Glycogen Storage Disease Type V (McArdle’s Disease), first described by Brian McArdle in 1951, is characterized by muscle pain, extreme fatigue, stiffness, and cramping during exercise, ultimately rendering exercise impossible. This disease is caused by mutations in the PYGM gene, located on chromosome 11q13, resulting in a dysfunctional myophosphorylase enzyme. Glycogen phosphorylase (PYG) plays a crucial role in glycogenolysis by breaking down glycogen into glucose-1-phosphate (G1P) monomers. The enzyme acts on α-1,4-glycosidic linkages, releasing glucose monomers. There are three isoforms of this enzyme: PYGB (brain), PYGL (liver), and PYGM (muscle), each with specific roles in different tissues. The study it is focused on the role of PYGM in glial cells, specifically its impact on glycogen metabolism in the brain. Glycogen serves as an important energy source in the central nervous system (CNS) and is involved in learning and memory formation, in addition to its role in energy metabolism. The breakdown product, G1P, is converted into glucose-6-phosphate (G6P) by phosphoglucomutase, which can enter glycolysis, the pentose phosphate pathway, or the hexosamine biosynthetic pathway (HBP). The HBP, which produces UDP-GlcNAc, is critical for protein modification via O-GlcNAcylation, influencing cellular processes such as glycemia balance and neuronal function. In the context of McArdle’s disease, where PYGM is inactive in glial cells, it is hypothesized that this dysfunction impairs cellular function and energy metabolism. Furthermore, N-acetylglucosamine (NAG), a substrate of the O-GlcNAc transferase (OGT) enzyme, may have potential therapeutic effects, reversing the silencing of PYGM and restoring normal cellular function. Initial experiments involved silencing PYGM expression using siRNA and analyzing glycogen deposits in astrocytes through immunohistochemistry as well as possible alterations in GFAP expression, reactive oxygen species (ROS), migration and phagocytosis. Afterwards, the experiments were conducted treating the cells with 2.5 µM NAG to study if basal functionality was restored. The results may shed light on potential therapeutic strategies for improving glycogen metabolism and cellular function in McArdle’s disease and other related conditions.