The science of transgender is still in its infancy, but evidence so far points to it being biological. Differences in brain have been seen, and I’ve covered them before here on OMH. However, genetic evidence is also being published! This week, let’s take a look at CYP17. CYP17 is a gene that makes enzymes that are part of sex hormone synthesis. Mutations in CYP17 have been noted in some intersex conditions, such as adrenal hyperplasia.
Now, there’s a SNP that’s been noticed in CYP17. SNPs are “single nucleotide polymorphisms”, which takes some explaining. SNPs are very, very tiny mutations in genes — just one letter in the DNA alphabet changes! SNPs don’t usually change the protein that the gene makes very much.
So we have this gene — CYP17, that is involved in making sex hormones. And we have this tiny mutation, this SNP. Now let’s look at the science!
Specifically, let’s look at this one study that was published back in 2008. They looked at the CYP17 gene in 102 trans women, 49 trans men, 756 cis men, and 915 cis women. They compared the CYP17 of trans women to cis men, and trans men to cis women. Unlike many studies, this comparison makes sense. We’re talking about the DNA in the genes here, not something that’s changed by hormonal status.
They found multiple things:
- There was no difference between trans women and cis men
- Trans men were more likely to have a SNP in their CYP17 than cis women were.
- Cis men, trans women, and trans men all had the SNP more frequently than cis women
What does that mean?
We don’t know yet. But it does appear that CYP17 is a gene that it might be worth looking deeper into to find potential causes for transgender.
Want to read the study for yourself? The abstract is publicly available.