Clinical and laboratory observations in a child with hepatic phosphorylase kinase deficiency.

A 3-year-old child with glycogenosis due to hepatic phosphorylase kinase deficiency is described. His clinical presentation was unusually severe. Biochemical studies revealed a lack of hypoglycemia, the presence of marked ketosis and hyperlipidemia, and a normal glycemic response to glucagon and to loading with galactose, fructose, and alanine. The ketosis was reversed by glucagon administration. Changes in plasma concentrations of lactate, pyruvate, beta-OH butyrate, and alanine in response to glucagon, galactose, fructose, and alanine administration are reported. The child responded poorly to a high protein diet. His condition improved markedly with a high carbohydrate diet. The significance of the findings is discussed.