diagnostics. It offers a cost- and time-efficient way to interrogate all protein coding portions of the genome leading to a quick and adequate diagnosis, also in cases of phenotypic heterogeneity. As sequencing costs continue to drop, whole genome sequencing will take over in the near future guaranteeing a further improvement of the quality of genetic testing. CONCLUSION: Due to technological advances in the past decades, the field of clinical diagnostics has changed dramatically. With techniques such as whole exome and whole genome sequencing, the diagnostic yield increases serving both the patient and the health care system.

Aggressive extensive cardiac mass in an HIV-1-infected patient: should we go for comfort therapy?

Cardiac masses are rare, the differential diagnosis includes infections with vegetations or abscesses, neoplasms, thrombi, and structural abnormalities. A pathology specimen is essential in therapeutic strategy planning for a cardiac mass, also if the primary imaging findings look dramatic at the start. Even in an inoperable setting, a life-saving therapy might be available. We report a case of a 49-year-old man, known with HIV-1, who was several times admitted with pericarditis. Now he was hospitalized with progressive lower limb edema, atrial fibrillation and detection of a giant cardiac mass in left and right atrium with infiltration of surrounding tissues. Given the extent and invasiveness of the mass, he was inoperable. Biopsy specimen was obtained and staging was performed by PET-CT scan. The diagnosis of stage IV Burkitt lymphoma with predominant extranodal cardiac involvement was withheld wherefore promptly aggressive therapy was started according to the GMALL B-NHL86 protocol. The therapy was downgraded to R-CHOP due to tolerance problems. He achieved a complete remission and during follow-up no relapse was detected.

Phenytoin intoxication in critically ill patients.

Phenytoin intoxication can result in major and possibly life-threatening disorders. Furthermore, the hepatic clearance can become saturated, thus, shifting the elimination from first- to zero-order kinetics. This results in a slow elimination of the compound in case of intoxication. The treatment modalities for phenytoin overdose are limited. Taking into account the high level of protein binding, the molecule is not easily eliminated from the body by means of extracorporal epuration. Although reports exist on the use of MARS (molecular adsorbents recirculating system) dialysis, peritoneal dialysis, and standard dialysis for the elimination, in practice, hemoperfusion, is the most often applied technique. The authors report the case of a hypoalbuminemic patient with severe neurologic signs of phenytoin intoxication (total concentration moderately elevated, free fraction high). A combination of high-flux dialysis and hemoperfusion resulted in a considerable extraction of the drug, accelerating the natural clearance from the body and ameliorating clinical signs of intoxication. In selected patients (with a high free fraction of phenytoin), high-flux dialysis may be a valuable alternative or adjuvant to hemoperfusion.

Gouty arthritis of the spine in a renal transplant patient: a clinical case report: an unusual presentation of a common disorder.

Axial gout is a well-documented but uncommon manifestation of gout. Its mimicking nature and the impracticality of axial joint aspiration might considerably delay its diagnosis. We report a case in a normouricemic renal transplant recipient, whereby the primary symptom of severe neck pain suggested pyogenic spondylodiscitis as an initial tentative diagnosis. Clinical findings included a high C-reactive protein concentration and elevated body temperature. The patient did not respond to empiric antibiotic treatment and suffered consecutive attacks of severe wrist and ankle pain in conjunction with a persistent fever. Blood and joint cultures were negative, but analysis of aspirated ankle joint fluid revealed monosodium urate crystals. A dual-energy computed tomography scan confirmed the presence of monosodium urate crystals in the costovertebral joints. Colchicine treatment dramatically improved the patient's clinical condition. Axial gout should be considered in transplant recipients with severe neck or back pain, fever, and increased inflammatory parameters with a high likelihood of an infectious etiology, despite the presence of paradoxically normal or even decreased serum urate concentrations. Dual-energy computed tomography is a noninvasive technique of possible benefit in the detection of axial gout when joint fluid aspiration is not deemed safe.

Recommendations for initiation and cessation of enzyme replacement therapy in patients with Fabry disease: the European Fabry Working Group consensus document.

INTRODUCTION: Fabry disease (FD) is a lysosomal storage disorder resulting in progressive nervous system, kidney and heart disease. Enzyme replacement therapy (ERT) may halt or attenuate disease progression. Since administration is burdensome and expensive, appropriate use is mandatory. We aimed to define European consensus recommendations for the initiation and cessation of ERT in patients with FD. METHODS: A Delphi procedure was conducted with an online survey (n = 28) and a meeting (n = 15). Patient organization representatives were present at the meeting to give their views. Recommendations were accepted with ≥75% agreement and no disagreement. RESULTS: For classically affected males, consensus was achieved that ERT is recommended as soon as there are early clinical signs of kidney, heart or brain involvement, but may be considered in patients of ≥16 years in the absence of clinical signs or symptoms of organ involvement. Classically affected females and males with non-classical FD should be treated as soon as there are early clinical signs of kidney, heart or brain involvement, while treatment may be considered in females with non-classical FD with early clinical signs that are considered to be due to FD. Consensus was achieved that treatment should not be withheld from patients with severe renal insufficiency (GFR < 45 ml/min/1.73 m(2)) and from those on dialysis or with cognitive decline, but carefully considered on an individual basis. Stopping ERT may be considered in patients with end stage FD or other co-morbidities, leading to a life expectancy of <1 year. In those with cognitive decline of any cause, or lack of response for 1 year when the sole indication for ERT is neuropathic pain, stopping ERT may be considered. Also, in patients with end stage renal disease, without an option for renal transplantation, in combination with advanced heart failure (NYHA class IV), cessation of ERT should be considered. ERT in patients who are non-compliant or fail to attend regularly at visits should be stopped. CONCLUSION: The recommendations can be used as a benchmark for initiation and cessation of ERT, although final decisions should be made on an individual basis. Future collaborative efforts are needed for optimization of these recommendations.

