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In a recent publication by Klein et al., the need for real-world data on rare diseases is highlighted. We strongly support this need, and the collaboration with the patient community to collect data, as promoted in this publication. Our concern, however, is that this paper may be misunderstood as suggesting that the Sanofi-run Rare Disease Registries (RDRs) are sufficient to provide the datasets needed to evaluate current and future therapies. Industry-driven registries focus on their own product(s) and, therefore, do not provide the opportunity to compare products from different companies. Today, multiple companies produce treatments for all diseases included in the RDRs. Each company will have to run its own registry for regulatory purposes. This will lead to data fragmentation, which is prohibitive of truly understanding the effects of the various treatment options for these rare diseases. Therefore, independently funded and owned registries are essential to generate real-world evidence (RWE) unrelated to specific products. We discuss options for this for Pompe disease, including the International Pompe Survey, which has collected patient-reported outcomes independently from industry since 2002. This letter aims to raise awareness of the problem of siloed data and advocate for a new way forward where independent registries provide post-marketing surveillance data., Competing Interests: Declarations. Ethics approval and consent: Not applicable. Consent for publication: Not applicable. Competing interests: This letter was written independently of the pharmaceutical industry. Benedikt Schoser has received unrestricted research grants from Amicus, Astellas, Roche. diagnostics, Marigold Foundation, AMDA Foundation and speaker’s honoraria from Amicus Therapeutics Inc., Alexion, Kedrion and Sanofi. He has participated as a scientific advisor for Amicus, Argenx, Astellas, Bayer, Pepgen, Sanofi, Spark and Taysha. He declares no stocks or shares. Pascal Laforet has received research grants from Amicus Therapeutics Inc. and Sanofi, AMDA Foundation, Association Francophone des Glycogénoses, Vaincre les Maladies Lysosomales (VML) and speaker’s honoraria from Amicus Therapeutics Inc. and Sanofi. He has participated as a scientific advisor for Amicus Therapeutics Inc., Sanofi and Spark Therapeutics. He declares no stocks or shares. Jordi Diaz-Manera has received research grants from Spark, Sarepta, Sanofi and Boehringer Ingelheim and payments for consultancy or as speaker from Amicus Therapeutics, Astellas, Sanofi, Sarepta, Lupin and Boehringer Ingelheim and payments for consultancy or as a speaker from Amicus Therapeutics, Astellas, Sanofi, Sarepta, Lupin and Spark. He declares no stocks or shares. Ans T. van der Ploeg has acted as advisor and participated in clinical trials, registries and/or investigational projects for Amicus Therapeutics, Alexion, AskBio, Astellas, Bayer, Biogen, Biomarin, Chiesi, Denali, Dynacure, Pharming, Sarepta, Sanofi Genzyme, Ultragenix under agreements between the industry and Erasmus MC University Medical Center. Nadine A. M. E. van der Beek has participated in advisory board meetings for Sanofi and Bayer and has received speaker honoraria from Sanofi under agreements between Erasmus MC University Medical Center and the relevant industry. All other authors declare no financial or other conflicts of interest., (© 2025. The Author(s).)

