# How are tag variants identified in Open Targets Genetics?

**URL:** <https://community.opentargets.org/t/how-are-tag-variants-identified-in-open-targets-genetics/258>\
**Category:** Open Targets Genetics FAQs\
**Created:** [12 July 2021 09:24 UTC](https://community.opentargets.org/t/how-are-tag-variants-identified-in-open-targets-genetics/258 "2021-07-12T09:24:47Z")\
**Posts on this page:** 1\
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**Author:** ![JeremyS](https://dub1.discourse-cdn.com/flex017/user_avatar/community.opentargets.org/jeremys/32/76_2.png) [@JeremyS](https://community.opentargets.org/u/JeremyS)\
**Post date:** [12 July 2021 09:24 UTC](https://community.opentargets.org/t/how-are-tag-variants-identified-in-open-targets-genetics/258/1 "2021-07-12T09:24:47Z")

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In Open Targets Genetics, two methods are used to expand lead disease-associated variants into a more complete set of possibly causal tag variants, depending on whether or not a study has summary statistics:

- For studies in Europeans with summary statistics, we use credible set variants as the tag variants.

- For studies without sumstats or which aren’t primarily European, we compute the linkage disequilibrium (LD) as a weighted average (based on the number of individuals) of LD correlations from the 1000 genomes super-populations most likely matching the reported study ancestries.

Check out the [OT Genetics documentation](https://genetics-docs.opentargets.org/our-approach/assigning-traits-to-loci#lead-variant-to-tag-variant-expansion) for more information.