Inborn Errors 1 & 2: Hypoglycemia and Disorders of Fat Utilization Flashcards
How can you differentiate defects in gluconeogenesis and fatty acid breakdown?
Both present with hypoglycemia upon fasting, but defects in gluconeogenesis will present with ketones while defects in fatty acid breakdown will not.
What is the “Whipple’s triad” definition of hypoglycemia?
Autonomic activation: sweating, shaking, tachycardia, anxiety, weakness, hunger
Neuroglycopenic symptoms: irritable, resltess, headache, confusion, visual changes, slurred speech, behavior changes, somnolense, coma
BG less than 50 mg/dL Resolution with ingestion of glucose
Where does blood glucose come from fasting by hour?
0 - 4 hours after eating: absorption
4 - 14 hours after eating: glycogenolysis
10 - 18 hours after eating: gluconeogenesis
12 - … hours after eating: fatty acid oxidation
When glucose can’t get out of the liver, what other pathway can it take?
It can be converted to triglycerides (which show up as high serum triglycerides).
Von Gierke disease typically presents _______ hours into fasting.
4-6
Two other chemical products are produced in those with glucose 6-phosphatase deficiency: _____________.
uric acid (because the ribose monophosphate shunt creates purines) and lactic acid (because of the backing up of gluconeogenesis)
Von Gierke is a glycogen synthesis disorder type ____.
1
Those with glucose 6-phosphatase deficiency require what treatments?
Constant glucose (to avoid any gluconeogenesis)
Drip feeding
Cornstarch (which is slow release carbohydrate)
What is the classic presentation of glycogen storage defect (GSD 0)?
Hyperglycemia after a meal followed by hypoglycemia, lactic acidosis, and ketotic acidosis
No liver enlargement.
____________ leads to cirrhosis that typically requires liver transplant by age 4-6.
Branching enzyme defect (GSD IV)
Hereditary fructose intolerance results from _______________.
defects in aldolase B which is responsible for splitting fructose into two 3-carbon units
The mitochondrial form of HMG co-a synthase participates in __________- while the cytosolic form participates in ____________.
ketone formation; cholesterol synthesis
Increased serum acylcarnitines, abnormal urinary organic acids, and increased serum acyl co-a are indicative of ___________.
MCAD deficiency (medium-chain acyl co-a dehydrogenase deficiency)
What is one cause of congenital hyperinsulinemia?
If a woman has hyperglycemia while pregnant, then the baby will make more insulin. When the baby leaves the mother’s uterus, the glucose is gone but the insulin remains high –leading to hypoglycemia after birth.
What are two causes of congenital hyperinsulinemia?
If a woman has hyperglycemia while pregnant, then the baby will make more insulin (because maternal insulin does not cross the placenta). When the baby leaves the mother’s uterus, the glucose is gone but the insulin remains high –leading to hypoglycemia after birth.
Another cause is a defect in the potassium channels that regulate insulin secretion. If they are congenitally blocked, then insulin will be secreted continuously.
