I've been fascinated by the CBS effect on ammonia debate and in my research it occurred to me that maybe there is a small defect on a urea cycle gene that works with the CBS gene causing problems. My hypothesis is that there is a slow down in the urea cycle converting ammonia to urine and that coupled with CBS increasing the amount of ammonia. Does this make sense, even if you disagree with Yasko? So I went through every 23andme OTC gene on SNPedia and came up with homozygous ancestral every time. I think that this makes sense because it seems like a person with a snp in a heavily researched urea cycle location would probably not make it to adulthood. So then I looked for heterozygous alleles especially in locations that had not been researched at all. So, for me I came up with three: Rs4621959 Wild:A 30% MAF (very common with no studies) Rs5963418 Wild:A 4% MAF (relatively rare with no studies) Rs5963419 Wild:T 36% MAF (increasingly common) So I am wondering if anyone else has either of these heterozygous alleles? Do you think you have a problem with ammonia? Did you feel anxious when you went on MeFolate or MeB12? They may have absolutely no effect on anything. It is just something that I am really interested in and wondering if anyone has any info.