Prevalence of Fabry disease in a predominantly hypertensive population with left ventricular hypertrophy.

BACKGROUND: Patients with Fabry disease (FD) develop progressive left ventricular hypertrophy (LVH). In screening studies in patients with LVH, the prevalence of FD ranges from 0 to 12%. This variability is attributable to different factors like diverging inclusion and exclusion criteria, the evaluation of selected populations and suboptimal screening methods. In this study, we aimed to determine the prevalence of FD in an unselected population of everyday clinical practice presenting LVH, defined as a maximal end-diastolic septal or posterior wall thickness ≥ 13 mm, without exclusion of patients with arterial hypertension or valvular pathology, and using optimal screening methods. METHODS: In adult males, a two-tier approach was used; α-Galactosidase A (aGAL A) activity was measured using a dried bloodspot test (DBS) and diagnosis was confirmed by mutation analysis of the GLA gene. In females, mutation analysis was the primary screening tool. RESULTS: 362 men and 178 women were screened. Six patients were diagnosed with a genetic sequence alteration of the GLA gene. One man had a novel mutation, GLA p.Ala5Glu (c.44C>A), presenting as classical FD. Another man and three women had the previously described GLA p.Ala143Thr (c.427G>A) mutation, which generally presents as an attenuated phenotype. One woman had a novel sequence alteration c.639+6A>C, which appeared to be a polymorphism. All true Fabry patients had arterial hypertension (AHT), and one had hypertrophic obstructive cardiomyopathy (HOCM). CONCLUSIONS: In a group of unselected patients with LVH, we found a prevalence of Fabry disease of 0.9%. AHT or type of hypertrophy should not be an exclusion criterion for screening for FD.

Two-tier approach for the detection of alpha-galactosidase A deficiency in a predominantly female haemodialysis population.

INTRODUCTION: Fabry's disease (AFD) is an X-linked lysosomal storage disease, resulting from a deficiency in alpha-galactosidase A (AGALA). Untreated, this leads to precocious failure of vital organ function and death. As enzyme replacement therapy is available, it is of vital importance that affected individuals can be traced. MATERIALS AND METHODS: We set up a screening in the Flemish haemodialysis population using a two-tier approach. The first tier was a determination of alpha-galactosidase A activity using a dried blood spot on filter paper, in the second tier, patients with the lowest alpha-galactosidase levels were further subjected to mutation analysis of the GLA gene. RESULTS: 1284 patients (1047 women, 237 men) were evaluated for inclusion, eliminating patients with definite renal diagnoses. Total 922 patients (71.8 %) were screened (742 women, 180 men). Fifty seven patients were subjected to further genetic analysis. Three GLA mutation carriers were identified: two apparently nonrelated female patients carry the missense mutation p.Ala143Thr (c.427G > A), a missense mutation p.Trp236Arg (c.706T > C) was identified in a man. While the male patient had been clinically diagnosed with AFD, the female patients had remained unrecognized. Additional family based screening resulted in the identification of nine mutation carriers (four males and five females). DISCUSSION: We demonstrated that the prevalence of GLA mutation carriers in our haemodialysis population is 0.3%. Our results show that the proposed approach accurately detects AFD patients. We conclude that screening for AFD in high risk populations is a cost-effective, technically feasible and clinically valuable objective.

Delayed graft function in renal transplantation.

PURPOSE OF REVIEW: Delayed graft function is an important determinant of patient and graft survival. A complex of pathologic mechanisms intervenes in the pathophysiology of this outcome. This paper reviews the main processes involved in delayed graft function as they relate to five chronologically related stages: donor tissue quality, brain death and related stress, preservation variables, immune factors, and recipient variables. RECENT FINDINGS: Dialyzed delayed graft function and nondialyzed slow graft function both have a negative impact on graft survival and on the incidence of acute rejection. Expanded-criteria donors, older donors, and non-heart-beating donors are more frequently used. The long-term results of the use of well-selected non-heart-beating donors are surprisingly good. The process of ischemia/reperfusion injury is already initiated in the brain-death donor and continues during preservation of the graft. Graft-infiltrating T cells, heat shock proteins, and heme oxygenase-1 are implicated in the process. Modifications in immunosuppressive therapy and pharmacologic modulations have an effect on delayed graft function. Delayed graft function plays a part in the incidence of acute rejection, impaired graft function, and survival of patients and grafts. SUMMARY: This review discusses the current literature on several recent findings of pathophysiologic mechanisms of, and possible therapeutic interventions in, delayed graft function.