Alglucosidase alfa enzyme replacement therapy as a therapeutic approach for a patient presenting with a PRKAG2 mutation.

Abstract

OBJECTIVE: PRKAG2 syndrome, an autosomal dominant disorder, is characterized by severe infantile hypertrophic cardiomyopathy and heart rhythm disturbances to cases with a later presentation and a spectrum of manifestations including cardiac manifestations, myopathy and seizures. The cardiac features of PRKAG2 resemble the cardiac manifestations of Pompe disease. We present a patient who was initially diagnosed with Pompe disease and treated with alglucosidase-alfa enzyme replacement therapy (ERT); however, he was eventually diagnosed to carrying a PRKAG2 pathogenic gene mutation; he did not have Pompe disease instead he was a carrier for the common adult leaky splice site mutation in the GAA gene. CASE REPORT: At 2.5months, the patient had hypotonia/generalized muscle weakness, a diagnosis of non-classic infantile Pompe disease was made based on low acid alpha-glucosidase activity and the patient started on ERT at 11months. However, 1month later, the patient began to have seizures. As the patient's medical history was somewhat unusual for infantile Pompe disease, further evaluation was initiated and included a glycogen storage disease sequencing panel which showed that the patient had a pathogenic mutation in PRKAG2 which had been reported previously. ERT was discontinued and patient had a progression of motor deficits. ERT was reinitiated by the treating physician, and a clinical benefit was noted. CONCLUSION: This report outlines the benefits of ERT with alglucosidase alfa in a patient with PRKAG2 syndrome, the decline in his condition when the ERT infusions were discontinued, and the significant positive response when ERT was reinitiated.

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Citation

Published Version (Please cite this version)

10.1016/j.ymgme.2016.09.006

Publication Info

Austin, Stephanie L, Andrew Chiou, Baodong Sun, Laura E Case, Kenny Govendrageloo, Perrin Hansen and Priya S Kishnani (2017). Alglucosidase alfa enzyme replacement therapy as a therapeutic approach for a patient presenting with a PRKAG2 mutation. Mol Genet Metab, 120(1-2). pp. 96–100. 10.1016/j.ymgme.2016.09.006 Retrieved from https://hdl.handle.net/10161/15079.

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Scholars@Duke

Sun

Baodong Sun

Associate Professor in Pediatrics

My overall research interests are finding effective treatment for human glycogen storage diseases (GSDs) and other inherited metabolic disorders. My current research focuses on identification of novel therapeutic targets and development of effective therapies for GSD II (Pompe disease), GSD III (Cori disease), and GSD IV (Andersen disease) using cellular and animal disease models. The main therapeutic approaches we are using in our pre-clinical studies include protein/enzyme therapy, AAV-mediated gene therapy, and substrate reduction therapy with small molecule drugs.

Case

Laura Elizabeth Case

Associate Professor in Orthopaedic Surgery

Laura E Case, PT, DPT, MS, PhD, PCS, C/NDT is a board-certified clinical specialist in pediatric physical therapy. She has dedicated her career to teaching, research in childhood-onset neuromusculoskeletal disorders, and to the lifelong treatment of people with childhood-onset neurological and neuromuscular disorders such as cerebral palsy, traumatic brain injury, Duchenne muscular dystrophy, spinal muscular atrophy, Pompe disease, myelodysplasia, juvenile rheumatoid arthritis, and brachial plexus injury.

She has been involved in numerous clinical trials for the treatment of disorders including Pompe disease and other metabolic disorders, cerebral palsy, Duchenne muscular dystrophy, and spinal muscular atrophy. Dr. Case has participated in the development of international guidelines for the management of Duchenne muscular dystrophy, Pompe disease, and other glycogen storage diseases.

She teaches and consults internationally, has worked on a number of Center for Disease Control (CDC) task forces, has served on numerous committees and task forces in the pediatric section of APTA, served two terms as NC State Representative to the APTA Section on Pediatrics, and is a member of the North American Pompe Registry Board of Advisors.

Kishnani

Priya Sunil Kishnani

Chen Family Distinguished Professor of Pediatrics

RESEARCH INTERESTS

A multidisciplinary approach to care of individuals with genetic disorders in conjunction with clinical and bench research that contributes to:
1) An understanding of the natural history and delineation of long term complications of genetic disorders  with a special focus on liver Glycogen storage disorders, lysosomal disorders with a special focus on Pompe disease, Down syndrome and hypophosphatasia
2) ) The development of new therapies such as AAV gene therapy, enzyme therapy, small molecule and other approaches for genetic disorders through translational research

3) The development and execution of large multicenter trials to confirm safety and efficacy of potential therapies
4) Role of antibodies/immune response in patients on therapeutic proteins and AAV gene therapy

. Glycogen Storage Disease (GSD): We are actively following subjects with all types of Glycogen Storage Disease, with particular emphasis on types I, II, III, IV, VI and IX. The goal of the treatment team is to better determine the clinical phenotype and long term complications of these diseases. Attention to disease manifestations observed in adulthood, such as adenomas and risk for HCC, is of paramount importance in monitoring and treating these chronic illnesses. We are establishing clinical algorithms for managing adenomas, and the overall management of these patients including cardiac, bone, muscle and liver issues. A special focus is biomarker discovery, an Omics approach including metabolomics and immune phenotyping. We are working on AAV gene therapy for several hepatic GSDs

.Lysosomal Storage Disease: The Duke Lysosomal Storage Disease (LSD) treatment center follows and treats patients with Pompe, Gaucher, Fabry, Mucopolysaccharidosis, Niemann Pick, LAL-D and other LSD's. The Duke Metabolism Clinical Research Team is exploring many aspects of enzyme replacement therapy (ERT), including impact on different systems, differential response, and long term effects. Other symptomatic and treatment interventions for this category of diseases are also being explored in the context of clinical care.

. Pompe Disease: The care team has extensive experience in the care of infants and adults with Pompe disease and was instrumental in conducting clinical trials and the bench to bedside work that led to the 2006 FDA approval of alglucosidase alfa, the first treatment for this devastating disease. We are currently focusing on role of antibodies/immune response on patient outcome and role of immune modulation/immune suppression as an adjunct to ERT. Our team is also working on AAV gene therapy for Pompe disease. A focus is on newborn screening (NBS) and understanding the clinical phenotype and management approaches for babies identified via NBS

.  Hypophosphatasia: We follow a large cohort of patients with HPP. The goal is to understand the features of the disease beyond bone disease, development of biomarkers, role of ERT and immune responses in HPP

. Neuromuscular disorders: We are collaborating with neurologists, cardiologists and neuromuscular physicians to serve as a treatment site for clinical trials in these diseases. We are currently involved in trials of DMD and are working closely on setting up collaborations for studies in SMA.


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