Phosphoglucomutase 1 (PGM1) deficiency is a rare genetic disorder that affects glycogen metabolism, glycolysis, and protein glycosylation. Previously known as GSD XIV, it was recently reclassified as a congenital disorder of glycosylation, PGM1-CDG. PGM1-CDG usually manifests as a multisystem disease. Most patients present as infants with cleft palate, liver function abnormalities and hypoglycemia, but some patients present in adulthood with isolated muscle involvement. Some patients develop life-threatening cardiomyopathy. Unlike most other CDG, PGM1-CDG has an effective treatment option, d-galactose, which has been shown to improve many of the patients' symptoms. Therefore, early diagnosis and initiation of treatment for PGM1-CDG patients are crucial decisions. In this article, our group of international experts suggests diagnostic, follow-up, and management guidelines for PGM1-CDG. These guidelines are based on the best available evidence-based data and experts' opinions aiming to provide a practical resource for health care providers to facilitate successful diagnosis and optimal management of PGM1-CDG patients.

Biochemical Genetics Laboratory Department of Laboratory Medicine and Pathology Mayo Clinic College of Medicine Rochester Minnesota USA

Center for Child and Adolescent Medicine Department University of Heidelberg Heidelberg Germany

Center for Integrative Brain Research Seattle Children's Research Institute Seattle Washington USA

Center for Metabolic Diseases KU Leuven Leuven Belgium

Centro de Genética Médica Doutor Jacinto Magalhães Unidade de Bioquímica Genética Porto Portugal

Child Neurology and Psychiatry Unit Department of Clinical and Experimental Medicine University of Catania Catania Italy

College of Medicine Alfaisal University Riyadh Saudi Arabia

Department of Clinical Genetics Institute of Clinical Medicine University of Tartu Tartu Estonia

Department of Clinical Genomics and Laboratory of Medical Pathology Mayo Clinic Rochester Minnesota USA

Department of Development and Regeneration KU Leuven Leuven Belgium

Department of Human Genetics Radboud University Medical Center Nijmegen Netherlands

Department of Inborn Errors of Metabolism and Paediatrics the Institute of Mother and Child Warsaw Poland

Department of Medical Genetics King Faisal Specialist Hospital and Research Center Riyadh Saudi Arabia

Department of Metabolic Medicine The Royal Children's Hospital Melbourne Victoria Australia

Department of Neurology Donders Institute for Brain Cognition and Behaviour Radboud University Medical Center Nijmegen the Netherlands

Department of Paediatrics and Adolescent Medicine 1st Faculty of Medicine Charles University and General University Hospital Prague Czech Republic

Department of Paediatrics and Metabolic Center University Hospitals Leuven Leuven Belgium

Department of Pediatrics Division of Human Genetics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA

Division of Genetic Medicine Department of Pediatrics University of Washington School of Medicine Seattle Washington USA

Laboratory of Hepatology Department CHROMETA KU Leuven Leuven Belgium

Metabolic Department Great Ormond Street Hospital NHS Foundation Trust and Institute for Child Health NIHR Biomedical Research Center University College London London UK

Metabolic Medicine Queensland Children's Hospital Brisbane Australia

Metabolomics Expertise Center Center for Cancer Biology VIB Leuven Belgium

Metabolomics Expertise Center Department of Oncology KU Leuven Leuven Belgium

National Human Genome Research Institute National Institutes of Health Bethesda Maryland USA

Neurology Department Hospital Sant Joan de Déu U 703 Centre for Biomedical Research on Rare Diseases Instituto de Salud Carlos 3 Barcelona Spain

Portuguese Association for Congenital Disorders of Glycosylation Lisbon Portugal

Professionals and Patient Associations International Network Lisbon Portugal

Sanford Children's Health Research Center Sanford Burnham Prebys Medical Discovery Institute La Jolla California USA

Section of Inborn Errors of Metabolism Department of Biochemistry and Molecular Genetics Hospital Clínic IDIBAPS CIBERER Barcelona Spain

UCIBIO Departamento Ciências da Vida Faculdade de Ciências e Tecnologia Universidade NOVA de Lisboa Caparica Lisbon Portugal

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