Juan Politei

Stroke in Fabry disease frequently occurs before diagnosis and in the absence of other clinical events: natural history data from the Fabry Registry.

Background and Purpose— Stroke is a common and serious clinical manifestation of Fabry disease, an X-linked lysosomal storage disorder caused by deficiency of &agr;-galactosidase A activity. This study was undertaken to better understand the natural history of cerebrovascular manifestations of Fabry disease. Methods— Data from 2446 patients in the Fabry Registry were analyzed to identify clinical characteristics of patients experiencing stroke during the natural history period (ie, before enzyme replacement therapy). Results— A total of 138 patients (86 of 1243 males [6.9%] and 52 of 1203 females [4.3%]) experienced strokes. Median age at first stroke was 39.0 years in males and 45.7 years in females. Most patients (70.9% of males and 76.9% of females) had not experienced renal or cardiac events before their first stroke. Fifty percent of males and 38.3% of females experienced their first stroke before being diagnosed with Fabry disease. Thirty patients (21 males and 9 females) had strokes at age <30 years. Most patients (86.8%) had ischemic strokes, but 16.9% of males and 6.9% of females had hemorrhagic strokes, among those for whom stroke type was reported. At the most recently available follow-up examination after their first stroke, 60% of males and 25.5% of females exhibited stage 3 to 5 chronic kidney disease and 66.1% of males and 59.5% of females had left ventricular hypertrophy. Conclusions— All patients with Fabry disease, regardless of age or gender, should be monitored for possible cerebrovascular complications, as stroke can occur in the absence of other key signs of the disease.

Fibrosis: A key feature of Fabry disease with potential therapeutic implications

Fabry disease is a rare X-linked hereditary disease caused by mutations in the AGAL gene encoding the lysosomal enzyme alpha-galactosidase A. Enzyme replacement therapy (ERT) is the current cornerstone of Fabry disease management. Involvement of kidney, heart and the central nervous system shortens life span, and fibrosis of these organs is a hallmark of the disease. Fibrosis was initially thought to result from tissue ischemia secondary to endothelial accumulation of glycosphingolipids in the microvasculature. However, despite ready clearance of endothelial deposits, ERT is less effective in patients who have already developed fibrosis. Several potential explanations of this clinical observation may impact on the future management of Fabry disease. Alternative molecular pathways linking glycosphingolipids and fibrosis may be operative; tissue injury may recruit secondary molecular mediators of fibrosis that are unresponsive to ERT, or fibrosis may represent irreversible tissue injury that limits the therapeutic response to ERT. We provide an overview of Fabry disease, with a focus on the assessment of fibrosis, the clinical consequences of fibrosis, and recent advances in understanding the cellular and molecular mechanisms of fibrosis that may suggest novel therapeutic approaches to Fabry disease.

Early diagnosis of peripheral nervous system involvement in Fabry disease and treatment of neuropathic pain: the report of an expert panel

BackgroundFabry disease is an inherited metabolic disorder characterized by progressive lysosomal accumulation of lipids in a variety of cell types, including neural cells. Small, unmyelinated nerve fibers are particularly affected and small fiber peripheral neuropathy often clinically manifests at young age. Peripheral pain can be chronic and/or occur as provoked attacks of excruciating pain. Manifestations of dysfunction of small autonomic fibers may include, among others, impaired sweating, gastrointestinal dysmotility, and abnormal pain perception. Patients with Fabry disease often remain undiagnosed until severe complications involving the kidney, heart, peripheral nerves and/or brain have arisen.MethodsAn international expert panel convened with the goal to provide guidance to clinicians who may encounter unrecognized patients with Fabry disease on how to diagnose these patients early using simple diagnostic tests. A further aim was to offer recommendations to control neuropathic pain.ResultsWe describe the neuropathy in Fabry disease, focusing on peripheral small fiber dysfunction - the hallmark of early neurologic involvement in this disorder. The clinical course of peripheral pain is summarized, and the importance of medical history-taking, including family history, is highlighted. A thorough physical examination (e.g., angiokeratoma, corneal opacities) and simple non-invasive sensory perception tests could provide clues to the diagnosis of Fabry disease. Reported early clinical benefits of enzyme replacement therapy include reduction of neuropathic pain, and adequate management of residual pain to a tolerable and functional level can substantially improve the quality of life for patients.ConclusionsOur recommendations can assist in diagnosing Fabry small fiber neuropathy early, and offer clinicians guidance in controlling peripheral pain. This is particularly important since management of pain in young patients with Fabry disease appears to be inadequate.

