Minimal clinically important differences in six-minute walking distance in late-onset Pompe disease

BACKGROUND

The minimal clinically important difference (MCID) is the smallest change in outcome that physicians or patients would consider meaningful and is relevant when evaluating disease progression or the efficacy of interventions. Studies of patients with late-onset Pompe disease (LOPD) have used the 6-min walk distance (6MWD) as an endpoint to assess motor function. However, an MCID for 6MWD (% predicted and meters) has yet to be established in LOPD. The objective of the study was to derive 6MWD MCID (% predicted and meters) with different analysis methods and for subgroups of different disease severity for LOPD.

METHODS

Data from the PROPEL trial were used to calculate 6MWD MCID in the overall PROPEL population and subgroups of baseline severity as assessed by walking distance and body mass index (BMI), using anchor- and distribution-based approaches.

RESULTS

The 6MWD MCIDs varied widely, depending on the method and subgroup, ranging from 2.27%-8.11% predicted for the overall LOPD population (23.7 m-57.2 m). For patients with baseline 6MWD < 150 m, MCIDs ranged from -0.74%-3.37% (-2.1 m-11.3 m). MCIDs increased with distance walked at baseline until a plateau was reached. For BMI subgroups, the MCIDs were generally lowest in obese patients.

CONCLUSION

Our analysis shows that MCID depends on the chosen method and disease severity. The findings suggest that applying a single MCID to all patients can be misleading; consequently, a range of possible MCIDs should be considered. This may also be highly relevant for other neuromuscular diseases. This study provides a range of 6MWD MCIDs for LOPD, with lower MCIDs for more severe patients.

Long-Term Outcome of Infantile Onset Pompe Disease Patients Treated with Enzyme Replacement Therapy - Data from a German-Austrian Cohort

BACKGROUND

Enzyme replacement therapy (ERT) with recombinant human alglucosidase alfa (rhGAA) was approved in Europe in 2006. Nevertheless, data on the long-term outcome of infantile onset Pompe disease (IOPD) patients at school age is still limited.

OBJECTIVE

We analyzed in detail cardiac, respiratory, motor, and cognitive function of 15 German-speaking patients aged 7 and older who started ERT at a median age of 5 months.

RESULTS

Starting dose was 20 mg/kg biweekly in 12 patients, 20 mg/kg weekly in 2, and 40 mg/kg weekly in one patient. CRIM-status was positive in 13 patients (86.7%) and negative or unknown in one patient each (6.7%). Three patients (20%) received immunomodulation. Median age at last assessment was 9.1 (7.0-19.5) years. At last follow-up 1 patient (6.7%) had mild cardiac hypertrophy, 6 (42.9%) had cardiac arrhythmias, and 7 (46.7%) required assisted ventilation. Seven patients (46.7%) achieved the ability to walk independently and 5 (33.3%) were still ambulatory at last follow-up. Six patients (40%) were able to sit without support, while the remaining 4 (26.7%) were tetraplegic. Eleven patients underwent cognitive testing (Culture Fair Intelligence Test), while 4 were unable to meet the requirements for cognitive testing. Intelligence quotients (IQs) ranged from normal (IQ 117, 102, 96, 94) in 4 patients (36.4%) to mild developmental delay (IQ 81) in one patient (9.1%) to intellectual disability (IQ 69, 63, 61, 3x <55) in 6 patients (54.5%). White matter abnormalities were present in 10 out of 12 cerebral MRIs from 7 patients.

CONCLUSION

Substantial motor, cardiac, respiratory, and cognitive deficits are frequent in IOPD long-term survivors who started ERT before 2016. The findings of this study can be valuable as comparative data when evaluating the impact of newer treatment strategies including higher enzyme dosage, immunomodulation, modified enzymes, or early start of treatment following newborn screening.

