Years Of Enzyme Replacement Therapy Research Articles

Use of T1 mapping in cardiac MRI for the follow-up of Fabry disease in a pediatric population

BackgroundFabry disease (FD) is a rare X-linked lysosomal disorder caused by pathogenic variants in the alpha-galactosidase-A gene (GLA). Life threatening complications in adulthood include chronic kidney failure, strokes and the cardiac involvement which is the leading cause of mortality. Usually, it presents with hypertrophic cardiomyopathy, together with arrhythmia and conduction abnormalities. An early indicator is decreased T1 value on cardiac magnetic resonance (CMR). Enzyme replacement therapy (ERT) is effective on some extra-cardiac symptoms but its effect on cardiac lesions depends on the level of initial myocardial lesions. CMR is routinely used to monitor cardiac involvement in FD due to its capacity for tissular characterization. However, there is a lack of data on the pediatric population to understand how to integrate CMR into early therapeutic decisions. MethodMonocentric longitudinal study carried out at Montpellier University Hospital from 2016 to 2022. All pediatric patients with FD were evaluated over time with clinical, biological, and cardiac imaging (CMR, echocardiography). ResultsOut of the six patients included, (3 males), five were treated with ERT during the study. Low T1 values were observed in 4 patients. The normalization of T1 values was observed after 4 years of ERT in 3 patients. ConclusionDue to the lack of strong clinical and biological markers of FD in pediatric patients, initiation and follow-up of ERT efficacy remain challenging. CMR with T1-mapping, a noninvasive method, could play a role in the evaluation of early cardiac impairment in young patients at diagnosis and during follow-up with or without ERT.

Velaglucerase alfa for treatment in children with Gaucher disease type 1: the Russian experience

The current gold standard for the treatment of Gaucher disease type 1 in children is enzyme replacement therapy. The efficacy and safety of treatment with velaglucerase alfa have been assessed in only a few large studies involving pediatric patients as subjects of research. In the Russian literature, there are no data available on the use of velaglucerase alfa in drug-naïve patients with Gaucher disease type 1. The aim of our study was to assess the efficacy and safety of treatment with velaglucerase alfa in children with Gaucher disease type 1. The study was approved by the Independent Ethics Committee and the Scientific Council of the National Medical Research Center for Children's Health of Ministry of Healthcare of the Russian Federation. All patients and/or their legal representatives gave their informed consent to the study. The efficacy of treatment with velaglucerase alfa in children with Gaucher disease type 1 was assessed by analyzing monitoring data of 15 patients aged 2 to 15 years who had been registered in the Russian Pediatric Gaucher Registry established at National Medical Research Center for Children's Health of Ministry of Healthcare of Russia over the period from 2015 to 2023. None of the patients had ever undergone enzyme replacement therapy before they were included in this study. The median age at the start of treatment was 6.5 years. We analyzed the patients' anthropometric, laboratory and instrumental data at 0, 6, 12, 24 and 36 months. The initial dose of enzyme replacement therapy ranged from 30 to 60 units/kg (with the median of 43 units/kg per infusion) once every 2 weeks based on disease severity. In as little as 6 months after the initiation of therapy with velaglucerase alfa, patients with Gaucher disease type 1 showed a statistically significant improvement in all measured parameters (p < 0.001): normalization of the median hemoglobin concentration and platelet count (from 113 to 125 g/L and from 111 to 163 × 109/L, respectively); a reduction in degree of liver and spleen enlargement (in terms of volume, from 45.1 to 17.9% and from 39.4 to 15.5%, respectively); a reduction in degree of the right liver lobe enlargement (in terms of linear measurements, from 27.2 to 11.1%); a reduction in degree of spleen enlargement (in terms of its length and width, from 73.4 to 37.8% and from 60.3 to 17.5%, respectively). Our patients had a remarkable decrease in biomarker activity after 3 years of therapy: chitotriosidase activity decreased from 2699 to 227 nmol/mL/h and glucosylsphingosine level was reduced from 204.0 to 35.3 ng/mL (р < 0.001). There were no adverse events during the course of treatment. After 6 months and 1 year of regular enzyme replacement therapy with appropriate doses of velaglucerase alfa initiated in a timely manner, children with Gaucher disease type 1 achieve normal hemoglobin concentrations and platelet counts, a reduction in biomarker activity, and a decrease in liver and spleen volumes. After 3 years of enzyme replacement therapy, patients achieve their main therapeutic goals such as the resolution of anemia and thrombocytopenia, an almost complete regression of hepatosplenomegaly and the normalization of bone mineral density and height adjusted for age.

