McArdle's disease is a metabolic myopathy characterized by a myophosphorylase deficiency resulting in an inability to degrade glycogen stores. We report the case of a 48 years old patient who complained since adolescence of rest and exercise myalgias and presented a chronic increased plasma creatine kinase activity. First, a maximal exercise test was performed. This test demonstrated a quasi lack of rise of respiratory exchange ratio and of blood lactate, possibly due to a glycogenolytic/glycolytic pathway deficiency. Second, a biopsy of vastus lateralis muscle was performed using Bergström needle. As expected, the analysis of mitochondrial function was normal. The in vitro screening test of the glycogenolysis/glycolysis pathway showed a lack of lactate production in presence of glycogen substrate. The study of muscular metabolism of glycogen revealed a glycogen accumulation and a decrease of active and total phosphorylase activities. These data allowed us to diagnose a type V glycogenosis, or McArdle's disease. The patient appeared heterozygous for the most frequent mutation (p.R50X).
Download full-text PDF |
Source |
---|
Cureus
December 2024
Internal Medicine, Hospital Conde de Bertiandos, Unidade Local de Saúde do Alto Minho, Ponte de Lima, PRT.
McArdle disease is a rare myopathy caused by hereditary myophosphorylase deficiency. It presents nonspecific symptoms, such as intolerance to physical exercise, early fatigue, and myalgias, and represents a paradigmatic example of one of the main challenges in clinical practice: the recognition of nonspecific and common symptoms as clinically relevant manifestations of rare diseases. The nonspecificity of symptoms leads to a frequent delay from the onset of first clinical signs to diagnosis.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Immunology, School of Medicine, UConn Health, Farmington, CT 06030.
Monocytes are critical in controlling tissue infections and inflammation. Monocyte dysfunction contributes to the inflammatory pathogenesis of cystic fibrosis (CF) caused by CF transmembrane conductance regulator (CFTR) mutations, making CF a clinically relevant disease model for studying the contribution of monocytes to inflammation. Although CF monocytes exhibited adhesion defects, the precise mechanism is unclear.
View Article and Find Full Text PDFCase Rep Rheumatol
January 2025
Department of Rheumatology, Royal Wolverhampton NHS Trust, Wolverhampton, UK.
McArdle disease or glycogen storage disease Type V is a genetic condition caused by PYGM gene mutations leading to exercise intolerance and fatigability. The condition most commonly presents in childhood. In rare cases, patients have presented with late-onset McArdle disease.
View Article and Find Full Text PDFRheumatol Immunol Res
December 2024
Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
Disabil Rehabil
November 2024
Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!