Characterization of neuromuscular performances in adults with late-onset Pompe disease: A control case cross-sectional study

Adults with late-onset Pompe disease (aLOPD) are characterized by muscular contractile tissue deterioration. However, their neuromuscular performances are poorly known. We aimed to compare maximal muscle strength, activation, explosive strength and neuromuscular fatigue between aLOPD and controls. We studied 20 aLOPD and 20 matched controls. Isometric maximum voluntary contraction (MVC) torque was obtained for the hip, knee and ankle muscles. The voluntary activation level (VAL) during knee extensor MVC was assessed using interpolated twitch technique. Explosive strength was evaluated for knee and ankle muscles through the rate of torque development (RTD) during fast contractions. Neuromuscular fatigue was measured during a 30-second contraction of knee flexors and extensors. All muscle MVC torques were significantly lower in aLOPD than controls (p <0.05). The weakest muscles were the hip extensors followed by hip abductors and abductors. Raw value of RTD was lower in aLOPD for the majority of muscles (p <0.05). No intergroup differences were reported for normalized RTD, VAL and neuromuscular fatigue (p-values> 0.05). Our study shows that maximal strength was the only neuromuscular characteristic affected in aLOPD with a proximal-distal intensity gradient. This suggests that the surviving muscle tissue of aLOPD is as functionally efficient as that of control individuals.

Safety outcomes and patients' preferences for home-based intravenous enzyme replacement therapy (ERT) in pompe disease and mucopolysaccharidosis type I (MPS I) disorder: COVID-19 and beyond

BACKGROUND

The Italian Medicines Agency (AIFA) demands precise information on benefit/risk profile of home-based enzyme replacement therapy (ERT) for the treatment of patients with Pompe disease and Mucopolysaccharidosis type I (MPS I). This passage is necessary to obtain the authorization for ERT home therapy, even after the coronavirus disease-19 (COVID-19) pandemic period. This research intends to evaluate the safety, treatment satisfaction, and compliance of MPS I patients treated with laronidase (Aldurazyme®) and Pompe Disease patients treated with alglucosidase alfa (Myozyme®) in a homecare setting.

RESULTS

We report herein an early interim analysis of the HomERT (Home infusions of ERT) study, a multicenter, non-interventional, double-cohort study that retrospectively analyzed 38 patients from 14 sites in Italy: cohort A (Pompe disease - 32 patients) and cohort B (MPS I - 6 patients). Among the selected patients who started home therapy before enrollment, the average number of missed home-based infusions was 0.7 (1.3) in cohort A and 3.8 (6.4) in cohort B with no return to the hospital setting. Irrespective of the treatment location, 3 prior ADRs per cohort were reported. The majority of patients preferred home-based infusions (cohort A: 96.9%; cohort B: 100%): the main reason was attributed to treatment convenience (cohort A: 81.3%; cohort B: 83.3%). Despite the underlying conditions, most patients self-evaluated their health as "good" (cohort A: 50%; cohort B: 83.3%).

CONCLUSIONS

Evidence of favorable safety profile, improved treatment compliance and personal satisfaction validates the use of ERT with laronidase and alglucosidase alfa as a strong candidate for home therapy.

Anaesthetic implications for Pompe disease. A case description

Pompe disease, or type II glycogenosis, is a rare metabolic myopathy inherited in an autosomal recessive pattern, characterized by progressive muscle weakness and multisystem involvement. The disease often results in premature death. Patients with Pompe disease are at high risk for anaesthesia-related complications, particularly cardiac and respiratory problems, although difficult airway management is the greatest complication. It is essential to perform a comprehensive preoperative study in order to reduce the risk of perioperative morbidity and mortality, and to obtain as much information as possible for the surgical procedure. In this article, we report the case of a patient with a history of adult Pompe disease who underwent combined anaesthesia for osteosynthesis of the proximal end of the left humerus.

Genome-Wide Association Studies Reveal Candidate Genes Related to Stem Diameter in Cucumber (Cucumis sativus L.)

The stem diameter, an important agronomic trait, affects cucumber growth and yield. However, no genes responsible for cucumber stem diameter have been identified yet. In this study, the stem diameter of 88 cucumber core germplasms were measured in spring 2020, autumn 2020 and autumn 2021, and a genome-wide association study (GWAS) was carried out based on the gene sequence and stem diameter of core germplasms. A total of eight loci (gSD1.1, gSD2.1, gSD3.1, gSD3.2, gSD4.1, gSD5.1, gSD5.2, and gSD6.1) significantly associated with cucumber stem diameter were detected. Of these, five loci (gSD1.1, gSD2.1, gSD3.1, gSD5.2, and gSD6.1) were repeatedly detected in two or more seasons and were considered as robust and reliable loci. Based on the linkage disequilibrium sequences of the associated SNP loci, 37 genes were selected. By further investigating the five loci via analyzing Arabidopsis homologous genes and gene haplotypes, five genes (CsaV3_1G028310, CsaV3_2G006960, CsaV3_3G009560, CsaV3_5G031320, and CsaV3_6G031260) showed variations in amino acid sequence between thick stem lines and thin stem lines. Expression pattern analyses of these genes also showed a significant difference between thick stem and thin stem lines. This study laid the foundation for gene cloning and molecular mechanism study of cucumber stem development.

