I just ran across this tonight. It looks like this one significantly reduces folate absorption. Here is the reference:
http://www.psychweekly.com/aspx/article/articledetail.aspx?articleid=1581
“FOLH1 genotype strongly differentiated between patients who showed a good treatment response and those who did not,” says Dr. Roffman. “The FOLH1 variant also had a significant effect on baseline blood folate levels. Individuals with the low functioning FOLH1 variant (484C) had significantly lower baseline folate levels compared to those with the high functioning variant (484T). This may explain why patients with the low functioning variant failed to show a significant improvement in negative symptoms, as it took 8 weeks for their folate levels to catch up to those found in patients with the normal functioning version of the gene.”
http://www.psychweekly.com/aspx/article/articledetail.aspx?articleid=1581
“FOLH1 genotype strongly differentiated between patients who showed a good treatment response and those who did not,” says Dr. Roffman. “The FOLH1 variant also had a significant effect on baseline blood folate levels. Individuals with the low functioning FOLH1 variant (484C) had significantly lower baseline folate levels compared to those with the high functioning variant (484T). This may explain why patients with the low functioning variant failed to show a significant improvement in negative symptoms, as it took 8 weeks for their folate levels to catch up to those found in patients with the normal functioning version of the gene.”