Proposals exploring the feasibility and advisability of implementating newborn screening for two disorders in MDA's program — Duchenne muscular dystrophy and Pompe disease — were presented to a federal advisory committee in a "virtual" meeting Jan. 31 and Feb. 1, 2013.
The audio and slide presentations of these two proposals are now available online without charge. Below are summaries of both the Pompe and Duchenne muscular dystrophy (DMD) proposals to the newborn screening advisory committee.
What is newborn screening?
In the United States, newborns are screened for a variety of diseases that can be detected at birth and for which early treatment — before obvious symptoms appear — is available and judged to be beneficial.
Each individual state decides which disorders it will screen for based on recommendations from the U.S. Department of Health and Human Services (HHS).
HHS recommendations are based in large part on the advice of the Secretary's Advisory Committee on Heritable Disorders in Newborns and Children (SACHDNC) — the committee that heard the Pompe and DMD screening proposals outlined below.
Pompe newborn screening: ‘A question of days’
Pompe disease symptoms can begin at birth, or during childhood or adulthood, and can cause profound weakness of the skeletal and cardiac muscles. In the infantile form, the disease is often fatal within the first few months or years of life because of cardiac or respiratory muscle impairment. The late-onset form causes weakness of arms, legs, trunk and respiratory muscles.
Pompe, also known as acid maltase deficiency, is caused by a deficiency of the GAA (acid maltase) enzyme, leading to an accumulation of glycogen in cellular structures called lysosomes. Lifesaving enzyme replacement therapy (Myozyme) has been available for Pompe disease since 2006.
Pediatrician Alex Kemper from Duke University gave the Pompe disease presentation at the SACHDNC meeting on Jan. 31, 2013.
In addition to Kemper, Priya Kishnani, a pediatrician and medical geneticist at Duke University who has a special interest in Pompe disease and has received MDA funding to study it, also testified in favor of newborn screening so that treatment with enzyme replacement therapy can be started as early as possible.
"In the past, even for the infantile-form of the disease, we always took that starting babies [on enzyme replacement therapy] under 6 months of age was a good thing to do," Kishnani said. "It is true that the outcome was changed in the first months and years. But now we know that even this is too late. Some children are not doing as well as they should have done. In infantile Pompe disease, the need for treatment is not a question of weeks or months; it's a question of days. There's a difference between three days after diagnosis and eight days after diagnosis."
Summary of Pompe newborn screening proposal
Kemper made the following points in his presentation:
The SACHDNC may make a decision about whether to add Pompe disease to the list of conditions for which screening is recommended either prior to or after the next meeting of the committee, tentatively scheduled for May 2013.
Two-step DMD screening proposal
Neurologist Jerry Mendell, a longtime MDA research grantee and co-director of the MDA Clinic at Nationwide Children's Hospital in Columbus, Ohio, gave the DMD presentation at the second day of the SACHDNC meeting, Feb. 1, 2013.
Mendell has a strong interest in newborn screening for DMD. In January 2012, he and several colleagues published a paper describing a plan for large-scale implementation of a two-stage newborn screening process for DMD.
The two-step process involves screening all newborn babies for markedly elevated levels of blood creatine kinase (CK), an enzyme that leaks out of damaged muscle cell. In the first step, a dried blood spot (obtained by pricking the infant’s heel) would be tested for CK. If the infant has a very high CK level, the same dried blood spot would be used to conduct DNA testing for DMD-causing mutations in the dystrophin gene.
At an MDA symposium on newborn screening last fall, Mendell presented more details about his proposed plan to a blue-ribbon panel of physicians and researchers, patient advocacy groups, federal agencies, and others, including members of the SACHDNC.
Summary of DMD proposal for newborn screening
Mendell made the following points in his presentation to the SACHDNC in February:
Mendell said the goal of his presentation was to promote discussion of DMD newborn screening, and that he would like to come back to the SACHDNC at a later time to make a "formal nomination" to add DMD to the list of conditions recommended for newborn screening.
The committee was receptive to this idea.
Audio and slide presentations
Audio of both Kemper’s and Mendell’s presentations, plus the slides they showed the committee, can be accessed on the SACHDNC site (select Twenty-Ninth Meeting and then Audio Archives and Transcripts).
The Pompe presentation can be found in the afternoon session of Day 1 (Jan. 31, 2013) at about two minutes into the meeting.
The DMD presentation can be found on Day 2 (Feb. 1, 2013).
The next (30th) meeting of the SACHDNC is tentatively scheduled for May 16-17, 2013. The 31st meeting is tentatively scheduled for Sept. 19-20, 2013.