Assessment of the function and morphology of the thyroid gland in paediatric patients treated with enzyme replacement therapy due to selected storage diseases - preliminary results of our own research and a review of the literature

INTRODUCTION

Some storage diseases, caused by a deficiency of a specific enzyme, which results in the systemic accumulation of non-metabolized substances, can be treated with enzyme replacement therapy (ERT), which can protect many organs, including the endocrine system.

AIM

The aim of the study was to assess the function and morphology of the thyroid gland in children with storage diseases treated with ERT, and to review the literature.

MATERIAL AND METHODS

Eight patients were included in the study: 3 with Fabry disease (age: 17; 9.9; 10 years), 3 with Hunter's disease (12.3; 4.1; 9,3), and 2 with Pompe disease (6.8; 9,5). Thyroid function and morphology were assessed in each patient during ERT, and 4 of them were reassessed 27 months later.

RESULTS

One patient with Fabry disease had been treated for hypothyroidism due to autoimmune thyroiditis diagnosed before the study. The remaining patients had normal thyroid tests and negative anti-thyroid antibodies at first and second evaluation; however, in all reassessed patients a decrease in TSH value was noted. Among the remaining patients with Fabry disease, one had normal and a second had heterogeneous echogenicity of the thyroid during first assessment. In the second patient, normalisation of echogenicity was observed at reassessment. Both patients with Pompe disease assessed once had slightly heterogeneous thyroid echogenicity. In 3 patients with Hunter's disease in the first ultrasound examination, no abnormalities were found. In re-evaluation, 2 of them showed heterogeneous thyroid echogenicity.

CONCLUSIONS

We conclude that patients with storage diseases should undergo assessment of thyroid function and morphology before and during ERT.

A 2-Year-Old Child with Late-Onset Pompe Disease: a Case Report

BACKGROUND

Pompe disease is an inherited neuromuscular disease caused by a deficiency of lysosomal acid alphaglucosidase (GAA) leading to glycogen accumulation in muscle and motor neurons.

METHODS

We retrospectively collected the clinical information on the case of a 2-year-old child admitted to the emergency department with respiratory failure and generalized hypotonia.

RESULTS

Chest radiograph, cerebral and spinal magnetic resonance imaging, muscle biopsy, etc. were all examined. The 2-year-old child was later diagnosed with Pompe disease. Systematic assessment and effective sedation management were applied.

CONCLUSIONS

Differential diagnosis, systematic assessment, and effective sedation management are important for Pompe disease patients.

Treating lysosomal storage disorders: What have we learnt?

The first enzyme replacement therapy (ERT) for a lysosomal storage disorder (LSD) was approved in 1991 and we now have more than 25 years of experience of treating patients with type 1 Gaucher disease. Because of the remarkable success of this therapy, enormous effort and resource has gone into developing other ERTs, for Gaucher (where three different enzyme preparations have now been approved) and for other LSDs. We now have more than 10 years of clinical experience in using ERT to treat Gaucher, Fabry, Pompe and MPS I, II, and VI. This article aims to assess the real-life experience of a selection of these innovative and expensive treatments to see if they have met the high expectations which were set for them when they launched.

The Role of Disaccharidase Deficiencies in Functional Abdominal Pain Disorders-A Narrative Review

Disaccharidase deficiencies are reportedly underdiagnosed in pediatric populations. Though typically thought to cause diarrheal disease, they can also be a cause of abdominal pain and dyspepsia, and patients diagnosed with these functional disorders may actually have associated enzyme deficiencies. While the effects of lactose deficiency have been widely studied, sucrase, maltase, and isomaltase are less frequently considered when approaching a patient with an apparent functional abdominal pain disorder. This review seeks to provide an up-to-date narrative on the current scientific literature on the possible role of sucrase, maltase, and isomaltase deficiency in pediatric functional gastrointestinal disorders.

