But both girls look amazing on the dance floor in this heart-wrenching performance to the song "Reflections" for the 2013 WHAS Crusade for Children telethon in Kentucky.
At first, both sisters sit in wheelchairs as they copy each other's movements through a faux mirror.
According to Wave 3 News, Gracie said the lyrics "who is that girl I see staring straight back at me? When will my reflection show who I am inside?" describe how she feels.
But then Quincy jumps out of the chair, able to dance freely for her sister.
According to the video's YouTube descriptions, the dance was choreographed by Jennifer Wood.
"It just tells the perfect story of Gracie's little heart and that she can do anything she wants to do," their mother Christin Latkovski told Wave 3 News.
It truly is a beautiful interpretation of what it means to overcome obstacles and share sisterly love.
Now, are you tearing up yet?