Systems analyses of the Fabry kidney transcriptome and its response to enzyme replacement therapy identified and cross-validated enzyme replacement therapy-resistant targets amenable to drug repurposing

Fabry disease is a rare disorder caused by variations in the alpha-galactosidase gene. To a degree, Fabry disease is manageable via enzyme replacement therapy (ERT). By understanding the molecular basis of Fabry nephropathy (FN) and ERT's long-term impact, here we aimed to provide a framework for selection of potential disease biomarkers and drug targets. We obtained biopsies from eight control individuals and two independent FN cohorts comprising 16 individuals taken prior to and after up to ten years of ERT, and performed RNAseq analysis. Combining pathway-centered analyses with network-science allowed computation of transcriptional landscapes from four nephron compartments and their integration with existing proteome and drug-target interactome data. Comparing these transcriptional landscapes revealed high inter-cohort heterogeneity. Kidney compartment transcriptional landscapes comprehensively reflected differences in FN cohort characteristics. With exception of a few aspects, in particular arteries, early ERT in patients with classical Fabry could lastingly revert FN gene expression patterns to closely match that of control individuals. Pathways nonetheless consistently altered in both FN cohorts pre-ERT were mostly in glomeruli and arteries and related to the same biological themes. While keratinization-related processes in glomeruli were sensitive to ERT, a majority of alterations, such as transporter activity and responses to stimuli, remained dysregulated or reemerged despite ERT. Inferring an ERT-resistant genetic module of expressed genes identified 69 drugs for potential repurposing matching the proteins encoded by 12 genes. Thus, we identified and cross-validated ERT-resistant gene product modules that, when leveraged with external data, allowed estimating their suitability as biomarkers to potentially track disease course or treatment efficacy and potential targets for adjunct pharmaceutical treatment.

Egyptian Gaucher disease type 3 patients: a large cohort study spanning two decades

BackgroundGaucher disease (GD) has been the subject of genotype/phenotype studies as well as therapeutic innovation. A cohort of ethnically homogeneous Egyptian patients suffering from GD type 3 (GD3) is described here, with the effects of enzyme replacement therapy (ERT) highlighted.MethodsWe studied the long-term outcome after 20 years of ERT in 85 patients with GD3 registered at the Pediatric Hematology Clinic of Cairo University since 1998. We obtained organ volumes, growth parameters, and neurological assessment at baseline and during ERT.ResultsOf the total sample, 77.6% of patients were diagnosed before the age of 2 years. Our patients were highly consanguineous, and 51% had a family history of GD. The most prevalent genotype was homozygous p.Leu483Pro (75.7%), followed by homozygous p.Asp448His (11%). Hemato-visceral aspects of disease included anemia (75.6%), moderate to severe thrombocytopenia (21.7%), severe splenomegaly (49.2%), and severe hepatomegaly (10.8%). One patient had liver cirrhosis with hepatopulmonary syndrome. Oculomotor apraxia, squint, and bulbar symptoms were reported in 48.6%, 30.6%, and 29.4% of patients, respectively. Imiglucerase (Cerezyme) was administered to all patients for reversal of hemato-visceral and growth parameters. The overall survival rate was 71% at 20 years; 20 patients died of pulmonary and neurological diseases.ConclusionThis is the largest single-center study of GD3 patients with predominant homozygous p.Leu483Pro genotype. The patients had a very early onset of disease and severe disease parameters. The renunciation of hemato-visceral disease was achieved effectively by ERT with 71% OS, and one third of patients developed complications.

Long-term effectiveness of enzyme replacement therapy in Fabry disease with the p.Arg227Ter variant: Fabry disease in Ostrobothnia (FAST) study.

Fabry disease (FD) is an X chromosome-linked, life-threatening lysosomal disease caused by one of more than 1000 currently known variants in the α-galactosidase A (GLA) gene. The follow-up part of the Fabry Disease in Ostrobothnia (FAST) study reports the long-term effect of enzyme replacement therapy (ERT) on a prospectively collected cohort of 12 patients, 4 males and 8 females, mean age 46 years (SD 16), with the classical variant c.679C > T p.Arg227Ter, which is one of the most common FD variants worldwide. In the natural history period of the FAST study, half of the patients in both sexes had at least one major event, of which 80% were of cardiac origin. During 5 years of ERT, four patients had a total of six major clinical events consisting of one silent ischemic stroke, three ventricular tachycardias and two increased left ventricular mass indexes. In addition, four patients developed minor cardiac events, four patients minor renal events, and one patient a minor neurological event. ERTs may delay but not prevent the progression of the disease in most patients with the variant Arg227Ter. This variant might be suitable for investigating the efficacy of second-generation ERTs compared to the currently used ERTs regardless of sex.

