5 posts
MTHFR variants are common, their effect on depression risk is small, and the clinically useful signal sits in downstream biochemistry rather than the genotype. How to find your own genotype in a VCF and what to measure instead.
Two different tests share the name methylation testing: genotyping of one-carbon metabolism genes like MTHFR, and direct measurement of DNA methylation across the genome. This explains what each one measures, how to extract the data yourself, and where the interpretation stops.
There are two products sold as a 'methylation report': an MTHFR-style SNP panel from genotyping data, and a genome-wide DNA methylation array read out as epigenetic clocks. They measure different things, and only one of them is a measurement of your current biology.
Genetic Genie's methylation panel reads about two dozen genotypes out of a consumer array file. This guide shows how to extract and verify those calls yourself, what they can and cannot tell you, and how to measure actual DNA methylation if that is what you were after.
A step-by-step method for pulling rs1801133 and rs1801131 out of a 23andMe, AncestryDNA, or WGS file yourself, getting the strand right, and understanding what the result does and does not tell you.