Approximately 360 babies with Duchenne are born each year in the United States. Without newborn screening, the typical family will notice symptoms of Duchenne in their child by age 2, yet most of those families will not receive a diagnosis until age 5.  This delay is even longer in families of color and low socioeconomic status. Evidence of muscle damage is present in infancy. By age 5, children with Duchenne have significant and irreversible muscle damage.

There are now eight FDA-approved treatments for Duchenne, four of which are approved for use in infancy. Newborn screening can eliminate the delay in diagnosis and provide families the opportunity for treatment years earlier, when children have more functional muscle tissue remaining.

The first-tier screen for Duchenne evaluates CK-MM, the muscle isoform of creatine kinase. CK-MM is a biomarker of muscle damage and is highly elevated in newborns and children with Duchenne. In the event of elevated CK-MM, confirmatory testing—DNA sequencing of the dystrophin gene, DMD—is required. The presence of a pathogenic variant in DMD confirms the diagnosis. Both the screening and confirmatory test can be performed on the standard NBS dried blood spots, with no additional blood draw required.

Duchenne is currently under consideration to be added to the RUSP. In May 2024, the Advisory Committee on Heritable Disorders in Newborns and Children (ACHDNC) unanimously voted to postpone its decision for up to one year on whether to recommend Duchenne for inclusion on the RUSP until additional evidence is available to make a decision. PPMD is actively working with key opinion leaders (KOLs) and clinicians to bring forth additional data and we anticipate learning more from the states who have and will begin screening.

While the federal RUSP is an important tool to help create equality among state newborn screening programs, it remains only a recommendation regarding what conditions states should include for newborn screening. What’s more, with new treatments for many debilitating and fatal pediatric diseases becoming available, the RUSP has not been able to keep pace with science and innovation. While the best-case-scenario timeframe for a condition to be added to the RUSP is 18 months, on average it has taken 4 years for approved conditions to be added to the RUSP. In the 16 years since the RUSP was established, 16 conditions have been nominated for the RUSP, but only 8 have been approved. It typically takes several more years before states add the new conditions and screening begins—time children and families do not have.

An expert group of Duchenne clinicians developed and published clinical guidelines for care following a newborn screening diagnosis. After newborn screening, families consult with pediatric neuromuscular care teams to discuss the most appropriate treatment course for each child. They have the potential to initiate therapies such as exon skipping, gene therapy, and steroids years earlier than they would if diagnosed through traditional pathways. They may be able to enroll in clinical trials.

Establishing care in infancy also enables referrals to early intervention services such as speech, behavioral, physical, and occupational therapy. Newborn screening diagnosis has benefits for the family, including identifying at-risk family members, like carrier mothers who are at risk for cardiomyopathy and siblings who may be carriers or affected. Many families also report using this information in future family planning.