Association between changes in pulmonary function and in patient reported outcomes during enzyme therapy of adult patients with late-onset Pompe disease".

Pompe disease is a rare, progressive, metabolic myopathy. Reduced pulmonary function is one of the main problems seen in adult patients with late-onset Pompe disease (LOPD). We aimed to explore the association between changes over time in pulmonary function and in patient-reported outcome measures (PROMs), in these patients treated with enzyme replacement therapy (ERT). This is a post-hoc analysis of two cohort studies. Pulmonary function was assessed as Forced Vital Capacity in the upright position (FVCup ). As PROMs, we assessed the physical component summary score (PCS) of the Medical Outcome Study 36-item Short-Form Health Survey (SF-36) and daily life activities (Rasch-Built Pompe-Specific Activity [R-PACT] scale). We fitted Bayesian multivariate mixed-effects models. In the models of PROMs, we assumed a linear association with FVCup , and adjusted for time (non-linear), sex, and age and disease duration at the start of ERT. One hundred and one patients were eligible for analysis. PCS and R-PAct were positively associated with FVCup , while their relation with time was non-linear (initial increase then decrease). A 1%-point increase in FVCup is expected to increase PCS by 0.14 points (95% Credible Interval: [0.09;0.19]) and R-PACT by 0.41 points [0.33;0.49] at the same time point. In the first year of ERT, we expect a change of PCS and R-PAct scores by +0.42 and + 0.80 points, and in the 5th year of +0.16 and + 0.45, respectively. We conclude that the physical domain of quality of life and daily life activities improve when FVCup increases during ERT.

Effects of enzyme replacement therapy on cardiac function in classic infantile Pompe disease

ObjectivePatients with classic infantile Pompe disease are born with a hypertrophic cardiomyopathy, which resolves after treatment with Enzyme replacement therapy (ERT). We aimed to assess potential deterioration of cardiac function over time using myocardial deformation analysis. MethodsTwenty-seven patients treated with ERT were included. Cardiac function was assessed at regular time intervals (before and after start with ERT) using conventional echocardiography and myocardial deformation analysis. Separate linear mixed effect models were used to asses temporal changes within the first year and the long-term follow-up period. Echocardiograms of 103 healthy children served as controls. ResultsA total of 192 echocardiograms were analyzed. Median follow-up was 9.9 years (IQR: 7.5–16.3). Mean LVMI before start of ERT was increased 292.3 g/m2 (95% CI: 202.8–381.8, mean Z-score + 7.6) and normalized after 1 year of ERT 87.3 g/m2 (CI: 67.5–107.1, mean Z-score + 0.8, p < 0.001). Mean shortening fraction was within normal limits before start of ERT, up to 22 years of follow-up. Cardiac function measured by RV/LV longitudinal, and circumferential strain was diminished before start of ERT, but normalized (<−16%) within 1 year after start of ERT, and all remained within normal limits during follow-up. Only LV circumferential strain gradually worsened in Pompe patients (+0.24%/year) during follow-up compared to controls. LV longitudinal strain was diminished in Pompe patients, but did not change significantly over time compared to controls. ConclusionCardiac function, measured using myocardial deformation analysis, normalizes after start of ERT, and seems to remain stable over a median follow-up period of 9.9 years.

Late-onset and classic phenotypes of Fabry disease in males with the GLA-Thr410Ala mutation

ObjectiveTo present phenotypic characteristics and biomarkers of a family with the rare mutation Thr410Ala of the α-galactosidase A gene (T410A/GLA) causing Fabry disease (FD).Methods and resultsIn a woman in her...