Background and Purpose: The Rasch-Built Pompe-Specific Activity (R-PAct) scale is a patient-reported outcome measure specifically designed to quantify the effects of Pompe disease on daily life activities, developed for use in Dutch- and English-speaking countries. This study aimed to validate the R-PAct for use in other countries., Methods: Four other language versions (German, French, Italian, and Spanish) of the R-PAct were created and distributed among Pompe patients (≥16 years old) in Germany, France, Spain, Italy, and Switzerland and pooled with data of newly diagnosed patients from Australia, Belgium, Canada, the Netherlands, New Zealand, the USA, and the UK and the original validation cohort (n = 186). The psychometric properties of the scale were assessed by exploratory factor analysis and Rasch analysis., Results: Data for 520 patients were eligible for analysis. Exploratory factor analysis suggested that the items separated into two domains: Activities of Daily Living and Mobility. Both domains independently displayed adequate Rasch model measurement properties, following the removal of one item ("Are you able to practice a sport?") from the Mobility domain, and can be added together to form a "higher order" factor as well. Differential item functioning (DIF)-by-language assessment indicated DIF for several items; however, the impact of accounting for DIF was negligible. We recalibrated the nomogram (raw score interval-level transformation) for the updated 17-item R-PAct scale. The minimal detectable change value was 13.85 for the overall R-PAct., Conclusions: After removing one item, the modified-R-PAct scale is a valid disease-specific patient-reported outcome measure for patients with Pompe disease across multiple countries., (© 2024 The Author(s). European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Background and Purpose: Two novel enzyme replacement therapies (ERTs), studied in phase 3 trials in late-onset Pompe patients, reached marketing authorization by the European Medicines Agency in 2022 and 2023. The European Pompe Consortium (EPOC) updates and extends the scope of the 2017 recommendations for starting, switching and stopping ERT., Methods: The European Pompe Consortium consists of 25 neuromuscular and metabolic experts from eight European countries. This update was performed after an in-person meeting, three rounds of discussion and voting to provide a consensus recommendation., Results: The patient should be symptomatic, that is, should have skeletal muscle weakness or respiratory muscle involvement. Muscle magnetic resonance imaging findings showing substantial fat replacement can support the decision to start in a patient-by-patient scenario. Limited evidence supports switching ERT if there is no indication that skeletal muscle and/or respiratory function have stabilized or improved during standard ERT of 12 months or after severe infusion-associated reactions. Switching of ERT should be discussed on a patient-by-patient shared-decision basis. If there are severe, unmanageable infusion-associated reactions and no stabilization in skeletal muscle function during the first 2 years after starting or switching treatment, stopping ERT should be considered. After stopping ERT for inefficacy, restarting ERT can be considered. Six-monthly European Pompe Consortium muscle function assessments are recommended., Conclusions: The triple-S criteria on ERT start, switch and stop include muscle magnetic resonance imaging as a supportive finding and the potential option of home infusion therapy. Six-monthly long-term monitoring of muscle function is highly recommended to cover insights into the patient's trajectory under ERT., (© 2024 The Author(s). European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Background: Pompe disease is a lysosomal multisystem disorder with predominant proximal myopathy. Treatment with enzyme replacement therapy (ERT) is available requiring life-long biweekly infusions of recombinant α-glucosidase. To minimize the burden of ERT patients ask for home infusion therapy., Aims and Methods: Pompe disease experts from Germany, Austria, and Switzerland discussed in two consensus meetings in 2019 and 2020 requirements for home infusion therapy, adequate execution of treatment, and the legal situation for delegating physicians., Results