Because muscular dystrophy weakens muscles over time, teens who have the disease can lose the ability to do stuff that we take for granted, like walking or sitting up. MD is caused by a problem in a person's genes. Pretend you're a cook with a recipe for making brownies. The genes passed on from parents are like the recipe for muscles, and teens with MD have incorrect or missing information when it comes to making the proteins necessary for healthy muscles. Teens who have muscular dystrophy may have begun having muscle problems as infants, or they may have developed problems later on.
Some people even develop MD when they are adults.
But because MD is inherited, it isn't contagious and you can't catch MD from another teen. For specific medical advice, diagnoses, and treatment, consult your doctor.