Learn The BasicsDuchene muscular dystrophy (DMD) is a rare genetic disease characterized by progressive muscle weakness and wasting.
Here are the answer to some of the most frequently asked questions about DMD:
Who can be diagnosed with DMD?
DMD is an X-linked recessive disease, meaning that it mostly affects males. Because females have two X chromosomes, even if they carry one faulty X chromosome, the other one is able to compensate. Males, on the other hand, only have one X chromosome and develop DMD if this chromosome is faulty.
What causes DMD?
DMD is caused by a mutation in the DMD gene. This gene codes for a protein called dystrophin, which is essential for the health of muscle cells. The mutation leads to no functional dystrophin protein being made and muscle cells become damaged and waste away with time.
If I have a son with DMD, will his brother also have the disease?
No. DMD is inherited in an X-linked recessive manner. This means that a carrier mother has a 50% chance of passing the X chromosome carrying the faulty gene onto her children.
If the child is a boy, meaning he inherited a Y chromosome from his father, he has a 50% chance of developing DMD and a 50% chance of being healthy.
If the child is a girl, she has a 50% chance of also being a carrier like her mother and a 50% chance of being healthy.
What are the early signs of DMD?
The early signs and symptoms of DMD include enlarged calf muscles, toe walking, frequent falls, difficulty getting up from the floor, difficulty running, jumping and climbing stairs, a waddling gait, muscle pain and stiffness, delayed growth and learning difficulties.
How do doctors know it is DMD?
Your doctor may diagnose DMD based on a medical history and physical exam, blood tests, electromyography (a test that measures the electrical activity of the muscles in response to an electrical stimulus) or a muscle biopsy.
A definitive diagnosis can be reached based on a genetic test that reveals the presence of a mutation in the DMD gene.
Could my child maintain the ability to walk?
No. All patients affected by DMD eventually lose the ability to walk, usually by the time they are age 12.
How common is DMD?
DMD affects around one in 3,500 male births worldwide.
Are there any treatments?
The first-line treatment for DMD is corticosteroids.
There are also a number of disease-modifying therapies, including ataluren (Translarna), which is not yet approved in the U.S., eteplirsen (Exondys 51), golodirsen (Vyondys 53), casimersen (Amondys) and viltolarsen (Viltepso) and delandistrogene moxeparvovec-rokl (Elevidys).
Who will treat my child with DMD?
A multidisciplinary care team may include a neuromuscular specialist, cardiologist, endocrinologist, gastroenterologist, nutritionist, orthopedist, physiotherapist or pulmonologist, among others.
What is the prognosis like?
The outlook of DMD is generally poor with patients developing a waddling gait and typically losing the ability to walk by the time they are age 12.
As the disease progresses, weakness in the muscles of the throat can lead to episodes of aspiration, regurgitation of liquids from the nose, and the voice becoming “nasal” a nasal quality of voice.
Patients’ overall median life expectancy is 22 years, with respiratory and heart complications being the main cause of death.
Are there any support groups?
There are many organizations that can offer support for families affected by DMD. These include the Muscular Dystrophy Association, Parent Project Muscular Dystrophy, Muscular Dystrophy UK and CureDuchenne, to name a few.