Enzyme replacement therapy for children with acid sphingomyelinase deficiency in the real world: A single center experience in Taiwan

BackgroundAcid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease with multi-systemic involvement, with no disease-modifying treatment available. Olipudase alfa is an investigational enzyme product developed to replace the deficient acid sphingomyelinase in ASMD patients. Several clinical trials have reported promising safety and efficacy results in adult and pediatric patients. However, no data have been reported outside of the clinical trial setting yet. This study aimed to evaluate major outcomes in pediatric chronic ASMD patients receiving olipudase alfa in the real-world setting. Materials and methodsTwo children with type A/B (chronic neuropathic) ASMD have received olipudase alfa treatment since May 2021. Clinical parameters, including height, weight, complete blood count, liver function tests, lipid profiles, biomarkers, abdominal ultrasonography with shear wave elastography, chest computed tomography, nerve conduction studies, neurodevelopmental evaluations, and six-minute walk tests, were checked at baseline and every three to six months in the first year of enzyme replacement therapy (ERT) to assess its efficacy and safety. ResultsThe two patients in our study started olipudase alfa treatment at the age of 5 years and 8 months and 2 years and 6 months. During the first year of treatment, both patients saw a reduction in their hepatic and splenic volumes as well as liver stiffness. Height z-score, weight z-score, lipid profiles, biomarker levels, interstitial lung disease scores, and bone mineral densities also improved over time. The six-minute walk test showed a gradual increase in walking distance in both patients. There were no obvious improvements or deterioration in neurocognitive function and peripheral nerve conduction velocities after treatment. No severe infusion-associated reactions were noted during the first year of treatment. One patient had two episodes of transient but significantly elevated liver enzymes during the dose-escalation phase. The patient was asymptomatic, and the impaired liver function resolved spontaneously within two weeks. ConclusionOur results provide real-world experience that olipudase alfa is safe and effective in improving major systemic clinical outcomes for pediatric chronic ASMD patients. Monitoring of liver stiffness by shear wave elastography is a noninvasive procedure that can monitor treatment efficacy during ERT.

Effect of Anti-Iduronate 2-Sulfatase Antibodies in Patients with Mucopolysaccharidosis Type II Treated with Enzyme Replacement Therapy

To assess the relationship between anti-Iduronate 2-sulfatase (IDS) antibodies, IDS genotypes, phenotypes and their impact in patients with enzyme replacement therapy (ERT)-treated Mucopolysaccharidosis type II. Dutch patients treated with ERT were analyzed in this observational cohort study. Antibody titers were determined by enzyme-linked immunosorbent assay. Neutralizing effects were measured in fibroblasts. Pharmacokinetic analysis of ERT was combined with immunoprecipitation. Urinary glycosaminoglycans were measured using mass spectrometry and dimethylmethylene blue. Eight of 17 patients (47%) developed anti-IDS antibodies. Three patients with the severe, neuronopathic phenotype, two of whom did not express IDS protein, showed sustained antibodies for up to 10years of ERT. Titers of 1:5120 or greater inhibited cellular IDS uptake and/or intracellular activity invitro. In 1 patient who was neuronopathic with a titer of 1:20 480, pharmacokinetic analysis showed that all plasma recombinant IDS was antibody bound. This finding was not the case in 2 patients who were not neuronopathic with a titer of 1:1280 or less. Patients with sustained antibody titers showed increased urinary glycosaminoglycan levels compared with patients with nonsustained or no-low titers. Patients with the neuronopathic form and lack of IDS protein expression were most at risk todevelop sustained anti-IDS antibody titers, which inhibited IDS uptake and/or activity invitro, and the efficacy of ERT in patients by lowering urinary glycosaminoglycan levels.

Divergent Impact of Enzyme Replacement Therapy on Human Cardiomyocytes and Enterocytes Affected by Fabry Disease: Correlation with Mannose-6-phosphate Receptor Expression.

Background: The impact of enzyme replacement therapy (ERT) on cardiomyocytes and intestinal cells, affected by Fabry disease (FD), is still unclear. Methods: Six patients with FD, including five family members with GLA mutation c.666delC and one with GLA mutation c.658C > T, manifesting cardiomyopathy and intestinal symptoms (abdominal pain, diarrhea and malabsorption) were included in the study. Clinical outcome, cardiac magnetic resonance (CMR), endomyocardial and gastro-intestinal biopsies were evaluated before and after 2 years of treatment with agalsidase-α (0.2 mg/kg every other week). Immunohistochemistry and Western blot assessments of mannose-6-phosphate receptors (IGF-II-R) on intestinal and myocardial frozen tissue were obtained at diagnosis and after 2 years of ERT. Results: After ERT left ventricular maximal wall thickness, ranging from pre (<10.5 mm) to mild (<15 mm) and moderate hypertrophy (16 mm), was not associated with significant changes at CMR. Degree of dyspnea, mean cardiomyocyte diameter and % vacuolated areas of cardiomyocytes, representing intracellular GL3, remained unmodified. In contrast, intestinal symptoms improved with disappearance of diarrhea, recovery of anemia and weight gain, correlating with near complete clearance of the enterocytes from GL3 inclusions. IGF-II-R expression was remarkably higher even at histochemistry in intestinal tissue compared with myocardium (p < 0.001) either at baseline and after ERT, thus justifying intestinal recovery. Conclusions: Human cells affected by FD may respond differently to ERT: while cardiomyocytes retain their GL3 content after 2 years of treatment, gastro-intestinal cells show GL3 removal with recovery of function. This divergent response may be related to differences in cellular turnover, as well as tissue IGF-II-R expression.

