1. Background

• glycogen phosphorylase is the primary degradative enzyme of glycogen in the glycogenolytic pathway and contributes to the conversion of glycogen to lactate in the liver by disrupting the 1,4 linkages between glycosyl units
• disease first reported by Hers et al. in 1959
• inherited deficiencies of phosphorylase b kinase will produce clinical features similar to those observed in Hers Disease

2. Genetic Defect

• genetic defect -> deficiency of glycogen phosphorylase (liver) activity -> inability of hepatocytes to metabolize glycogen -> accumulation of glycogen in the liver -> hepatomegaly and hypoglycemia
• no involvement of muscle (skeletal or cardiac)

1. Liver Biopsy

• elevated liver glycogen content
• complications:
  • cirrhosis
  • adenomas and hepatomas

1. Hepatic Manifestations

2. Other Manifestations

• cherubic facies
• infantile hypotonia
• growth retardation/failure to thrive

1. Diagnostic

• deficiency of glycogen phosphorylase activity in leukocytes and samples from the liver (but not the muscle)

2. Tolerance Tests

3. Serum

• hypoglycemia
• conjugated hyperbilirubinemia
• hypertriglyceridemia, hypercholesterolemia
• variable hyperuric acidemia
• abnormal liver enzyme tests (variable transaminases)
• normal serum lactate

1. Supportive

• no treatment for underlying disease
• genetic counselling

2. Diet

• frequent high protein, low carbohydrate feeding in the first 4 years of life if hypoglycemia is a problem

3. Prognosis

• clinical features tend to improve with age
• normal life span and adult height
• normal mental development with normal onset of puberty