152. A child with hypoglycemia is not able to utilize glucose from glycogenolysis or gluconeogenesis. Which of the following enzyme is deficient in the child?
Ans. c. Glucose 6-phosphatase Von Gierk's disease (AR) Inherited as autosomal recessivedeg Caused by glucose-6-phosphatase deficiency in liver, kidney, and intestinal mucosa. Skeletal muscle is deficient in glucose-6 phosphatase, so muscles are not affecteddeg. Structure of glycogen is normaldeg but not available metabolically Two subtypes of GSD I Type la Type lb Defective enzyme:Glucose-6- phosphatase Defective enzyme: Translocase The defects in both subtypes lead to inadequate conversion in the liver of glucose-6-phosphate to glucose and thus make affected individuals susceptible to fasting hypoglycemia Von Gierk's disease (AR) Clinical Features Clinical features are hypoglycemia, lactic academia, ketosis, hyperlipidemia, increased uric acid and splenomegalyQ Liver cells and renal tubule cells loaded with glycogendeg. Organs affected are liver, intestine and kidneydeg Long-Term Complications Gout, polycystic ovaries, hepatic adenomas Increased risk of pancreatitis, cardiovascular disease. Frequent fractures (osteopenia/osteoporosis) Renal disease (proteinuria, hypeension, kidney stones, nephrocalcinosis, and altered creatinine clearance) Pulmonary hypeension (rare) Diagnosis: Clinical presentation and abnormal plasma lactate and lipid values suggest that a patient may have GSD I Gene-based mutation analysis provides a noninvasive means of reaching a definitive diagnosis for most patients of GSD I Definitive diagnosis required a liver biopsy to demonstrate a deficiency. Treatment of Type I GSD: Maintenance of normal blood glucose levels through continuous infusion of glucose feeding tube or ora administration of uncooked cornstarch (slow-release form of glucose) Fructose and galactose cannot be conveed to free glucose, their dietin take should be restricted Dietary supplements of multivitamins, calcium and Vitamin D Allopurinol Use of medium chain triglycerides, fish oil and lipid-lowering drugs such as statins and fibric acids ACE inhibitors, Citrate supplementation Ohotropic liver transplantation: Reserved for GSD I patients with liver malignancy, multiple liver adenomas, metabolic derangements refractory to medical management, and/or liver failure.
Fructokinase
Glucokinase
Glucose 6-phosphatase
Transketolase