Cerebrovascular Involvement in Fabry Disease: Current Status of Knowledge

Fabry disease (FD) is a rare and highly debilitating lysosomal storage disorder that results from a total lack of, or deficiency in, the enzyme α-galactosidase A (α-Gal A) because of mutations in the GLA gene.1 FD is inherited as an X-linked trait; many of the male patients develop a classic severe phenotype with early onset of symptoms, whereas heterozygous females exhibit phenotypes ranging from asymptomatic to major involvement of vital organs.2 Most families inherit private mutations; to date, >600 mutations have been identified and are listed in the online FD database (Fabry-database.org).3 The deficiency in α-Gal A causes the accumulation of globotriaosylceramide (GL-3; also abbreviated Gb3) in various cellular compartments, particularly lysosomes, causing structural damage and cellular dysfunction, as well as triggering secondary, tissue-level responses, such as inflammation, ischemia, hypertrophy, and the development of fibrosis resulting in progressive organ dysfunction.4 Deacylated globotriaosylceramide (lyso- globotriaosylceramide [lyso-GL-3]) has also been shown to be present in increased concentrations in the plasma of patients with FD. It has been suggested that lyso-GL-3 promotes GL-3 accumulation, induces proliferation of smooth muscle cells in vitro, and may have deleterious effects on the intima and media of small arterioles.5 Many cell types are involved in FD pathology, including vascular cells (endothelial and smooth muscle cells), cardiac cells (cardiomyocytes and valvular cells), a variety of renal cells (tubular and glomerular cells, and podocytes), and nerve cells.2 The underlying pathophysiological mechanisms of FD are complex and incompletely understood.6 Early pathophysiological changes are thought to predominantly involve the microvasculature.7 As age increases, arterial remodeling and intima-media thickening in medium-to-large caliber vessels occur.2 The first clinical symptoms of FD occur in childhood (eg, neuropathic pain, hypohidrosis, and gastrointestinal problems)8 and are primarily because of autonomic neuropathy.9 As the disease …

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.

Time to treatment benefit for adult patients with Fabry disease receiving agalsidase β: data from the Fabry Registry

Background Agalsidase β is a form of enzyme replacement therapy for Fabry disease, a genetic disorder characterised by low α-galactosidase A activity, accumulation of glycosphingolipids and life-threatening cardiovascular, renal and cerebrovascular events. In clinical trials, agalsidase β cleared glycolipid deposits from endothelial cells within 6 months; clearance from other cell types required sustained treatment. We hypothesised that there might be a ‘lag time’ to clinical benefit after initiating agalsidase β treatment, and analysed the incidence of severe clinical events over time in patients receiving agalsidase β. Methods The incidence of severe clinical events (renal failure, cardiac events, stroke, death) was studied in 1044 adult patients (641 men, 403 women) enrolled in the Fabry Registry who received agalsidase β (average dose 1 mg/kg every 2 weeks) for up to 5 years. Results The incidence of all severe clinical events was 111 per 1000 person-years (95% CI 84 to 145) during the first 6 months. After 6 months, the incidence decreased and remained stable within the range of 40–58 events per 1000 patient-years. The largest decrease in incidence rates was among male patients and those aged ≥40 years when agalsidase β was initiated. Conclusions Contrary to the expected increased incidence of severe clinical events with time, adult patients with Fabry disease had decreased incidence of severe clinical events after 6 months treatment with agalsidase β 1 mg/kg every 2 weeks. Trial registration number NCT00196742.

Pain in Fabry Disease: Practical Recommendations for Diagnosis and Treatment

Patients with Fabry disease (FD) characteristically develop peripheral neuropathy at an early age, with pain being a crucial symptom of underlying pathology. However, the diagnosis of pain is challenging due to the heterogeneous and nonspecific symptoms. Practical guidance on the diagnosis and management of pain in FD is needed.