and Discussion: Home infusion therapy is principally feasible for patients with Pompe disease if certain preconditions are fulfilled, but the decision to implement has to be made on an individual basis. The treating physician delegates the execution of ERT ad personam to nursing staff but retains full legal responsibility. Home infusion therapy has to be carried out by specially trained and qualified staff. Infusion-related risks comprise mainly allergic reactions, and adequate medical treatment must be warranted. In German-speaking countries, clear rules for conducting home infusion therapy are needed to reduce psychosocial stress for patients with Pompe disease, and providing legal certainty for delegating physicians., Competing Interests: Der Inhalt und Konsensus dieses Manuskripts ist unabhängig von jeglichen Industrieinteressen entstanden. Dafür garantieren alle Autoren. Die beiden Konsensus-Treffen aller Autoren (in personam) im Jahr 2019 und 2020 wurden durch die Firma Sanofi-Genzyme finanziell unterstützt. Zusätzlich fanden mehrere nicht unterstützte Telefonkonferenzen statt. Die Firma hatte keinerlei Einfluss auf den Inhalt und war weder in der Erstellung noch der Ausarbeitung des hier vorgelegten Manuskripts involviert.A. Hahn: Honorare für Teilnahme an Advisory Boards und Vorträge auf Symposien/Kongressen der Firmen Sanofi-Genzyme, Amicus, Audentes. Forschungsunterstützung durch die Firmen Sanofi-Genzyme, Shire/Takeda und AvexisC. Lampe: Honorare für Teilnahme an Advisory Boards und Vorträge auf Symposien/Kongressen der Firmen Sanofi-Genzyme, Amicus und Shire/TakedaM. Boentert: Forschungsförderung durch Sanofi-Genzyme, Löwenstein Medical, Deutsche Gesellschaft für Muskelkranke. Honorare und Kostenerstattung von Sanofi-Genzyme, Löwenstein Medical, UCB PharmaT. Hundsberger: Honorare für die Teilnahme an Advisory Boards und/oder Vorträge auf Symposien/Kongressen der Firma Sanofi-Genzyme und KedrionW. Löscher: Honorare für die Teilnahme an Advisory Boards der Firma Sanofi-GenzymeS. Wenninger: Honorare für die Teilnahme an Advisory Boards der Firma Sanofi-Genzyme und KedrionT. Schlegel: Honorar und Kostenerstattung für die Teilnahme an Advisory Boards der Firma Sanofi-GenzymeD. Ballhausen: Unrestricted research grant von Sanofi-GenzymeA. Ziegler und F. Lagler geben an, dass keine Interessenkonflikte bestehen.B. Schoser: Forschungsförderung BMBF (Bundesministerium für Bildung und Forschung), DFG (Deutsche Forschungsgemeinschaft), DGM, Sanofi-Genzyme, Amicus therapeutics, Greenovation. Honorare bzw. Kostenerstattung: Kedrion Beratertätigkeit: Amicus therapeutics, Audentes therapeutics, Lupin, Nexien, Sanofi-Genzyme, (Thieme. All rights reserved.)

Background: Late-onset Pompe disease (LOPD) is a rare autosomal recessive disorder caused by mutations in the GAA gene, leading to progressive weakness of locomotor and respiratory muscles. Enzyme replacement therapy (ERT), administered every second week, has been proven to slow down disease progression and stabilize pulmonary function. Due to the COVID-19 pandemic in Germany, ERT was interrupted at our centre for 29 days. As reports on ERT discontinuation in LOPD are rare, our study aimed to analyse the impact of ERT interruption on the change in clinical outcome., Methods: We performed a prospective cohort study in 12 LOPD patients. Clinical assessments were performed after ERT interruption and after the next three consecutive infusions. We assessed motor function by muscle strength testing, a 6-minute-walk-test, pulmonary function tests, and adverse events. For statistical analysis, an estimated baseline was calculated based on the individual yearly decline., Results: The mean time of ERT interruption was 49.42 days (SD ± 12.54). During ERT interruption, seven patients reported 14 adverse events and two of them were severe. Frequent symptoms were reduced muscle endurance/increased muscle fatigability and shortness of breath/worsening of breathing impairment. After ERT interruption, significant deterioration was found for MIP %pred (p = 0.026) and MRC %pred , as well as a trend to clinical deterioration in FVC %pred and the 6MWT %pred ., Conclusion: Interruption of ERT was associated with a deterioration in the core clinical outcome measures. Therefore, an interruption of ERT should be kept as short as possible., (© 2021. The Author(s).)

