Fatty Acid degradation
-Occurs in mitochondria or peroxisomes
First step - uptake of the fatty acids by the cell and addition of CoA to them
Second step - Uptake of the Fatty Acyl CoA molecule into the mitochondria by the Carnitine Shuttle *( which involves removal and then addition of the CoA molecule again to the fatty acid once inside the mitochondria)
Once in the mitochondria the fatty acid may undergo , Beta-oxidation ( a process in which a fatty acid is oxidized/cleaved at the Beta carbon to generate Acetyl CoA in several cycles )
An Acyl CoA dehydrogenase catalyzes the initial step
.
Look out for Hypoketotic Hypoglycemia in defects of fatty acid degradation
The 2 main subtypes to be aware of are
-a problem with the carnitine shuttle ( systemic carnitine deficiency)
- or with an Acyl CoA dehydrogenase ( eg MCAD deficiency )
notyasupremeIt's actually funny because the question stem makes it seem like it's an MCAD deficiency (presence of dicarboxylic acid) and all the symptoms, but then treat it with MCAD. Whatever, I got it right but it just felt like a weird question to me. +4
nbmeanswersownersucksyeah I was confused too but I also think the negative serum carnitine is supposed to help r/o MCAD deficiency since that usually has elevated serum carnitine. +1
baja_blastIf Carnitine was an option here, how could we differentiate this from primary carnitine deficiency? Would it have been possible?+11
melanomathe presence of dicarboxylic aciduria is more related to mcad/lcad deficiency. the patient receives medium chain tryglicerides because he has the enzyme to metabolize it.+10
topgunberjust a few things, sure it sounds like mcad but lcad would present similarly, except in MCAD, giving medium chain triglycerides would worsen symptoms as compared with LCAD. + Similarly when fatty acids cant undergo Beta oxidation they undergo omega oxidation- which is why there is increased dicarboxlic acids (i.e. dont just jump for MCAD when you see dicarboxilic acids). Last of all it would be difficult to differentiate but if the patient were deficient in carnitine the treatment with MCADs would not show improvement because carnitine is required to shuttle the fatty acid into the MTs. +2
topgunber'a 'weird question' because my school never asked it' +1
sexymexican888According to UWORLD: Primary carnitine deficiency elevated muscle triglycerides. MCAD, will not+2
submitted by โandro(269)
Fatty Acid degradation
-Occurs in mitochondria or peroxisomes
First step - uptake of the fatty acids by the cell and addition of CoA to them
Second step - Uptake of the Fatty Acyl CoA molecule into the mitochondria by the Carnitine Shuttle *( which involves removal and then addition of the CoA molecule again to the fatty acid once inside the mitochondria)
Once in the mitochondria the fatty acid may undergo , Beta-oxidation ( a process in which a fatty acid is oxidized/cleaved at the Beta carbon to generate Acetyl CoA in several cycles )
An Acyl CoA dehydrogenase catalyzes the initial step .
Look out for Hypoketotic Hypoglycemia in defects of fatty acid degradation
The 2 main subtypes to be aware of are -a problem with the carnitine shuttle ( systemic carnitine deficiency) - or with an Acyl CoA dehydrogenase ( eg MCAD deficiency )