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sumeetmultani
Forum Elite Topics: 47 Posts: 340 |
a patient having mouth ulcer and eruption,cracking at mouth corner and ataxia..which of the following will be seen ... 1) inc. succinyl coa 2)inc. cystathione 3)dec methymalonyl coa answer with explanation only(plz) this ques came in exam as told by my friend..he doesnt know 4th choice but was saying it was irrelevant..
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khanz
| Forum Elite  Topics: 5 Posts: 292
I think ans is no.1 inc succinylcoa b/c its a B6 def which is involved in heme synthesis.
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sumeetmultani
| Forum Elite Topics: 47 Posts: 340
i too think of this ...no other choice is relevant with symptoms of patient. its either B2 deficincy OR B6 defi. and in anyways only succinyl coa has relation with them . cystathione should decrease and methymalonyl coa dec only if biotin is defficient..
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kaphoury
| Forum Newbie  Topics: 2 Posts: 41
I think this is due to vitamin B1 (thiamine) deficiency. this vit is essential for dehydrogenases like Succ. CoA Dehydrogenase involved in TCA cycle. B6 def may be more related to AST,ALT and ALA synthase . so i will go to Succ CoA
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kaphoury
| Forum Newbie Topics: 2 Posts: 41
kaphoury wrote: I think this is due to vitamin B1 (thiamine) deficiency. this vit is essential for dehydrogenases like Succ. CoA Dehydrogenase involved in TCA cycle. Ataxia may develop in B1 def as a consequence of Wernickes-Korsakoff..  B6 def may be more related to AST,ALT and ALA synthase . so i will go to Succ CoA
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eriebob
| Forum Newbie Topics: 1 Posts: 19
Deficiency is definitely riboflavin. Cheilitis (cracking and fissures) is a giveaway. Ataxia is consistent also. PDH, TCA and beta oxidation would be impaired. Not sure I like any of the answers. One might argue that since FAD is diminished that succinic DH deficiency would cause succinyl CoA to increase, but since acetyl CoA production is decreased and alpha-KGA DH is impaired I wouldn't really expect to see succinyl CoA increase. Are you sure those were the answers?
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sumeetmultani
| Forum Elite Topics: 47 Posts: 340
yeah..these were the choices...
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doc_vic
| Forum Newbie Topics: 55 Posts: 212
i agree this is riboflavin deficiency however none of the answers looks the best choice. I would pick 1) inc. succinyl coa
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spinal shock
| Forum Newbie  Topics: 23 Posts: 241
IF that's what had been shown in the exam i will review biochemistry one more time, are you sure that's the entire Q?
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eriebob
| Forum Newbie Topics: 1 Posts: 19
answer is decreased methylmalonate. I forgot about the MTIV amino acids that channel into succinyl CoA through methylmalonate. I am pretty sure that isoleucine and valine are oxidatively decarboxylated requiring riboflavin. Wow that was a tough question.
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arpita1586
| Forum Newbie Topics: 5 Posts: 90
blah! what just happened here!! 
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arpita1586
| Forum Newbie Topics: 5 Posts: 90
could you please explain in more detail.. i seem to be missing something here.
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StepPrep21
| Forum Junior Topics: 11 Posts: 110
its B2 (riboflavin) deficiency.....B2 is used to make FAD and FMN.....and in the citric acid cycle, FAD is used by succinate dehydrogenase.....which converts succinate into fumarate......no B12 leads decreased FAD which leads to decreased activity of succinate dehydrogenase which leads to an increase in succinate and its precursors (eg. succinyl CoA).......hope this helped clear the confusion.....to those that are studying....GOOD LUCK!!!
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StepPrep21
| Forum Junior Topics: 11 Posts: 110
and its definitely not B12 deficiency, because a B12 deficiency would cause INC methylmalonyl-Coa and DEC succinly CoA....so b12 is ruled out.....
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nitts2009
| Forum Guru Topics: 19 Posts: 565
Riboflavin will not cause ataxia The answer is Increase in cystathione (page 110, First Aid 2009) if b12 is deficient, homocysteine accumulates, hence forms cystathione.
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study499
| Forum Junior Topics: 16 Posts: 1940
nitts2009 wrote: Riboflavin will not cause ataxia The answer is Increase in cystathione (page 110, First Aid 2009) if b12 is deficient, homocysteine accumulates, hence forms cystathione. 
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stepdude1
| Forum Newbie Topics: 75 Posts: 381
agree with nitts
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