Background: Pompe disease is one of the few neuromuscular diseases with an approved drug therapy, which has been available since 2006. Our study aimed to determine the real-world long-term efficacy and safety of alglucosidase alfa., Methods: This multicenter retrospective study (NCT02824068) collected data from adult Pompe disease patients receiving ERT for at least 3 years. Demographics and baseline characteristics, muscle strength, lung function (FVC), walking capability (6MWT), and safety were assessed once a year. Evaluation was done on the group and individual levels, using quantitative linear models (t test) and general univariate linear models (ANOVA)., Findings: Sixty-eight adult Pompe disease patients from four countries (Spain, Taiwan, Italy, Germany (STIG)) participated. The mean follow-up was 7.03 years ± 2.98. At group level in all outcome measures, an initial improvement followed by a secondary decline was observed. After 10 years, the 6MWT %pred showed the most sustained positive effect (p = 0.304). The MRC %max remained stable with a mild decline (p = 0.131), however, FVC %pred deteriorated significantly (p < 0.001) by 14.93% over 10 years of ERT. The progression rate of FVC %pred under ERT could be explained in most of the patients (83.5%) by the disease severity at baseline. Furthermore, our study shows a decline in the FVC combined with an increase in non-invasive and invasive ventilation requirements in adult Pompe disease patients over time., Conclusions: The STIG real-world study confirms an initial efficacy of ERT in the first years with a secondary sustained decline in multiple outcome measures. Further efforts are required to establish a more valid long-term monitoring and improved therapies.

Background: In patients with late-onset Pompe disease, progressive respiratory muscle weakness with predominantly diaphragmatic involvement is a frequent finding at later stages of the disease. Respiratory muscle training (RMT) is an established therapy option for patients with several neuromuscular disorders including Duchenne muscular dystrophy. Forced voluntary muscle contractions of inspiration and/or expiration muscles enhance ventilation by increasing respiratory coordination, endurance, and strength. Efficacy of RMT in LOPD is rarely examined, and the clinical studies performed are difficult to compare because of different training programs and protocols. This impedes a useful statement and recommendation about the safety and efficacy of respiratory muscle training., Methods: We conducted a monocentric unblinded single-arm pilot study in patients with LOPD to evaluate the safety and efficacy of inspiratory muscle training (IMT). The primary objective was to determine the efficacy of a 6-week repetitive IMT with a gradual increase of inspiratory resistance, measured by MIP (maximum inspiratory pressure) in the upright position. For statistical analysis, we used an A-B-C single subject design. The 6-week training-period A was followed by a 6-week non-training period B and an optional training period of 40 weeks in period C. The total study duration for the periods A, B and C was 52 weeks. Throughout the study, spirometry assessments (FCV, FEV1) and measurements of respiratory strength (MIP, MEP) were performed at defined time points, as well as capillary oximetry and capnometry, motor function test and patient's questionnaires for quality of life and dyspnea, measured by St. George's Respiratory Questionnaire (SGRQ) and MMRC-Dyspnea scale. For the cross-sectional comparison, a paired two-sided t test, and for the longitudinal comparison, a two-sample, two-sided t test were used. When data were not normally distributed, a Wilcoxon-Mann-Whitney test was added. Finally, the annual decline in FVC and FEV1 before and after IMT was compared., Findings: 11 subjects were included in this pilot study. Overall, IMT was well tolerated. In four subjects, a total of six adverse events related to the study procedures were noticed. Training compliance was excellent in the first weeks of training, but declined continuously in the extension period. There was a significant increase in our primary outcome measure MIP within the 6-week period of frequent IMT with a mean of 15.7% (p =0.024; d =0.402). A significant increase was also seen after week 52 by a mean of + 26.4% (mean + 13.4 cmH 2 O, p =0.001, d =0.636). In the 6-week non-training interim-period (period B), the values remained stable, and there was no clinically meaningful decline in secondary outcome measures. The increase in MIP did not have any effect on secondary outcome measures like spirometry tests (FVC, FEV1), capillary blood gas analysis, motor function tests, patient's perceived quality of life or any significant change in dyspnea score., Conclusions: Frequent IMT improves MIP and thereby stabilizes and decelerates the decline of the diaphragm strength. The gradual increase of inspiratory resistance is well tolerated without any increase of side effects, as long as IMT is supervised and resistance is individually adjusted to the patient's perceived grade of exhaustion. Although we could not detect a significant impact on secondary outcome measures, IMT should be offered to all LOPD patients, especially to those who demonstrate a progressive decline in respiratory muscle function or are unable to receive ERT.

