This is what I found Corn syrup like karo doesn’t crystallize very much compared to regular cane sugar. So it’s often used when making caramel, candies, or other recipes where you need to heat up sugar but don’t want it to crystallize and harden. Since it is used to make the icing pliable (less hard), I don’t think it would work. You could try. But I think it will work fine without the corn syrup. Try a small batch and see if it rolls ok for you. If it is hard to roll, add some homemade or maybe a bit of honey.