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Old 03-13-2011
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Biochemistry Why the child should eat more frequently?

A 4 yr-old boy is brought to the pediatrician because of gastroenteritis for three days, followed by a brief generalized seizure that left him semicomatose. The blood glucose level at admission is 18 mg/dL and urine is negative for glucose and ketones, but positive for a variety of organic dicarboxylic acids. IV administration of glucose improves his condition within 10 mins. Following diagnosis of an enzyme deficiency, his parents are cautioned to make sure he eats frequently. Which of the following is the most likely diagnosis?

A) Glucose-6-phosphatase deficiency
B) Hepatic glycogen phosphorylase deficiency
C) Medium chain acyl CoA dehydrogenase deficiency
D)Mitochondrial carbamoyl phosphate synthetase deficiency
E) Ornithine transcarbamoylase deficiency

I'll type the answer and I also have a question afterwards... Thanx.
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Old 03-13-2011
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C is the answer in my opinion
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Old 03-13-2011
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Default C. Mcad

I agree with Bronchiole - MCAD
  • hypoglycemic/hypoketotic + hyperammonemia --> comatose state
  • the organic dicarboxylic acids in the urine are products of incomplete ω-oxidation (an attempt to make up for the lack of β-oxidation)
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Old 03-14-2011
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Default C.

Yes, the correct answer is C.... But what if another option would have been F) Carnitine deficiency?

My question now is.. how would you differentiate between a Carnitine deficiency and an Acyl-CoA dehydrogenase deficiency? since.......

Kaplan:
Hypoglycemia with hypoketosis after fasting suggests a block in a fatty acid oxidation. Accumulation of organic dicarboxylic acids further indicates a fatty acyl-CoA dehydrogenase deficiency; most commonly this will be a medium chain acyl CoA dehydrogenase deficiency.This blockage may also lead to a secondary carnitine deficiency.

FA 2010 p.112: Carnitine deficiency leads to HYPOKETOTIC HYPOGLYCEMIA + hypotonia + etc...

Acyl-CoA dehydrogenase deficency leads to increased dicarboxylic acids, decreased glucose and ketones.

thanks..
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