[rosegarden1]

Maybe the questoin is simple but i couldn't find an answer in clinical textbooks. organic acidemias are related with amino acid catabolism and there's a block in catabolism pathway. so if the amino acids can't degrade to their end products such as pyruvate or acetyl coA, where the ketone bodies seen in these disorders come from?

[ATMyller]

Beta-oxidation of fatty acids produces acetyl-CoA as well.

[rosegarden1]

why does the beta oxidation of fatty acid increase then?

[Babcock_Hall]

Do you have a citation which indicates that the production of ketone bodies rises when there is a particular metabolic block?  I have to wonder whether or not we may be thinking of two different things.  in phenylketonuria, the concentrations of phenylpyruvate and related metabolites rise in the urine and blood, for example, and phenylpyruvate is an organic ketoacid.

[rosegarden1]

luckily i found the answer. thank you for your reply.
organic acids can inhibit gluconeogenesis therefore fatty acid oxidation increases to meet body's energy requirement. Also organic acidemias cause hyperammonemia by inhibiting urea cycle.

reference:https://books.google.com.tr/books?id=a7CqcE1ZrFkC&pg=RA3-PA987&dq=organic+acidemia+ketosis&hl=tr&sa=X&redir_esc=y#v=onepage&q=organic%20acidemia%20ketosis&f=false

[Babcock_Hall]

Your reference also notes that some organic acidemias are associated with hypoketotic hyperglycemia.  I am not surprised that difference metabolic defects show a variety of outputs.

[rosegarden1]

yep,that's related with which organic acid is accumulated.