that is because of the yellow, grey and black color they expeirience. A true leusistic is an animal with blue eyes and a completely white body, blizzards can be white, but its more common for one to be grey, a lot hatch out to have a hint of yellow, and some hatch out to have a completely yellow body.
As for your patternless, it is common for blizzards and just leopard geckos in general to have those kind of spots on their body, I havn't seen to many on a patternless but I imagine its just as common with blizzards. I believe they are just a sort of birthmark and I heard through the grape vine that its not inheritable, just luck of the draw. I wouldn't say you have anything too unusual, but if she keeps getting black on her foot like that then you may have something.
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Bradley Baquial