DILLON, living with Duchenne.

Diagnosing Duchenne

Diagnosis: One Family's Journey

JB describes how her own intuition and concern for her son Charlie's development led eventually to a diagnosis of Duchenne muscular dystrophy.


Confirming a Duchenne Diagnosis

Although muscle damage starts at birth, the signs of Duchenne are typically first noticed in children at around 2.5 years of age. Duchenne is diagnosed at an average age of 5 years, a delay of 2.5 years after symptoms are usually first noticed. Confirming a Duchenne diagnosis earlier will help patients access and understand treatment options, potentially delaying disease progression. An earlier diagnosis will also enable family members to receive genetic counseling and take advantage of support networks. 

Working with your child’s doctor, the first test will likely be a creatine kinase (CK) test, which involves a simple blood draw. CK is an enzyme in muscle cells that is released into the blood during muscle injury.

Trust your gut. Caregivers play an important role in diagnosing Duchenne–80% of the time when they express concerns about developmental problems, they are correct. 

Having productive conversations with your child's or loved one's physician is very important, but may also be challenging. Our Doctor Discussion Guide can help you get more from these important interactions.

What Constitutes a High Creatine Kinase (CK) Level?

Although the normal range of CK levels varies with age and gender, CK levels in Duchenne are typically elevated 50- to 200-fold above normal levels, as shown in the table below.

If CK levels are high, your child’s doctor may refer you to a specialist for genetic testing. The genetic test helps to determine if your child has a genetic mutation associated with Duchenne to confirm the diagnosis.

Genetic Testing

Genetic testing is a laboratory procedure that looks closely at a sample of a person's DNA to assess whether they have genetic variants (changes in the gene) that are associated with a disease. Typically, it involves a blood or saliva sample.

In Duchenne, genetic testing can:

  • Confirm a diagnosis
  • Identify the genetic variants associated with Duchenne so that care options can be considered
  • Provide information for identifying appropriate clinical trials for potential participation
  • Identify Duchenne carriers so that appropriate monitoring can be initiated
  • Identify other family members who may benefit from genetic testing, for example, siblings and other relatives


When Genetic Testing Is Inconclusive

In rare cases, genetic testing may be inconclusive. In these situations, the specialist may recommend a muscle biopsy to determine whether dystrophin is present or absent. Only a doctor can accurately diagnose a child with Duchenne. If your family’s pediatrician becomes concerned that your child needs further testing, the first step may be a referral to a specialist—typically a pediatric neurologist or neuromuscular expert. These specialists will work to identify the cause of your child’s symptoms and may recommend additional testing.

Speak with your child’s doctor about genetic testing to find out which genetic test is right for you and your family.

There are several no-cost genetic testing programs:

Decode Duchenne: provides no-cost genetic testing, interpretation, and counseling through PPMD and PerkinElmer.

Detect MD: provides no-cost genetic testing, interpretation, and counseling through Invitae.


Common steps many families experience include:

Observing signs and symptoms


Blood tests to determine enzyme levels (creatine kinase, or CK, test)


Referral to a specialist


Genetic testing


Muscle biopsy (if needed)

If you know or suspect that your child has developmental delays, talk with your child's doctor about a CK test. Our Guide to Genetic Testing may help you find the information you need.

Stay Connected

Sign up to receive the latest information and community resources and we'll send you a Sarepta Caregiver Journal at no charge.