Pompe disease is an autosomal-recessive lysosomal storage disorder characterized by progressive myopathy with proximal muscle weakness, respiratory muscle dysfunction, and cardiomyopathy (in infants only). In patients with juvenile or adult disease onset, respiratory muscle weakness may decline more rapidly than overall neurological disability. Sleep-disordered breathing, daytime hypercapnia, and the need for nocturnal ventilation eventually evolve in most patients. Additionally, respiratory muscle weakness leads to decreased cough and impaired airway clearance, increasing the risk of acute respiratory illness. Progressive respiratory muscle weakness is a major cause of morbidity and mortality in late-onset Pompe disease even if enzyme replacement therapy has been established. Practical knowledge of how to detect, monitor and manage respiratory muscle involvement is crucial for optimal patient care. A multidisciplinary approach combining the expertise of neurologists, pulmonologists, and intensive care specialists is needed. Based on the authors' own experience in over 200 patients, this article conveys expert recommendations for the diagnosis and management of respiratory muscle weakness and its sequelae in late-onset Pompe disease., Competing Interests: Conflicts of InterestMatthias Boentert has received speaker honoraria from Genzyme GmbH, Neu-Isenburg, Germany, and Genzyme Corporation, a Sanofi Company. Hélène Prigent received speaker honoraria and travel grants from Genzyme Corporation. Harrison N. Jones has received research support and speaker honoraria from Genzyme Corporation. Katalin Várdi, Marco Confalonieri, Uwe Mellies, Anita K. Simonds, Stephan Wenninger, and Emilia Barrot Cortés declare no conflict of interest.

Background: Late-onset Pompe disease is characterized by progressive skeletal myopathy followed by respiratory muscle weakness, typically leading to loss of ambulation and respiratory failure. In this population, enzyme replacement therapy (ERT) with alglucosidase alfa has been shown to stabilize respiratory function and improve mobility and muscle strength. Muscle pathology and glycogen clearance from skeletal muscle in treatment-naïve adults after ERT have not been extensively examined., Methods: This exploratory, open-label, multicenter study evaluated glycogen clearance in muscle tissue samples collected pre- and post- alglucosidase alfa treatment in treatment-naïve adults with late-onset Pompe disease. The primary endpoint was the quantitative reduction in percent tissue area occupied by glycogen in muscle biopsies from baseline to 6months. Secondary endpoints included qualitative histologic assessment of tissue glycogen distribution, secondary pathology changes, assessment of magnetic resonance images (MRIs) for intact muscle and fatty replacement, and functional assessments., Results: Sixteen patients completed the study. After 6months of ERT, the percent tissue area occupied by glycogen in quadriceps and deltoid muscles decreased in 10 and 8 patients, respectively. No changes were detected on MRI from baseline to 6months. A majority of patients showed improvements on functional assessments after 6months of treatment. All treatment-related adverse events were mild or moderate., Conclusions: This exploratory study provides novel insights into the histopathologic effects of ERT in late-onset Pompe disease patients. Ultrastructural examination of muscle biopsies demonstrated reduced lysosomal glycogen after ERT. Findings are consistent with stabilization of disease by ERT in treatment-naïve patients with late-onset Pompe disease., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

The treatment of late-onset Pompe disease (LOPD) relies on enzyme replacement therapy (ERT) and physiotherapy but the most appropriate exercise program is not yet established. Whole-body vibration training (WBVT) has showed promising results, improving motor performances in various populations. Our aim is to assess the effects of WBVT performed by two LOPD patients in addition to ERT and physiotherapy. A side-alternating WBVT lasting 2 years; clinical assessments included: manual muscle testing (MRC sumscore), knee extension and arm flection isometric strength (multi-muscle tester M3diagnos), timed function tests (10 m walking, standing-up from chair, ascending 4-steps), 6 min walking (6 MWT), motor disability (Walton Gardner-Medwin scale), pulmonary function. Follow-up evaluations performed for 9 years since ERT start (pre-WBVT and post-WBVT) are reported for comparison. MRC sumscore improved in both patients (Pt.1:41 → 48, Pt.2:42 → 47) as isometric strength of knee extension (Pt.1: + 62 %, Pt.2: + 26 %) and arm flection (Pt.1: + 88 %, Pt.2: + 66 %), 6 MWT improved in Pt.1 (+75 m). Timed function tests did not greatly change. Patients reported no significant CK elevation or WBVT-related complaints. WBVT may be safely used in LOPD and seems to moderately boost muscle strength in patients receiving ERT and physiotherapy for more than 3 years. Larger cohorts should be studied to better assess WBVT potential as adjunctive exercise tool in LOPD.

