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 Orphanet rare-disease nomenclature entry Orphanet_308604 (Glycogen storage disease due to acid maltase deficiency, adult onset). Also known as: Alpha-1,4-glucosidase acid deficiency, adult onset, GSD due to acid maltase deficiency, adult onset, GSD type 2, adulte onset, Glycogen storage disease type 2, adult onset, Glycogenosis due to acid maltase deficiency, adult onset, Glycogenosis type 2, adult onset, Pompe disease, adult onset, glycogen storage disease ii, adult form.