Acid maltase deficiency or AMD is a type of autosomal recessive disorder which is characterized by an extreme buildup of glycogen contained by vacuoles (in almost all cell types) that are lysosome-derived. Quantities of free extralysosomal glycogen that are in excess have also been depicted. AMD was first observed and described by JC Pompe in 1932 at Amsterdam. He reported a case of a baby girl, aged 7 months, who became chronically ill from what they believed to be pneumonia. The autopsy that was done later showed an uncommonly engorged heart but with normal valves. This condition was called cardiomegalia glycogenica diffusa by Pompe. He considered it as a disorder that is analogous to the von Gierke syndrome. This very first article was soon followed by reports that seemed similar. The two other authors described the children as afflicted with cardiomegaly and acute muscle weakness. They died in their early infancy. Their disease was linked to an excess in the deposition of glycogen in numerous tissues. This disorder was then named the Pompe disease and by the year 1957, it was typified as type 2 glycogenosis by GT Cori.