Fifteen years of enzyme replacement therapy for mucopolysaccharidosis type VI (Maroteaux\u2013Lamy syndrome): a case report

BackgroundMucopolysaccharidosis VI, or Maroteaux–Lamy disease, is an autosomal recessive disease characterized by deficiency of the enzyme arylsulfatase B in the lysosomal catabolism of glycosaminoglycans. Due to reduced (or even null) enzyme activity, glycosaminoglycans (mainly dermatan sulfate) accumulates, leading to a multisystemic disease. Mucopolysaccharidosis VI induces reduced growth, coarse face, audiovisual deficits, osteoarticular deformities, and cardiorespiratory issues, hampering the quality of life of the patient. Enzyme replacement therapy with galsulfase (Naglazyme, BioMarin Pharmaceuticals Inc., USA) is the specific treatment for this condition. Although studies have shown that enzyme replacement therapy slows the progression of the disease, the effects of long-term enzyme replacement therapy remain poorly understood.Case presentationA 29-year-old, Caucasian, male patient diagnosed with mucopolysaccharidosis VI was treated with enzyme replacement therapy for over 15 years. Enzyme replacement therapy was initiated when patient was 13 years old. The patient evolved multiplex dysostosis, carpal tunnel syndrome, thickened mitral valve, and hearing and visual loss.ConclusionsAlthough enzyme replacement therapy did not prevent the main signs of mucopolysaccharidosis VI, it slowed their progression. Additionally, enzyme replacement therapy was associated with a longer survival compared with the untreated affected sibling. Taken together, the results indicate that enzyme replacement therapy positively modified the course of the disease.

Cerebrospinal fluid neurofilament light chain levels in CLN2 disease patients treated with enzyme replacement therapy normalise after two years on treatment

Classic late infantile neuronal ceroid lipofuscinosis (CLN2 disease) is caused by a deficiency of tripeptidyl-peptidase-1. In 2017, the first CLN2 enzyme replacement therapy (ERT) cerliponase alfa (Brineura) was approved by the FDA and EMA. The CLN2 disease clinical rating scale (CLN2 CRS) was developed to monitor loss of motor function, language and vision as well as frequency of generalised tonic clonic seizures. Using CLN2 CRS in an open label clinical trial it was shown that Brineura slowed down the progression of CLN2 symptoms. Neurofilament light chain (NfL) is a protein highly expressed in myelinated axons. An increase of cerebrospinal fluid (CSF) and blood NfL is found in a variety of neuroinflammatory, neurodegenerative, traumatic, and cerebrovascular diseases. We analysed CSF NfL in CLN2 patients treated with Brineura to establish whether it can be used as a possible biomarker of response to therapy. Newly diagnosed patients had CSF samples collected and analysed at first treatment dose and up to 12 weeks post-treatment to look at acute changes. Patients on a compassionate use programme who were already receiving ERT for approximately 1yr had CSF samples collected and NfL analysed over the following 1.3 years (2.3 years post-initiation of ERT) to look at long-term changes. All newly diagnosed patients we investigated with classical late infantile phenotype had high NfL levels >2000 pg/ml at start of treatment. No significant change was observed in NfL up to 12 weeks post-treatment. After one year of ERT, two out of six patients still had high NfL levels, but all patients showed a continued decrease, and all had low NfL levels after two years on ERT. NfL levels appear to correspond and predict improved clinical status of patients on ERT and could be useful as a biomarker to monitor neurodegeneration and verify disease modification in CLN2 patients on ERT.

