My cousin has a muscle disorder. I don't know the exact name but I know that she was born with it.
When she was little, she could walk. She had an odd stride to her walk, but she was walking nonetheless. As she got older however, her muscles became weaker and weaker and her leg muscles could no longer carry her.
She can't walk now and has to be in a wheelchair. It's so disheartening to see her like that. I hope she can be cured one day.