Hi, I’d be very interested if anyone has any insight into how the CTH S4031I gene variant affects the transsulfuration pathway, and if it changes the advice on dealing with CBS.
CTH appears to code for cystathionase (cystathionine gamma-lyase), which appears to sit below CBS – between cystathionine and cysteine+alpha-ketobutyrate. I don’t know if it comes before or after ammonia (I think I have seen it in either position, depending on source). I am picturing a bottleneck effect with CBS sped up and CTH slowed down (I assume CTH is slowed down as SNPedia has the +/+ genotype as causing “significantly higher plasma total homocysteine concentration” http://www.snpedia.com/index.php/Rs1021737).
I’ve done a forum search and not found any discussion of CTH impact.
My SNPs are CBS C699T +/+ , CTH S4031I +/+
Many thanks
Nick
CTH appears to code for cystathionase (cystathionine gamma-lyase), which appears to sit below CBS – between cystathionine and cysteine+alpha-ketobutyrate. I don’t know if it comes before or after ammonia (I think I have seen it in either position, depending on source). I am picturing a bottleneck effect with CBS sped up and CTH slowed down (I assume CTH is slowed down as SNPedia has the +/+ genotype as causing “significantly higher plasma total homocysteine concentration” http://www.snpedia.com/index.php/Rs1021737).
I’ve done a forum search and not found any discussion of CTH impact.
My SNPs are CBS C699T +/+ , CTH S4031I +/+
Many thanks
Nick