GTR Home > Conditions/Phenotypes > Glycogen storage disease, type II

Disease characteristics

Excerpted from the GeneReview: Glycogen Storage Disease Type II (Pompe Disease)
Glycogen storage disease type II (GSD II), or Pompe disease, is classified by age of onset, organ involvement, severity, and rate of progression. Classic infantile-onset Pompe disease may be apparent in utero but more often presents in the first two months of life with hypotonia, generalized muscle weakness, cardiomegaly and hypertrophic cardiomyopathy, feeding difficulties, failure to thrive, respiratory distress, and hearing loss. Without treatment by enzyme replacement therapy (ERT), classic infantile-onset Pompe disease commonly results in death in the first year of life from progressive left ventricular outflow obstruction. The non-classic variant of infantile-onset Pompe disease usually presents within the first year of life with motor delays and/or slowly progressive muscle weakness, typically resulting in death from ventilatory failure in early childhood. Cardiomegaly can be seen, but heart disease is not a major source of morbidity. Late-onset (i.e., childhood, juvenile, and adult-onset) Pompe disease is characterized by proximal muscle weakness and respiratory insufficiency; clinically significant cardiac involvement is uncommon in the late-onset form.

Associated genes

Clinical features

  • Fever
  • Cardiomegaly
  • Splenomegaly
  • EEG abnormalities
  • Areflexia
  • Irregular heart beat
  • EMG abnormality
  • Shortened PR interval
  • Respiratory insufficiency due to muscle weakness
  • Gait disturbance
  • Firm muscles
  • Cognitive impairment
  • Recurrent respiratory infections
  • Seizure
  • Wolff-Parkinson-White syndrome
  • Feeding difficulties in infancy
  • Abnormality of the tongue
  • Macroglossia
  • Hearing impairment
  • Muscular hypotonia
  • Hypertrophic cardiomyopathy
  • Dyspnea
  • Emphysema
  • Neurological speech impairment
  • Hepatomegaly
  • Myopathy
  • Elevated serum creatine phosphokinase
  • Proximal muscle weakness
  • Cerebral aneurysm
  • Type II diabetes mellitus
  • Diaphragmatic paralysis
  • Aplasia/Hypoplasia of the abdominal wall musculature
  • Abnormal CNS myelination
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