Infantile-Onset Form

The infantile-onset form of Pompe disease typically presents rapidly within the first few months of life, often with initial observations of profound hypotonia, muscle weakness, and a "floppy baby" appearance. Feeding difficulties and respiratory problems may manifest at early stages as well.

Head-lag may be clinically observable in infantile-onset patients.

Clinical investigation usually reveals moderate hepatomegaly and sometimes macroglossia, but the hallmark sign is marked cardiomegaly with left ventricular thickening, which may result in outflow track obstruction.¹

A subset of patients with infantile-onset Pompe disease have a somewhat later age of onset (but before 12 months of age) and a slower progression of cardiomyopathy.¹

In 2001, a review of 78 infantile patients (77 of whom were less than two years old) determined the frequency of common clinical features. They found that:

96% of patients demonstrated muscle weakness
95% demonstrated cardiomegaly
82% demonstrated hepatomegaly
65% demonstrated macroglossia

In comparison, they noted that of 51 late-onset patients (24 juveniles, 27 adults), only 2% displayed cardiomegaly, underscoring the distinguishing factor of cardiac involvement in the infantile-onset form.¹

Clinical Manifestations of Infantile-Onset Pompe Disease^1,2,3,4,5

Progressive muscle weakness
Profound hypotonia
Macroglossia (and in some cases, protrusion of the tongue)
Cardiomegaly (massive)
Respiratory insufficiency/respiratory failure
Failure to meet developmental motor milestones; loss of achieved milestone
Hepatomegaly (moderate)
Difficulty swallowing, sucking, and/or feeding
Laxity of facial muscles
Areflexia

Click on the areas below to view important signs and symptoms of Pompe disease.

Disease Course

Although patients may not exhibit obvious symptoms at birth, the course of infantile-onset Pompe disease typically progresses rapidly. Spontaneous movements decline as muscle deterioration advances, and weakening of the diaphragm and other respiratory muscles is compounded by pooling secretions begins to impair respiratory function.^{2, 4}

Most patients are never able to ambulate. It is not yet known whether mental development is affected; however, data is now being collected. Death from cardiorespiratory failure usually occurs by age one.^{2, 4}

Read Late-onset >

References

1. 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, editors. The Metabolic and Molecular Bases of Inherited Disease. 8th Edition. New York: McGraw-Hill; 2001; 3389-3420.

2. 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.

3. King, Frank J. Acid Maltase Deficiency Myopathy. eMedicine Specialties. Available at: http://www.emedicine.com/pmr/topic2.htm . Accessed September 7, 2005.

4. Personal communication with Jennifer Hofstein, MS, RD, and Alfred Slonim, MD, at North Shore University Hospital Pediatric Endocrinology & Metabolism, Manhasset, New York.

5. van den Hout HMP. The natural course of infantile Pompe’s disease: 20 original cases compared with 133 cases from the literature. Pediatr 2003 Aug;112 (2): 332-340.