homocystein, methionine levels

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Match the cause with the lab values
a)vitamin B12 deficiency Lab___________
b)cystathionine β-synthase Lab___________
c)cystathionase deficiency Lab___________
d) folate deficiency Lab___________

lab1: High serum homocystein, high methionine, low cystine, normal methylmalonic acid
lab2: High serum homocystein, low methionine, high cystine, normal methylmalonic acid
lab3: High serum homocystein, low methionine, low cystine, normal methylmalonic acid
lab4: High serum homocystein, high methionine, low cystine, high methylmalonic acid
lab5: High serum homocystein, low methionine, high cystine, high methylmalonic acid

 

[PowerDan]

Based on my reasoning it should be.

a) Vit B12 deficiency - Lab 5.

b) Cystathionine β-synthase deficiency - Lab 1

c) Cystathionine lyase deficiency - Lab 1

d) Folate deficiency - Lab 2

 

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Based on my reasoning it should be.

a) Vit B12 deficiency - Lab 5.

b) Cystathionine β-synthase deficiency - Lab 1

c) Cystathionine lyase deficiency - Lab 1

d) Folate deficiency - Lab 2

Correct.
How about Vit B6 deficiency?

 

[FindMeOnTheLinks]

You know what's messed up? I went through first year, and my school never had a lecture detailing any of this. So now I'm going to be left to learn it completely on my own at some point before step 1. Just really ticks me off. Thanks for reading my rant.


Sent from my iPhone using SDN mobile

 

[PowerDan]

Correct.
How about Vit B6 deficiency?

Same as Cystathionine β-synthase deficiency, I expect - because Vitamin B6 is a co-factor in that reaction.

 

[enhancers]

Same as Cystathionine β-synthase deficiency, I expect - because Vitamin B6 is a co-factor in that reaction.

Right.
10 years old pt with chest pain, lab shows high methionine level. Which aminoacid is essential particularly in this pt?

 

[Reperfused]

Right.
10 years old pt with chest pain, lab shows high methionine level. Which aminoacid is essential particularly in this pt?

Cysteine?

 

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Cysteine?

Yes!
Look this diagram to ans all the Questions.

 

[Reperfused]

Yes!
Look this diagram to ans all the Questions.
View attachment 207064

Thanks for sharing!
Please ask more questions if you have them. This is interesting. I integrated your initial question with the FA diagram and it all started making perfect sense! 🙂

 

[Pushtothestars]

Based on my reasoning it should be.

a) Vit B12 deficiency - Lab 5.

b) Cystathionine β-synthase deficiency - Lab 1

c) Cystathionine lyase deficiency - Lab 1

d) Folate deficiency - Lab 2

Can someone explain how def in folate causing increase in homocysteine low met high cysteine and normal mma? Please

 

[PowerDan]

Can someone explain how def in folate causing increase in homocysteine low met high cysteine and normal mma? Please

N5-Methyl-Tetrahydrofolate acts as a methyl donor in the conversion of of Homocysteine to Methionine. [catalyzed by Homocysteine methyl transferase - also called Methionine synthase]

Deficiency of Folic acid would thus result in low levels of Methionine and increased accumulation of Homocysteine. These high levels of Homocysteine would in turn get shunted into the alternative Cystathionine beta synthase pathway - causing more production of cysteine.

Methyl-malonate levels will remain normal because that has nothing to do with folate really. Methyl-malonate levels are elevated only in Cobalamin deficiency (or a rare enzyme deficiency of methyl-malonyl CoA mutase).

 

[Pushtothestars]

N5-Methyl-Tetrahydrofolate acts as a methyl donor in the conversion of of Homocysteine to Methionine. [catalyzed by Homocysteine methyl transferase - also called Methionine synthase]

Deficiency of Folic acid would thus result in low levels of Methionine and increased accumulation of Homocysteine. These high levels of Homocysteine would in turn get shunted into the alternative Cystathionine beta synthase pathway - causing more production of cysteine.

Methyl-malonate levels will remain normal because that has nothing to do with folate really. Methyl-malonate levels are elevated only in Cobalamin deficiency (or a rare enzyme deficiency of methyl-malonyl CoA mutase).

Thanks that cleared it up for me 🙂