Successful combined liver/kidney transplantation from a donor with Pompe disease

Pompe disease results from inherited deficiency of the enzyme acid alpha-glucosidase resulting in lysosomal accumulation of glycogen primarily in skeletal muscle. Reported is the first case in which a donor with late onset Pompe disease (LOPD) was successfully used for deceased donor liver and kidney transplantation. This case demonstrates co-operative transplant surgery and genetic medicine evaluation and risk estimation for donors with inherited metabolic disorders some of which may be suitable for donation of selected organs for transplantation.

Use of Polylactide-Co-Glycolide-Nanoparticles for Lysosomal Delivery of a Therapeutic Enzyme in Glycogenosis Type II Fibroblasts

Glycogenosis type II, or Pompe Disease, is a lysosomal storage disease caused by the deficiency of acid alpha-glucosidase (GAA), leading to glycogen accumulation in muscles. A recombinant human GAA (rhGAA, Myozyme®) is currently used for enzyme replacement therapy. Despite its efficacy in most of patients, some of them show a diminished response to the treatment with rapidly progressive clinical deterioration, due to immuno-mediated enzyme inactivation. To demonstrate that Nanoparticles (NPs) could be profitably exploited to carry macromolecules, PLGA NPs loaded with rhGAA (GAA-NPs) were prepared by double emulsion solvent evaporation. Their surface morphology, particle size, zeta-potential and biochemical activity were assessed. "Pulse and chase" experiments were made by administrating GAA-NPs on patients' fibroblasts. Biochemical activity tests showed a more efficient cellular uptake of rhGAA loaded to NPs and a more significant stability of the enzyme (up to 7 days) in vitro, if compared to the same amount of rhGAA free enzyme. This data allows to envision in vivo experiments, in significant animal models, to further characterize lysosomal enzyme loaded-NPs' efficacy and toxicity.

Development of a disease-specific disability instrument for Pompe disease

PURPOSE

The purpose of this study was to modify the Paediatric Evaluation of Disability Inventory (PEDI) to create a Pompe disease-specific disability instrument for use in clinical trials and natural history studies.

METHODS

PEDI item content was revised to include self-care and mobility items appropriate for children and youth with Pompe disease. Data were collected on 30 individuals with Pompe disease (mean age 7.7+/-5.6 years; range 0.4-22.1 years) by parent proxy through telephone interviews. New items were merged with original PEDI items using Rasch rating scale methods.

RESULTS

The Pompe-PEDI extended the content range and scoring precision of the original PEDI. Construct validity was demonstrated and test-re-test reliability was excellent.

CONCLUSIONS

The Pompe-PEDI is a reliable and valid instrument to assess and monitor the functional changes of children and youth with Pompe disease.

[Congenital enzyme deficiency in carbohydrate metabolism. Its significance for clinical pediatrics and human biochemical genetics (author's transl)]

A review of the enzyme deficiencies of carbohydrate metabolism known at the present time is given. Through prominent clinical symptoms and consideration of food as a pathological agent, it is possible to suspect the various diseases before the results of the biochemical determinations are available. On account of the sometimes striking course, therapy can consequently be started at the earliest possible moment.

Glycogen-Storage Disease

A case of glycogen-storage disease (Coritype II), with accumulation of glycogen in the myocardium, skeletal muscle, smooth muscle, liver, kidney, central nervous system, and autonomic ganglia is presented.

Glycogen storage in the autonomic ganglia of the intestinal tract (Plexus-myentericus-Auerbach), which gave rise clinically to Hirschsprung's disease, could explain the feeding problems and constipation often observed in these cases.

The classification into four different types of Cori and Andersen appears to be the most satisfactory one at the present time. These types are different disease entities with the same expression of abnormality, the deposition of glycogen; but the pathogenesis and the clinical and pathologic findings are strikingly different.

Glycogen storage of the heart is probably more common than the review of the literature indicates. Many of these cases are missed, mainly types III and IV, because the possibility is not considered and the patient is inadequately studied in life and during necropsy.