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Old 10-31-2015
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Default Fa oxidation diseases

Hey guys could someone explain this to me?? Its a question from Kaplan qbank

Kid with hypoglycemia/hypoketonemia has cardiomegaly/muscle aches/etc and dies at 5year old . Labs at an exam showed elevated carnitine esters in serum AND muscle tissue

The answers were some glycogen storage and 1)Carnitine Uptake Deficiency
2) LCAD Deficiency and I chose Carnitine since if Cat-1 makes the carnitine esters and there is no uptake of them in the mitochondrion they should accumulate... But it was LCAD deficiency and in the explanation they say ''Since Carnitine-esters are accumulating in serum and in muscle tissue , a carnitine uptake deficiency is ruled out'' !! Why is that??And also , shouldnt LCAD deficiency cause accumulation of simple FA's (not ''carnitized'' )

Thanks a lot
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Old 10-31-2015
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This has to be LCAD/MCAD deficiency.
Hypoglycemia along with Hypoketosis is a hallmark of this disease. Because otherwise in all pathologies if there's hypoglycemia, there would hyper-ketosis! Only except in this disease.
C8-C10 acyl carnitines (carnitine esters) accumulate in the blood because it cannot be further oxidized.
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Old 10-31-2015
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Also, the qs says the kid dies at the age of 5 right?
It's MCAD/LCAD that's so severe that leads to death early in life.
Whereas, Carnitine deficiency is milder and has a late-onset. Muscle aches etc in it are only provoked upon exercise.
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Old 10-31-2015
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By the way, when I say Carnitine deficiency I mean "Carnitine Acyltransferase Deficiency".
Are you sure the qs is talking about the same enzyme? Increased Carnitine esters in the blood would rule out deficiency of this enzyme, because if this enzyme is not present, they wouldn't be formed in the first place!
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Old 10-31-2015
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Correction: Hypoglycemia + Hypoketosis together is a hallmark of Fattt acid B-oxidation defect. In all other pathologies with hypoglycemia there would always be hyper-ketosis.
Sorry about the misconception.
But all the other points I mentioned above are right.
Someone correct me please if I am wrong?
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