The main features of BMD are muscle weakness and muscle wasting (muscle loss). BMD is a progressive condition, with muscle weakness becoming more severe as a person grows older. Most individuals with BMD start to experience muscle weakness or cramping after exercise starting in late childhood or teenage years. Gradually, the muscles in the legs weaken and the symptoms become more noticeable. Some people with BMD, but not all, eventually require the use of a wheelchair. Most individuals with BMD are able to walk into their 20’s or later. Over time, the heart muscles and the breathing muscles can also become weaker. The most common cause of premature death for a man with BMD is related to the breakdown of the heart muscle. The average life expectancy is the mid 40’s, however some men with BMD have a normal lifespan. BMD does not affect intelligence.
What is life expectancy in BMD?
Most people with BMD survive well into mid- to late adulthood. For more about living with BMD, see Medical Management. If the cardiac aspects of the disease are minimal, or if they are adequately controlled through medical intervention, a normal or nearly normal life span can be expected.
The most serious issues with the muscular dystrophies involves the heart and breathing. The heart muscle and conduction system can be defective with serious consequence. Breathing system may be affected with risk aspiration and pneumonia. Some have mild learning problems. Many have orthopedic issues due to muscle imbalance and contractures and scoliosis. Vision and hearing may be affected.
Few individuals with dmd live beyond their 30s. Breathing complications and cardiomyopathy are common causes of death.