What are the different forms of Pompe disease?
Although Pompe disease is present at birth, the symptoms do not always occur immediately. Consequently, patients with Pompe disease are divided into two main categories, based on the age at which the first symptoms occur: the infantile form and the late form. It is estimated that one third of people born with Pompe disease have the infantile form, while the rest have the late form and start to develop signs and symptoms later in life. 
The infantile form of both forms is the worst and life-threatening. The first symptoms of the disease resurface several months after birth and those signs and symptoms usually get worse quickly, including a significantly enlarged heart. These babies are often called "floppy babies" or weak children because of their poor muscle tone and therefore they can not crawl or sit up.
Often they have difficulty to drink. In others, the diagnosis is that they have a growth disorder due to their inability to reach or maintain a healthy body weight. Due to the rapid impairment of muscles that support vital functions, these patients usually die of cardiorespiratory disorder in their first year of life, if they are not treated. [2,3,4]
Signs and symptoms of the infantile form of Pompe disease
• Severe muscle relaxation
• Enlarged tongue
• Increased heart
• Difficulty to breathe
• Inability to reach development milestones
• Enlarged liver
• Difficulty to swallow, suck and / or eat
The late form of Pompe disease can occur from childhood to later age, often with a group of symptoms that initially seem to be unrelated to each other or appear to indicate other neuromuscular diseases. Pompe disease in late form usually worsens more slowly and can vary greatly from person to person; there are patients with only mild symptoms and limited physical discomfort, while other patients eventually need a wheelchair and assistance with breathing. Generally speaking, the earlier the disease occurs, the more severe the symptoms become and the sooner the disease develops. As a result of the respiratory problems, most patients will die sooner.
- Martiniuk F, Chen A, Mack A, et al. Carrier frequency for glycogen storage diseae type II in New York and estimates of affected individuals born with the disease. Am J Med Genet 1999; 79: 69.
- Hirschhorn, Rochelle and Arnold J. J. Reuser. Glycogen Storage Disease Type II: Acid Alpha-glucosidase (Acid Maltase) Deficiency. In: Scriver C, Beaudet A, Sly W, Valle D, eds. The Metabolic and Molecular Bases of Inherited Disease. 8th Edition. New York: McGraw-Hill, 2001. 3389-3420.
- Slonim AE, Bulone L, Ritz S et al. Identification of two subtypes of infantile acid maltase deficiency. J Pediatr 2000 Aug;137(2):283-5.
- Amalfitano A, Bengur AR, Morse RP et al. Recombinant human acid alpha-glucosidase enzyme therapy for infantile glycogen storage disease type II: results of a phase I/II clinical trial. Genet Med 2001 Mar-Apr;3(2):132-8