Clinical-genetic characteristics and treatment outcomes of Turkish children with Gaucher disease type 1 and type 3: A sixteen year single-center experience

Data from 38 children were retrospectively analyzed to determine the patient characteristics of Turkish children with Gaucher disease (GD) and evaluate the impact of enzyme replacement therapy (ERT) in a pediatric cohort consisting of two different sub-types of the disease, Gaucher disease type 1 (GD1) and type 3 (GD3). Both types were represented equally (GD1/GD3 = 20/18). L444P (35.5%) was the most common mutant allele while L444P/L444P (34.2%) was the most common genotype overall. Compound heterozygosity of N370S and L444P homozygosity were the dominant genotypes in Turkish children with GD1 and GD3, respectively. None of the patients had moderate to severe thrombocytopenia at last follow-up while the percent of patients with anemia decreased from 60% to 5.7% (p < 0.001). Significant improvements in mean liver (from 2.2 to 1.6 MN, p < 0.001) and spleen (from 15.5 to 7.6 MN, p < 0.001) volumes were observed in the first year of ERT. Linear growth was ameliorated as shown by the decrease in the percent of patients having short stature from 34.3% to 13.3% (p < 0.01) at year 5. Erlenmeyer flask deformity, osteopenia and scoliosis were common skeletal findings. Although none of the patients had lung disease at diagnosis, 20% developed radiological findings suggestive of pulmonary involvement. This single center experience is the first comprehensive study from Turkey not only reporting clinical and genetic characteristics of GD patients but also providing information on the outcomes of ERT in two different sub-types of GD. Genotypic background of Turkish children with GD is similar to western populations. Although visceral and hematological therapeutic goals are reached as early as one year of ERT in both sub-types, achieving normal growth takes several more years than suggested in significant number of children with GD.

Inhibition of Epigenetic Reader BET Proteins by Apabetalone Counters Inflammation in Activated Innate Immune Cells from Fabry Disease Patients Receiving ERT

Abstract Fabry disease (FD) is a rare genetic disorder with a deficit in the degradation pathway of a glycolipid, globotriaocylceramide (Gb3). Gb3 deposits in various tissues evoke immune-mediated systemic inflammation, driving the progression of FD complications. In particular, cardiac and renal problems, leading causes of mortality in FD patients, are insufficiently managed by enzyme replacement therapy (ERT) in the long term. Here, we examined immune profiles in unstimulated peripheral blood mononuclear cells (PBMCs) from FD patients on ERT relative to untreated patients. The results showed an upregulation of the CCR2/MCP-1 axis, particularly in the presence of renal dysfunction. We also observed an increase of IL12B transcripts in unstimulated PBMCs when tracking the immune status over two years of ERT in patients with early-stage chronic kidney disease (CKD). Interestingly, pro-inflammatory responses in LPS-stimulated PBMCs were countered by apabetalone, a clinical-stage candidate that inhibits Bromodomain and Extra Terminal (BET) proteins, epigenetic readers. Apabetalone treatment dose dependently inhibited MCP-1 and IL-12 production by up to 90%. Apabetalone downregulated the transcription of other pro-inflammatory cytokines including TNF-α, IL-6 and IL-8 by 70%, 48% and 54%, respectively. Reactive oxygen species (ROS) are an indicator of oxidative damage caused by intracellular Gb3 deposits in FD patients. Apabetalone suppressed ROS levels by up to ~70% in LPS-stimulated neutrophils. Hence, apabetalone treatment may reduce pathological inflammation and oxidative stress in FD patients and thus complement ERT to optimize patient outcomes, warranting further investigation of apabetalone as a therapeutic for FD.

Muscle Proteomic Profile before and after Enzyme Replacement Therapy in Late-Onset Pompe Disease

Mutations in the acidic alpha-glucosidase (GAA) coding gene cause Pompe disease. Late-onset Pompe disease (LOPD) is characterized by progressive proximal and axial muscle weakness and atrophy, causing respiratory failure. Enzyme replacement therapy (ERT), based on recombinant human GAA infusions, is the only available treatment; however, the efficacy of ERT is variable. Here we address the question whether proteins at variance in LOPD muscle of patients before and after 1 year of ERT, compared withhealthy age-matched subjects (CTR), reveal a specific signature. Proteins extracted from skeletal muscle of LOPD patients and CTR were analyzed by combining gel based (two-dimensional difference gel electrophoresis) and label-free (liquid chromatography-mass spectrometry) proteomic approaches, and ingenuity pathway analysis. Upstream regulators targeting autophagy and lysosomal tethering were assessed by immunoblotting. 178 proteins were changed in abundance in LOPD patients, 47 of them recovered normal level after ERT. Defects in oxidative metabolism, muscle contractile protein regulation, cytoskeletal rearrangement, and membrane reorganization persisted. Metabolic changes, ER stress and UPR (unfolded protein response) contribute to muscle proteostasis dysregulation with active membrane remodeling (high levels of LC3BII/LC3BI) and accumulation of p62, suggesting imbalance in the autophagic process. Active lysosome biogenesis characterizes both LOPD PRE and POST, unparalleled by molecules involved in lysosome tethering (VAMP8, SNAP29, STX17, and GORASP2) and BNIP3. In conclusion this study reveals a specific signature that suggests ERT prolongation and molecular targets to ameliorate patient’s outcome.

