What Your Test Results Mean:

Female carriers are usually not affected with Duchenne or Becker muscular dystrophies because they make enough of the dystrophin protein. However, they can have some symptoms of Duchenne, such as changes to heart function, mild muscle weakness, fatigue, or cramping in their muscles. Female carriers have an increased chance to have a child with a DMD-related dystrophinopathy. Consultation with a genetic counselor for a more detailed risk assessment is recommended.

We recommend that you share this information with all of your health care providers. Since this is an inherited gene change, this information may be helpful to share with family members as it may impact their family planning and their own personal clinical management.

Disease Explained:

Duchenne muscular dystrophy (DMD) is typically diagnosed in early childhood, with first symptoms being identified as general motor delays, gait problems, delays in walking, and learning difficulties. Due to the progressive nature of DMD, children with DMD are usually wheelchair dependent by 12 years of age. Nearly all individuals with DMD are diagnosed with cardiomyopathy by age 18. Cognitive impairment characterized by low IQ and difficulty with short term verbal memory is also common. Most individuals with this condition do not survive past the age of 30.

Becker muscular dystrophy (BMD) is characterized by mild and later-onset symptoms in comparison to DMD. Symptoms of muscle weakness typically occur much later than in DMD; some individuals with BMD may not experience mobility issues until their late twenties. While muscle weakness is milder in individuals with BMD in comparison to DMD, cardiomyopathy is still a concern. Heart failure is the most common cause of death in individuals with BMD. Most individuals with this condition survive to their mid-forties.

Prognosis

The prognosis for Duchenne muscular dystrophy is variable, but most males will be wheelchair-dependent by age 13 and die before 30 years of age due to heart or respiratory failure. Males who have Becker muscular dystrophy have a longer life expectancy reaching into their forties or fifties. Prognosis in females is generally better, but lifespan may still be shortened in the presence of dilated cardiomyopathy.

Treatment

Management of the disease is generally focused on a combination of physical therapy, medication, and regular cardiac and respiratory screenings. Female carriers should be treated by a cardiologist.