What are "anti d's"? The BHMT variations tested by Yasko are meaningless, so it's unlikely they are causing anything. Some relevant ones are at http://forums.phoenixrising.me/index.php?threads/interesting-bhmt-and-bhmt2-variations.24512/ A gene can have hundreds or thousands of SNPs. 23andMe usually test for somewhere between a few and dozens per gene, though sometimes they test none and sometimes they test hundreds per gene. Each SNP can have an impact independent of other SNPs on that gene. Sometimes +/+ means absolutely nothing at all, such as for the BHMT SNPs tested by Yasko. It's a symbol used by whoever is interpreting your results, indicating that they think it's a risk. To see if it is a risk, and what it's a risk of, it's necessary to read the research. +/- is usually completely meaningless, or just has a very tiny impact. Some missense mutations are an exception, such as MTHFR C677T. In the case of COMT, research shows that V158M is only known to have an impact when homozygous (+/+), though it is a fairly substantial impact then. H62H also only has an impact when homozygous. So again, they're probably not having much of an impact, if any.