Objective: We prospectively screened a large European cohort of patients presenting with hyperCKemia and/or limb-girdle muscular weakness (LGMW) for acid α-glucosidase (GAA) deficiency by dried blood spot (DBS) investigation., Methods: DBS were collected from 3,076 consecutive adult patients from 7 German and British neuromuscular centers. All specimens were investigated for GAA deficiency by fluorometry. Samples with reduced enzyme activity were subsequently investigated for GAA gene mutations., Results: Of 3,076 patients with DBS samples, 232 patients (7.6%) showed low GAA enzyme activity. Of these 232 patients, 55 (24%) presented with isolated hyperCKemia and 176 (76%) with hyperCKemia and LGMW. With both features present, 94% of the patients showed a low enzymatic activity. Mutational analysis found GAA gene mutations in 74 patients (2.4%); herein 70 patients were heterozygote for the common GAA gene splice-site mutation c.-32-13T>G. The most common clinical presentation in the confirmed Pompe cohort was a limb-girdle phenotype (85.3%) combined with ventilatory insufficiency (61%). Isolated hyperCKemia was found in 12%, while 2.7 had hyperCKemia and ventilatory insufficiency only., Conclusions: In a large cohort of unselected adult patients with hyperCKemia and/or LGMW, we found a prevalence of late-onset Pompe disease of 2.4%. Therefore, targeted screening of such a population should be encouraged in clinical practice., (© 2016 American Academy of Neurology.)

Homozygosity for the common Caucasian splice site mutation c.-32-13T>G in intron 1 of the GAA gene is rather rare in Pompe patients. We report on the clinical, biochemical, morphological, muscle imaging, and genetic findings of six adult Pompe patients from five unrelated families with the c.-32-13T>G GAA gene mutation in homozygous state. All patients had decreased GAA activity and elevated creatine kinase levels. Five patients, aged between 43 and 61 years (median 53 years), initially presented with myalgia, hyperCKaemia, and/or exercise induced fatigue at an age of onset (12-55 years). All but one had proximal lower limb weakness combined with axial weakness and moderate respiratory insufficiency; the sixth patient presented with hyperCKaemia only. Muscle biopsies showed PAS-positive vacuolar myopathy with lysosomal changes and reduced GAA activity. Muscle MRI of lower limb muscles revealed a moderate adipose substitution of the gluteal muscles, biceps femoris and slight fatty infiltration of all thigh muscles. One MRI of the respiratory muscles revealed a diaphragmatic atrophy with unilateral diaphragm elevation. So, the common Caucasian, so called mild, splice site mutation c.-32-13T>G in intron 1 of the GAA gene in a homozygote status reflects the full adult Pompe disease phenotype severity spectrum., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background and Purpose: Respiratory muscle weakness is the major cause of early death in patients with adult Pompe disease. It first manifests as nocturnal hypercapnia, eventually leading to sleep disruption. Sleep-related symptoms along with motor performance, forced vital capacity (FVC) and respiratory symptoms were investigated in 65 adult patients with Pompe disease., Methods: Patients answered the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale, the Fatigue Severity Scale, the Rotterdam Nine-item Handicap Scale, the SF-36 health-related quality of life questionnaire, and a respiratory symptom questionnaire. In all patients, the 6-min walk test was performed and FVC was obtained. Polysomnography and oxycapnometry results were available in 31 patients., Results: Sixty patients received enzyme replacement therapy, and 32 individuals were on home ventilatory support. Reduced sleep quality was highly prevalent (PSQI > 5; 43.1%) and correlated with both excessive daytime sleepiness (Epworth Sleepiness Scale > 10; 24.6%) and fatigue (Fatigue Severity Scale > 4; 72.3%). The SF-36 health-related quality of life questionnaire was reduced in the physical domains, and was inversely correlated with sleep quality, FVC and motor performance. In 11 out of 17 non-ventilated patients with polysomnography records, sleep-disordered breathing was present, and duration of nocturnal oxygen desaturation (SaO2 < 90%) was significantly correlated to the PSQI global score., Conclusions: In adult Pompe disease, sleep disturbances are a common cause of excessive daytime sleepiness and fatigue. Sleep-related symptoms may be indicative of respiratory muscle weakness and should give rise to further work-up of sleep-disordered breathing., (© 2014 EAN.)

