Note the huge difference in this ADMIXTURE bar graph from the recent Pankratov et al. paper between Lipka Tatars from Belarus and nearby Balts and Slavs. The Lipka Tatars are almost identical to Volga Tatars despite residing in their current homeland for about 500 years. I'm guessing the fact that they're Sunni Muslims might have something to do with it.
Pankratov, V. et al. East Eurasian ancestry in the middle of Europe: genetic footprints of Steppe nomads in the genomes of Belarusian Lipka Tatars. Sci. Rep. 6, 30197; doi: 10.1038/srep30197 (2016).