The epicanthic fold also popped up in my Ukrainian lineages but that is key...it pops up, it doesn't affect an entire family. My belief based on the history of the greater Lithuania/Poland region is that it is a residual genetic impact (what a nice way to describe what often was "rape", eh?) from the Tatar invasions of the areas within that region in the 12th-17th centuries.
aka Debra Katz
Pacific Beach CA USA