Background: The obstetric risk in patients with Pompe disease (glycogen storage disease type II), a mainly skeletal muscle disorder, is unknown., Methods: The clinical course and the outcome of pregnancy, and the effect of pregnancy on disease manifestations or clinical signs and symptoms in Pompe disease were analyzed retrospectively using a questionnaire. Participating women with Pompe disease were recruited by the German and the UK sections of the International Pompe Association, and by centers associated within the German Pompe Group. The data was compared with information from the German statistical almanac, perinatal registry, and perinatal quality survey., Results: 66 of 136 women responded to the questionnaire (median age: 47 years, range: 18-74). In 10 of 52 women who had been pregnant, the symptoms of Pompe disease were present during pregnancy (n=7 1st, n=1 2nd, n=1 3rd pregnancy). Muscle weakness worsened in 3 women, and first presented in 3 others during the first pregnancy (4.5% each). Respiratory problems deteriorated in 2/10 women during pregnancy. These 10 symptomatic women had 17 pregnancies (15 deliveries, 2 miscarriages, no abortions). The 42 asymptomatic women (63.6%) had 109 pregnancies (72.4% deliveries, 19.3% miscarriages, 7.3% abortions). There were no significant differences between the mean duration of pregnancies or the mean birth weight in symptomatic and asymptomatic women, or compared to the data from the general population. The same was true of pregnancy and delivery complications (including Cesarean section)., Conclusions: Our data show that women with Pompe disease do not appear to have an increased risk of pregnancy or delivery complications. However, muscle weakness and respiratory complications might manifest or worsen during pregnancy in some women., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Pompe disease (glycogen storage disease type II, GSD II) is an autosomal recessive disease caused by a deficiency of acid α-glucosidase (GAA), leading to lysosomal glycogen accumulation in various tissues, most notably cardiac, skeletal and smooth muscle. While both infantile and late-onset patients have benefited greatly from alglucosidase alfa (Myozyme®) enzyme replacement therapy (ERT), a subgroup of patients does not demonstrate as pronounced a response as others. Various factors have been identified which may help predict the response to ERT in infantile Pompe disease patients. High, sustained antibody titers (HSAT) have been correlated with poor response to ERT in infantile Pompe cases. However, the literature on the role of antibodies in the late-onset Pompe disease (LOPD) population is limited. Our literature review highlights the need for studies to explore the potential impact of antibodies in LOPD. Further supporting the importance of this issue, our retrospective chart review of sixty LOPD patients revealed that six of these sixty (10%) LOPD patients developed HSAT of ≥1:51,200 on two or more occasions at or beyond 6 months on ERT. Here, we present a series of three of these six LOPD patients for whom detailed antibody data and clinical data were available for greater than 1 year on ERT. These three patients developed HSAT corresponding with clinical decline as demonstrated by pulmonary function, quality of life, and motor function testing, affirming the development of HSAT in a subset of patients with LOPD, and its potentially negative impact on clinical response to ERT. The findings of our study and literature review lead us to conclude that there is a strong indication for systematic studies to accurately delineate the potential impact of antibodies in LOPD., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Pompe disease (glycogen storage disease type 2 or acid maltase deficiency) is a rare autosomal recessive