Effect of long term enzyme replacement therapy in late onset Pompe disease: A single-centre experience

Late onset Pompe disease (LOPD) is a slowly progressive metabolic myopathy with variable clinical severity. The advent of enzyme replacement therapy (ERT) has modified the natural course of the disease, though the treatment effect on adult patients is modest compared to infants with the classic form. This study aims to describe the long-term clinical outcome of the Greek LOPD cohort, as assessed by 6 min walk test, muscle strength using MRC grading scale and spirometry. ERT efficacy was estimated using statistical methodology that is novel in the context of Pompe disease, which at the same time is well-suited to longitudinal studies with small samples and missing data (local non-linear regression analysis). Improvement over baseline was significant at 1 year for motor performance and muscle strength (p < 0.05), and at 2 years for FVC-U and FVC-S (p < 0.05). A subgroup analysis showed that the onset of the disease before adulthood (18 years), a male gender, and a latency of more than 2 years between the onset of symptoms and ERT administration are unfavorable prognostic factors. Conclusively, this study presents longitudinal data from the Greek LOPD cohort supporting previous observations, that therapeutic delay is related to worse prognosis and treatment effects may decline after several years of ERT.

Largest Cohort Study of Gaucher Disease Type 3 from a Single Center in Egypt Spanning Two Decades

Background and objectives:Gaucher disease (GD) is renowned for genotype/phenotype studies and therapeutic innovation. However, the vast majority of the literature is focused on Type 1 GD related to the founder mutation, p.Asn409Ser in GBA gene although p.Leu483Pro GBA mutation associated GD may be far more prevalent across the world. In Egypt GD represents as high as 14.7% of all reported lysosomal disorders with the neuronopathic forms. Therefore, a large single center cohort study of a highly consanguineous GD population has the potential to inform genotype/phenotype, natural history studies and illuminate unmet needs. Methods:At University of Cairo's Pediatric Hematology Clinic since 1998, we have managed a total of 156 patients with GD with longitudinal data captured under an approved IRB protocol. In the present study, we focused analysis on 85 patients in whom we had long-term outcome after 20 years of enzyme replacement therapy (ERT). GBA gene analysis was performed by whole exome sequencing of DNA isolated from dry blood spots. Data on the clinical phenotype indicators at baseline and during ERT were collected including liver and spleen volumes, growth parameters, bone status, neurological assessment and eye movement. SPSS (Statistical Package for the Social Sciences) version 24 was used to compile data, assess significance and survival by Kaplan Meier analysis. Overall survival (OS) is defined as date of diagnosis till date of death, patients alive or lost during follow up was considered censored till the last date of follow up. Results:The median age at diagnosis was 1 year (IQR: 0.08-15 years) with majority (64.7%) diagnosed in first 2 years of life (range 0.5-2 yrs). The patient population was highly consanguineous and 51% of the patients reported positive family history of GD. The most prevalent genotype (75% of patients) was p.Leu483Pro homozygous. Homozygosity for p.Asp448His was present in 11% of patients. Other GBA mutations included: p.Leu483Pro homozygous in 3 patients, one heteroallelic with p.Leu483Pro; pArg87Trp homozygous in 2 patients; p.Arg398Gln homozygous in one patient). Hematological features of patients at diagnosis revealed anemia in 76% and thrombocytopenia in 22%. Massive splenomegaly (˃15 Multiples of Normal by ultrasonography) was present in 49%, 4 patients were splenectomised, hepatomegaly (˃2.5 MN) in 11%, liver cirrhosis with hepatopulmonary syndrome in one patient. Skeletal findings included multiple fractures in 3 patients and kyphosis in 3 patients. The most common neurological findings were oculomotor apraxia, squint and bulbar symptoms (48%, 30.6% and 29.4% respectively). Bone marrow examination showed Gaucher cell infiltration in 76% of the patients. Patients received Imiglucerase (Cerezyme) dose individualized by baseline disease severity. Debilitating and potentially life-threatening visceral and hematologic disease was reversed with ERT (table 1). One splenectomized patient with massive hepatomegaly and hepatopulmonary syndrome showed complete reversal on high dose ERT. Preliminary observer reported outcomes (by clinician and parent) with respect to neurological findings including oculomotor apraxia appeared to show mild improvement. Follow-up of 10 patients in whom ERT was initiated early had striking overall outcomes progressing through school and university. At 20 years, the overall survival was 71%; 20 patients died from disease complications mostly pulmonary and progressive neurological disease. Comparison of the OS in relation to gender, age at diagnosis, severity of hematological and visceral parameters showed that none of the studied variables affects OS (p˃0.05) (fig. 1). Conclusion:This study represents the largest and most extensive single-center cohort of GD3 patients with predominant p.Leu483Pro homozygous GBA genotype, without presence of a complex allele. Patients had uniformly very early-onset disease before age 2 years with devastating hematological and visceral disease which was effectively reversed by ERT. During 20 year-follow up of the cohort, there was striking reversal of hematovisceral disease and about a third of the patients succumbed to complications of GD3. OS was not correlated with severity of baseline disease underscoring the potential role of modifier genes. Disclosures No relevant conflicts of interest to declare.

