Glycogen storage disease due to acid maltase deficiency, late onset (AMDL), a form of Glycogen storage disease due to acid maltase deficiency (AMD), a degenerative metabolic myopathy particularly affecting respiratory and skeletal muscles, is characterized by an accumulation of glycogen in lysosomes. The disease is glycogen storage disease due to acid maltase deficiency, late-onset (MONDO_0018485, a Monarch Disease Ontology term). Also known as: Alpha-1,4-glucosidase acid deficiency, late onset, Alpha-1,4-glucosidase acid deficiency, late-onset, GSD due to acid maltase deficiency, late onset, GSD due to acid maltase deficiency, late-onset, GSD type 2, late onset, GSD type 2, late-onset, GSD type II, late onset, GSD type II, late-onset.