lysosomal storage disorder. Since the advent of ERT a lot has been learned about the phenotypic spectrum especially in the late onset patients. We describe in detail 44 patients diagnosed with late-onset Pompe disease (LOPD) at our neuromuscular department from 1985 to 2011 and compare them to patients with LOPD in the literature of the past 40 years. Study of the Munich LOPD group revealed varying musculoskeletal and cardio-cerebrovascular manifestation patterns. Several of these symptom patterns commonly appeared in conjunction with one another, highlighting the multisystem involvement of this condition. Common symptom patterns include: (i) Classic limb girdle and diaphragmatic weakness, (ii) rigid spine syndrome (RSS), scoliosis, and low body mass, and (iii) several cardio-cerebrovascular manifestation patterns. The most common presentation, limb girdle and diaphragmatic weakness, appeared in 78% (34/44) of our patients and over 80% of those in the literature. Sixteen percent (7/44) of our patients presented with rigid spine, scoliosis, and low body mass. Although scoliosis had a reported frequency of 33% in the general LOPD patient population, the literature only occasionally reported low body mass and RSS. Importantly, a multisystem extramuscular finding accompanied by cardio-cerebrovascular manifestations was found in 29% (13/44) of our LOPD patients; the literature showed an increasing prevalence of this latter finding. By examining the phenotype of patients with confirmed LOPD, we found a more subtle clinical multisystem involvement in LOPD. Whether patients presenting with the different symptom patterns respond differently to enzyme replacement therapy remains a key question for future research. © 2012 Wiley Periodicals, Inc., (Copyright © 2012 Wiley Periodicals, Inc.)

Introduction: Late-onset Pompe disease (LOPD) is highly representative for neuromuscular disorders with progressive respiratory muscle dysfunction. Non-invasive ventilation almost inevitably becomes necessary in the majority of patients, and pulmonary complications of diaphragmatic weakness are the major cause of early death in patients with LOPD. Nocturnal hypercapnia is the first sign of respiratory muscle weakness, causing sleep disruption and non-restorative sleep. We investigated sleep-related symptoms along with motor performance, respiratory symptoms, and forced vital capacity (FVC) in 60 adult patients with LOPD. Materials and methods: Patients answered the Fatigue Severity Scale (FSS), the Epworth Sleepiness Scale (ESS), the Pittsburgh Sleep Quality Index (PSQI), the Rotterdam 9-Item Handicap Scale (RHS), the SF-36 quality of life (QoL) questionnaire, and a questionnaire covering symptoms potentially indicative of respiratory muscle weakness. All patients performed the 6-min walk test (6-MWT), and FVC (upright and supine) was routinely measured. Results: LOPD was confirmed bioptically or genetically in all patients (30 female, 48.0 14.4years). 55 patients received enzyme replacement therapy, and 31 individuals were on home ventilatory support. Excessive daytime sleepiness (EDS), sleep disturbances, and fatigue were highly prevalent (ESS 10: 21.3%, PSQI 5: 41.0%, FSS 4: 68.9%). Severity of respiratory distress was significantly correlated with the ESS, FSS and PSQI scores. Fatigue was associated with reduction of supine FVC and walking distance in the 6-MWT. QoL was reduced in the physical domains, and was inversely correlated with fatigue, reduced sleep quality, disease duration, and FVC. Conclusion: In LOPD, EDS, fatigue and sleep disturbances are very common. They show association with symptoms of respiratory muscle weakness and may incidate sleep-disordered breathing. Acknowledgements: The authors are grateful to all patients who took part in this study. [Copyright &y& Elsevier]