Body composition and 6 minute walking ability in late-onset pompe disease patients after 9 years of enzyme replacement therapy

Objective Pompe disease is a rare autosomal recessive disorder caused by the deficiency of acid α-glycosidase resulting in accumulation of glycogen in the lysosomes. The late-onset form of the disease (LOPD) causes primarily progressive muscle weakness and respiratory insufficiency. Enzyme replacement therapy (ERT) introduced in 2006, showed mild improvement or stabilization of the symptoms although long-term data are limited. Aim of the study was to describe the progression of body composition and walking ability in LOPD patients receiving ERT consistently for 9 years. Methods Lean body mass, bone mineral density, body fat and 6 min walking distance were assessed in three male and three female LOPD patients (height 165.8 ± 11.2 cm, age 42.3 ± 11.8yrs, body mass 71.1 ± 20.8 kg, at study entry), every three years, for 9 years since ERT initiation (T0, T3, T6, T9). Results Total body and upper extremities’ lean mass remained unchanged (p < 0.05), but it was decreased for the lower extremities (T3:13.06 ± 3.848 kg vs. T9:11.63 ± 3.49 kg, p < 0.05). Lean body mass was not significantly different after 9 years of ERT compared to before the ERT initiation (T0 to T9). Bone mineral density remained unchanged. Percent body fat increased (T0:39.1 ± 10.3%, vs. T9:43.1 ± 10.4%, p < 0.05). Six minute walking distance tended to increase after 3 years of ERT and decreased gradually thereafter, with no difference between T0-T9. Lean mass of the lower extremities adjusted for body weight was significantly correlated with 6 min walking distance (r = 0.712, p < 0.05). Conclusion The current data show that enzyme replacement therapy may preserve lean body mass, bone mineral density and walking capacity in LOPD patients.

Natural history of untreated patients with type 1 Gaucher disease

Data from 38 children were retrospectively analyzed to determine the patient characteristics of Turkish children with Gaucher disease (GD) and evaluate the impact of enzyme replacement therapy (ERT) in a pediatric cohort consisting of two different sub-types of the disease, Gaucher disease type 1 (GD1) and type 3 (GD3). Both types were represented equally (GD1/GD3 = 20/18). L444P (35.5%) was the most common mutant allele while L444P/L444P (34.2%) was the most common genotype overall. Compound heterozygosity of N370S and L444P homozygosity were the dominant genotypes in Turkish children with GD1 and GD3, respectively. None of the patients had moderate to severe thrombocytopenia at last follow-up while the percent of patients with anemia decreased from 60% to 5.7% (p < 0.001). Significant improvements in mean liver (from 2.2 to 1.6 MN, p < 0.001) and spleen (from 15.5 to 7.6 MN, p < 0.001) volumes were observed in the first year of ERT. Linear growth was ameliorated as shown by the decrease in the percent of patients having short stature from 34.3% to 13.3% (p < 0.01) at year 5. Erlenmeyer flask deformity, osteopenia and scoliosis were common skeletal findings. Although none of the patients had lung disease at diagnosis, 20% developed radiological findings suggestive of pulmonary involvement. This single center experience is the first comprehensive study from Turkey not only reporting clinical and genetic characteristics of GD patients but also providing information on the outcomes of ERT in two different sub-types of GD. Genotypic background of Turkish children with GD is similar to western populations. Although visceral and hematological therapeutic goals are reached as early as one year of ERT in both sub-types, achieving normal growth takes several more years than suggested in significant number of children with GD.