Ullrich congenital muscular dystrophy is a condition that mainly affects skeletal muscles, which are the muscles used for movement. Affected individuals show muscle weakness soon after birth. The muscle weakness is typically severe, and most affected people are not able to walk unassisted. Individuals with this condition develop joint stiffness (contractures) in their knees and elbows that can restrict movement. They also have an unusually large range of joint movement (hypermobility) in their wrists and ankles. The respiratory muscles may also be weakened, requiring people to use a machine to help them breathe at night (mechanical ventilation).