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Old 08-29-2011
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Biochemistry Why do we need folate to treat Homocystinurea

In FA book it is written that in cystathionine synthase deficiency the treatment will be decrease Met, increase Cys and increase B12 and folate in diet ,, why do i increase B12 and folate while cystathionine synthase need B6 not B12 ????
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I found this on wikipedia ,,,,

B12 is not used but Betaine is used.

Betaine (N,N,N-trimethylglycine) is used to reduce concentrations of homocysteine by promoting the conversion of homocysteine back to methionine. The re-formed methionine is then gradually removed by incorporation into body protein. The methionine that is not converted into protein is converted to S-adenosyl-methionine which goes on to form homocysteine again. Betaine is, therefore, only effective if the quantity of methionine to be removed is small. Hence treatment consists of a diet low in methionine and betaine. In classical homocystinuria (CBS) the plasma methionine usually increases above the normal range of 30 micromoles/L and the concentrations should be monitored as potentially toxic levels (more than 400 micromole/l) may be reached.
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Originally Posted by drnrpatel View Post
I found this on wikipedia ,,,,

B12 is not used but Betaine is used.

Betaine (N,N,N-trimethylglycine) is used to reduce concentrations of homocysteine by promoting the conversion of homocysteine back to methionine. The re-formed methionine is then gradually removed by incorporation into body protein. The methionine that is not converted into protein is converted to S-adenosyl-methionine which goes on to form homocysteine again. Betaine is, therefore, only effective if the quantity of methionine to be removed is small. Hence treatment consists of a diet low in methionine and betaine. In classical homocystinuria (CBS) the plasma methionine usually increases above the normal range of 30 micromoles/L and the concentrations should be monitored as potentially toxic levels (more than 400 micromole/l) may be reached.
thanks so much and if betaine is used for reformation of methionine as some will be incorporated into body protein as to decrease amount of homocysteine so by this way maybe FA is correct as by increasing B12 and folate i am enhaning N- methyl THF homocysteine transferase which convert homocystiene back to methionine .. am i right ?! .. thanks for ur help
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Originally Posted by menatallah Elgohary View Post
thanks so much and if betaine is used for reformation of methionine as some will be incorporated into body protein as to decrease amount of homocysteine so by this way maybe FA is correct as by increasing B12 and folate i am enhaning N- methyl THF homocysteine transferase which convert homocystiene back to methionine .. am i right ?! .. thanks for ur help
Yup, exactly,... Actually cystathione synthatse deficiency is there so we have to give cysteine. Now we have to get rid of homocyseine also because it will cause Osteoporosis, Atherosclerosis and Lens subluxation, so better to give B12 and convert it to methionine.
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Originally Posted by drnrpatel View Post
Yup, exactly,... Actually cystathione synthatse deficiency is there so we have to give cysteine. Now we have to get rid of homocyseine also because it will cause Osteoporosis, Atherosclerosis and Lens subluxation, so better to give B12 and convert it to methionine.
thanks soooo much
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