Glycogen Storage Diseases

A group of autosomal recessive (inherited from both parents) diseases caused by missing enzymes in the process of breaking down glycogen in the body.  The symptoms vary greatly according to the missing enzyme.  Some types can be fatal.  Type O causes an enlarged liver with an accumulation of fat inside the liver cells.  It can also affect various muscles.  Type 1A, or Von Gierke’s disease, causes enlargement of the liver and kidney, slowed growth, and exceptionally low blood sugar levels.  It can also cause abnormally high levels of acids, fats, and uric acid in the blood.  Type 1B causes a low white blood count, affecting the liver and kidneys.  Recurring infections in the mouth and intestines may lead to Crohn’s disease, an inflammatory disease of the intestines.  Type 2, or Pompe’s disease, affects all organs.  Type 3, or Forbe’s disease, causes an enlarged liver, low blood sugar levels, and heart and muscle damage.  Type 5,, or McArdie’s disease, causes muscle cramps when engaged in physical activity.  Type 6, or Her’s disease, often show no symptoms, but may enlarge the liver when fasting due to episodes of low blood sugar.  Type 7, or Tarui’s disease, affects skeletal muscles and red blood cells.  Treatment for all the above is usually by controlling dietary intake.