Ans. D. Glucose-6-phosphatase. (Ref. Harper Biochemistry 26th /pg.152; Table 19-2; H-18th/Table 362-1)Features of Glycogen Storage Diseases and Galactose and Fructose Disorders.Type/ Common NameBasic DefectCommentsLiver GlycogenosesDisorders with hepatomegaly and hypoglycemiala/von GierkeGlucose-6-phosphataseGrowth retardation, enlarged liver and kidney, Severe fasting hypoglycemia, elevated blood lactate, cholesterol, triglycerides, and uric acid, glycogen in liver.Common, severe hypoglycemia, Complications in adulthood include hepatic adenomas, hepatic carcinoma, renal failure.Rx: Autosomal recessive. Treatment: frequent oral glucose/cornstarch; avoidance of fructose and galactose.IbGlucose-6-phosphate translocaseAs for la, with additional findings of neutropenia and neutrophil dysfunction. 10% of type I.IIIa/Cori or ForbesLiver and muscle debranching enzyme (alpha 1-6-glucosidase)Childhood: Hepatomegaly, growth retardation, muscle weakness, hypoglycemia, hyperlipidemia, elevated liver transaminases; liver symptoms improve with ageAdulthood: muscle atrophy and weakness; onset: third to fourth decades; variable cardiomyopathy. Milder form of typel Gycogen storage disorder with normal blood lactate levels; Autosomal recessive. Gluconeogenesis is intact. Hepatic adenomas, liver cirrhosis, and hepatoma can occurVI/HersLiver phosphorylaseHepatomegaly, variable hypoglycemia, hyperlipidemia and ketosis; symptoms may improve with age. Rare, often a "benign" -glycogenosis, severe cases being recognizedIX/phosphorylase kinase deficiencyLiver phosphorylase kinase a subunitAs for VI. Common, X-linked, typically less severe than autosomal forms; clinical variability within and between subtypes; severe cases being recognizedO/glycogen synthase deficiencyGlycogen synthaseFasting hypoglycemia and ketosis, elevated lactic acid and hyperglycemia after glucose load. Decreased glycogen storesXI/ Fanconi-BickelGlucose transporter-2Failure to thrive, rickets, hepatomegaly, proximal renal tubular dysfunction, impaired glucose and galactose utilization. Rare, consanguinity in 70%Disorders with liver cirrhosisIV/AndersenBranching enzymeFailure to thrive, hypotonia, hepatomegaly, splenomegaly, progressive liver cirrhosis and failure (death usually before fifth year); some without progression. One of the rarer glycogenoses; other neuromuscular variants existMuscle GlycogenosesGlycogen storage disoredre type V/McArdleMuscle glycogen phosphorylase (Myophosphorylase)Exercise intolerance; Disorders with muscle-energy impairment , male predominance.| glycogen in muscle, but cannot break it down, leading to painful muscle cramps, myoglobinuria (red urine) with strenuous exercise, and arrhythmia from electrolyte abnormalities. Autosomal recessive. McArdle = Muscle.Vll/TaruiPhosphofructokinase-M subunitAs for type V, with additional findings of a compensated hemolysis. Prevalent in Ashkenazi Jews and Japanese.Phosphoglycerate kinase deficiencyPhosphoglycerate kinaseAs for type V, with additional findings of a hemolytic anemia and CNS dysfunction. Rare, X-linkedPhosphoglycerate mutase deficiencyPhosphoglycerate mutase-M subunitAs for type V. Rare; most patients are African AmericanLactate dehydrogenase deficiencyLactic acid dehydrogenase-M subunitAs for type V, with additional findings of erythematous skin eruption and uterine stiffness resulting in childbirth difficulty in femaleFructose 1, 6-bisphosphate aldolase A deficiencyFructose 1, 6-bisphosphate aldolase AAs for type V, with additional finding of hemolytic anemiaPyruvate kinase deficiencyPyruvate kinase-muscle isozymeMuscle cramps and/or fixed muscle weaknessMuscle phosphorylase kinase deficiencyMuscle-specific phosphorylase kinaseAs for type V, some patients may have. Rare, autosomal recessive muscle weakness and atrophyb-enolase deficiencyMuscle b-enolaseExercise intoleranceDisorders with progressive skeletal myopathy and/or cardiomyopathyII/PompeLysosomal acid alpha1, 4-glucosidase (acid maltase)Infantile: hypotonia, muscle weakness, cardiac enlargement and failure, fatal early; Juvenile and adult: progressive skeletal muscle weakness and atrophy, proximal muscle and respiratory muscle are seriously affected. Autosomal Recessive. Heart, liver as well as muscle affected.Cardiac phosphorylase kinase deficiencyCardiac-specific phosphorylase kinaseSevere cardiomyopathy and early heart failure. Very rare diseaseGalactosemia with uridyl transferase deficiencyGalactose 1-phosphate uridyl transferaseVomiting, hepatomegaly, jaundice, cataracts, amino aciduria, failure to thrive. Long-term complications exist despite early diagnosis and treatmentGalactokinase deficiencyGalactokinaseCataractsUridine diphosphate galactose 4-epimerase deficiencyUridine diphosphate galactose 4-epimeraseSimilar to transferase deficiency with additional findings of hypotonia and nerve deafnessEssential fructosuriaFructokinaseAsymptomatic, positive urine reducing substance. BenignHereditary fructose intoleranceFructose 1-6 bisphosphate aldolase BVomiting, lethargy, failure to thrive, hepatic failure. Prognosis good with early diagnosis and fructose restrictionFructose 1, 6-diphosphatase deficiencyFructose 1, 6-diphosphataseEpisodic hypoglycemia and lactic acidosis