Nicola Longo MD, PhDProfessor and Vice Chair of Human Genetics,Allen and Charlotte Ginsburg Chair in Precision Genomic Medicine,Division of Clinical Genetics, Department of Human Genetics,University of California at Los Angeles (UCLA), Los Angeles, CA, USAMark Roberts, MDProfessor and Consultant Neurologist,University of Manchester, Manchester, UKResearch Lead for Adult Metabolic Medicine at Salford Care Organisation, Manchester, UKDrs. Longo and Roberts discussed the current status of gene therapies in rare neuromuscular disorders in this eight-part podcast series. This is derived from the symposium that was presented at World Symposium 2025 in San Diego, California on February 4th through 7th, 2025, and is intended for healthcare professionals only. This podcast includes information about investigational compounds that do not yet have a regulatory approval or authorization for a specific indication. The safety and efficacy of the agents under investigation have not been established and contents of this podcast shall not be used in any manner to directly or indirectly promote or sell the product for unapproved uses. The views, thoughts, and opinions expressed in this presentation belong solely to the author and are subject to change without notice. The contents of this presentation do not constitute an endorsement of any product or indication by Astellas. In this part, Dr. Longo will discuss ongoing gene therapies in lysosomal disorders.Nicola Longo MD, PhDI'm going to present to discuss some example of ongoing gene therapy for lysosomal disorder. There are gene therapy in development for both Fabry disease and some of this involve ex vivo gene therapy, many others involve systemic administration with an AAV, Gaucher disease type 1 that affect the periphery, and Gaucher disease type 2, where the replacement should occur within the central nervous system because this condition affects the brain. There is already one approved gene therapy for lysosomal disorder, which is for the early onset metachromatic leukodystrophy. This has been approved both in Europe and now even in the United States, which consists of ex vivo gene therapy with the administration of an extra gene that restore the function of the defective enzyme. Now there are many others that are ongoing for the same indication. There are gene therapy programs for GM1 and GM2 gangliosidosis, and at least one for Krabbe disease. It is important to know that some of these condition are actually included in the recommended uniform screening panel. Basically, we would have access to patients in a timely manner for some of these conditions. Then there are several gene therapy under development for the mucopolysaccharidoses, including MPS-IH, MPS-II, MPS-IIIA and MPS-IV.There are different type of lysosomal disorders, the one caused by mutation, integral membrane protein, not enzyme within the lysosome, but protein that are present on the membrane of the lysosome. This gene therapy that have been tested, it is for cystinosis, that it is caused by a defective lysosomal and for Danon disease, which is caused by a deficiency of an integral membrane part. Finally, one lysosomal disorder, which obviously seems a metabolic condition, but it is really not, is glycogen storage disease type 2 or Pompe disease, in which there is the intralysosomal accumulation of glycogen. There are several ongoing clinical trials to try to correct the problem in this condition.Now, I'm going to discuss some of the most advanced program in the lysosomal storage disorder. This include one for Fabry, which is on an accelerated approval pathway with phase 1 and 2 data, one for Gaucher disease type 1. Obviously, I'm going to discuss the one that has been already approved for metachromatic leukodystrophy. There is one for Hunter syndrome, and the difference of the one for Hunter syndrome, it is an example of the direct administration of gene therapy within the central nervous system.Finally, there is one ongoing for glycogen storage disease type 2 or Pompe disease in adult patients. In gene therapy for metachromatic leukodystrophy, it was the first gene therapy approved for lysosomal disorder in human, and this requires harvesting the CD34 cell from affected patient and then introducing the [inaudible 00:04:32] gene back in this cell, and then placing them back inside the patient again. This has been very effective in patients who were treated early, and obviously, the treatment needs to occur before there is irreversible brain damage in this patient.In the next part, Dr. Roberts and Longo will discuss treatment with gene therapies.