Protein glycosylation is a crucial process involving the addition of oligosaccharides to proteins, which plays a significant role in stabilizing proteins and mediating protein-protein interactions. Mutations in genes associated with glycosylation can lead to congenital disorders of glycosylation (CDG), resulting in multisystem disorders. One such example is phosphoglucomutase 1 (PGM1) -CDG, caused by a deficiency of the PGM1 enzyme. In this report, we describe a patient with PGM1-CDG who was initially misdiagnosed with growth hormone insensitivity and benefited from recombinant human insulin-like growth factor-1 (rhIGF-1) therapy.