In large bowl, combine flours, baking powder, baking soda, pumpkin pie spice and salt. In a separate bowl, whisk together pumpkin, egg yolks, yogurt, orange juice and oil. In third bowl, beat egg whites until soft peaks form.
Mix wet ingredients into dry, just until blended. Fold in egg whites.
Coat heavy, large non-stick skillet with cooking spray. Using one-fourth cup measure, dollop batter into pan, spreading with rubber spatula to make 4-inch pancakes. When small bubbles appear, about 3 minutes, turn pancakes and brown on other side. Transfer to plate and repeat, making 12 pancakes. Serve immediately, accompanied by maple syrup, if desired.