Enzyme replacement therapy for Anderson-Fabry disease: A complementary overview of a Cochrane publication through a linear regression and a pooled analysis of proportions from cohort studies

Background Anderson-Fabry disease (AFD) is an X-linked recessive inborn error of glycosphingolipid metabolism caused by a deficiency of alpha-galactosidase A. Renal failure, heart and cerebrovascular involvement reduce survival. A Cochrane review provided little evidence on the use of enzyme replacement therapy (ERT). We now complement this review through a linear regression and a pooled analysis of proportions from cohort studies. Objectives To evaluate the efficacy and safety of ERT for AFD. Materials and methods For the systematic review, a literature search was performed, from inception to March 2016, using Medline, EMBASE and LILACS. Inclusion criteria were cohort studies, patients with AFD on ERT or natural history, and at least one patient-important outcome (all-cause mortality, renal, cardiovascular or cerebrovascular events, and adverse events) reported. The pooled proportion and the confidence interval (CI) are shown for each outcome. Simple linear regressions for composite endpoints were performed. Results 77 cohort studies involving 15,305 participants proved eligible. The pooled proportions were as follows: a) for renal complications, agalsidase alfa 15.3% [95% CI 0.048, 0.303; I2 = 77.2%, p = 0.0005]; agalsidase beta 6% [95% CI 0.04, 0.07; I2 = not applicable]; and untreated patients 21.4% [95% CI 0.1522, 0.2835; I2 = 89.6%, p<0.0001]. Effect differences favored agalsidase beta compared to untreated patients; b) for cardiovascular complications, agalsidase alfa 28% [95% CI 0.07, 0.55; I2 = 96.7%, p<0.0001]; agalsidase beta 7% [95% CI 0.05, 0.08; I2 = not applicable]; and untreated patients 26.2% [95% CI 0.149, 0.394; I2 = 98.8%, p<0.0001]. Effect differences favored agalsidase beta compared to untreated patients; and c) for cerebrovascular complications, agalsidase alfa 11.1% [95% CI 0.058, 0.179; I2 = 70.5%, p = 0.0024]; agalsidase beta 3.5% [95% CI 0.024, 0.046; I2 = 0%, p = 0.4209]; and untreated patients 18.3% [95% CI 0.129, 0.245; I2 = 95% p < 0.0001]. Effect differences favored agalsidase beta over agalsidase alfa or untreated patients. A linear regression showed that Fabry patients receiving agalsidase alfa are more likely to have higher rates of composite endpoints compared to those receiving agalsidase beta. Conclusions Agalsidase beta is associated to a significantly lower incidence of renal, cardiovascular and cerebrovascular events than no ERT, and to a significantly lower incidence of cerebrovascular events than agalsidase alfa. In view of these results, the use of agalsidase beta for preventing major organ complications related to AFD can be recommended.

Vertebrobasilar Dolichoectasia in Fabry Disease The Earliest Marker of Neurovascular Involvement

Introduction:Fabry disease (FD) is a lysosomal storage disorder associated with marked cerebrovascular involvement. Conventional magnetic resonance imaging (MRI) shows different abnormalities, like...

Determinants of white matter hyperintensity burden in patients with Fabry disease

Objective: Using a semiautomated volumetric MRI assessment method, we aimed to identify determinants of white matter hyperintensity (WMH) burden in patients with Fabry disease (FD). Methods: Patients with confirmed FD and brain MRI available for this analysis were eligible for this protocol after written consent. Clinical characteristics were abstracted from medical records. T2 fluid-attenuated inversion recovery MRI were transferred in electronic format and analyzed for WMH volume (WMHV) using a validated, computer-assisted method. WMHV was normalized for head size (nWMHV) and natural log-transformed (lnWMHV) for univariate and multivariate linear regression analyses. Level of significance was set at p < 0.05 for all analyses. Results: Of 223 patients with FD and WMHV analyzed, 132 (59%) were female. Mean age at MRI was 39.2 ± 14.9 (range 9.6–72.7) years, and 136 (61%) patients received enzyme replacement therapy prior to enrollment. Median nWMHV was 2.7 cm3 (interquartile range 1.8–4.0). Age (β 0.02, p = 0.008) and history of stroke (β 1.13, p = 0.02) were independently associated with lnWMHV. However, WMH burden—as well as WMHV predictors—varied by decade of life in this cohort of patients with FD (p < 0.0001). Conclusions: In this largest-to-date cohort of patients with FD who had volumetric analysis of MRI, age and prior stroke independently predicted the burden of WMH. The 4th decade of life appears to be critical in progression of WMH burden, as novel predictors of WMHV emerged in patients aged 31–40 years. Future studies to elucidate the biology of WMH in FD and its role as potential MRI marker of disease progression are needed.