A child with recurrent hypoglycemic attack and hepatomegaly is likely to have –

Recurrent hypoglycemic attack with hepatomegaly is seen in Type I glycogen storage disease (Von Gierke disease). Glycogen storage diseases Glycogen storage diseases result from a hereditary deficiency of one of the enzymes involved in the synthesis or sequential degradation of glycogen. Clinical features depend on the type of enzyme deficiency and organ involvement. Glycogen storage diseases can be divided into:- 1)   Hepatic form (Liver glycogenolysis) The liver is the key player in glycogen metabolism. It contains enzymes that synthesize glycogen for storage and ultimately break it down into free glucose, which is then released into the blood. So, An inherited deficiency of hepatic enzymes that are involved in glycogen metabolism leads to i)  Storage of glycogen in liver → Hepatomegaly. ii) Reduction in blood glucose → Hypoglycemia. Examples of liver glycogenoses are - Type I glycogenosis → Glucose - 6 - phosphatase deficiency (Von Gierke disease). Type III glycogenosis → Debranching enzyme def Type IV glycogenesis → Branching enzyme def Type VI glycogenosis → Liver phosphorylase def 2) Myopathic form (Muscular glycogenoses) In skeletal muscle, as opposed to the liver, glycogen is used predominantly as a source of energy. This is derived from glycolysis, which leads ultimately to the formation of lactate. So, enzyme deficiency leads to - Glycogen deposition in muscle Muscle cramp after exercise The exercise-induced rise in blood lactate levels owing to block in glycolysis There may be myoglobinuria Examples are - Type V glycogenosis → phosphorylase deficiency (McArdle disease). Type VII glycogenosis → phosphofructokinase def 3) Miscellaneous types Associated with glycogen storage in many organs and death in early life. Examples - i)    Type II glycogenosis → Acid maltase deficiency (Pompe's disease)