GSD Type 0

Type 0

Other Names Hepatic glycogen synthase deficiency

Defect Deficiency in hepatic glycogen synthase (an enzyme critical for normal glycogen synthesis)

Signs & Symptoms :

• High blood ketones, low blood sugar during fasting ( usually on cessation of nighttime feeding)
• High glucose, high lactic acid after meals- particularly in the morning (may lead to confusion with diabetes)

Cause:

Inherited autosomal-recessive manner resulting from mutations in GYS2 gene located on chromosome 12p12.2. Affects both genders equally.

Diagnosis:

• Should be considered when monitoring shows a unique metabolic disturbance characterized by alternating fasting hypoglycemia (low blood sugar), hyperketonemia( elevated blood ketones) followed by hyperglycemia (high blood sugar) and hyperlacticacidemia (elevated lactic acid) with feeding.
• Liver biopsy showing hepatocytes (liver cells) that contain only small amounts of glycogen with moderate steatosis (abnormal fat deposits within the cells).
• Mutation analysis (gold standard)

Treatment The goal of treatment is to prevent hypoglycemia by avoiding fasting. Frequent meals and snacks can be given every 3-4 hours during the day. Uncooked cornstarch will prevent hypoglycemia overnight. A diet with an increased amount of protein is recommended since extra carbohydrates are shunted to lactic acid.