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JD3's Story: MUSC Health Medical Geneticist Leads Breakthrough Treatment for Infant with Spinal Muscular Atrophy (SMA)

Gary Logan
January 02, 2024
Smiling Infant

As a ninth grader, Neena Champaigne was first introduced to genetics in her biology class and her interests grew and evolved through the class and the years of training that followed. Exploring potential career paths, she knew she would never work 24/7 in a lab. “I really like people and didn’t see myself working in a lab fulltime, which didn’t offer the same interaction with patients,” she explains.

The blending of genetics—the study of genes and their effects—with pediatric practice deeply inspired Champaigne, which led her to the Medical University of South Carolina (MUSC) and its Shawn Jenkins Children’s Hospital. There she has been on the front lines of identifying and treating infants with serious and potentially life-threatening conditions early on, even before birth, to give them and their families hope for a full and healthy life in the future.

“As a medical geneticist I see a number of patients with birth defects, intellectual disabilities and metabolic conditions,” says Champaigne, “but my primary interest is in newborn screening and identifying infants who may have a genetic disorder that would be eligible for treatment.”

Newborn screening, in Champaigne’s 20 years of experience, has not only opened the door to early detection of genetic disorders but also to innovative treatments that target genetic alterations in such conditions. One patient who came through that door is John Dehaven Killman III, or JD3, the son of Christy and Johnny Killman of Conway, South Carolina. Through newborn screening and genetic tests, he was found to have Spinal Muscular Atrophy (SMA), a rare progressive motor neuron disease that affects voluntary muscle movement, including the ability to walk, eat and, ultimately, breathe. SMA affects approximately one in 10,000 individuals and is the leading genetic cause of death among infants.

Getting the news on a Friday and asked to come to the hospital on Monday for confirmation, Christy said her heart sank: “It was a very scary diagnosis and a grueling weekend. There were so many unknowns.” After looking up the genetic traits of SMA, Johnny said he felt “devastated.” As a religious couple, they say they relied on their faith to allay any fears. Learning about the value of newborn screening also helped.

Newborn screening is not as well known by a lot of patients and families like the Killmans, says Champaigne, and often when their child tests positive they were unaware that screening was happening. “It is a very emotional time when a family has a baby with a positive result, that then needs to be confirmed.”

No pediatrician enjoys giving a young patient and family such a serious diagnosis, but for Champaigne it was also a moment of optimism when she met with the family the following Monday to confirm their son’s diagnosis. While he carried Type 1 or 2 SMA, the most serious forms of the disease, she noted that JD3’s exam at four days old showed no physical signs of SMA, a disease in which the earlier the age of onset, the greater the impact on motor function. Although the treatments can rapidly increase SMN protein production after administration, some irreversible damage may have already occurred in the nervous system, even before a baby is born. But most encouraging, she says, was the addition of SMA to South Carolina’s list of conditions eligible for newborn screening in September 2022, enabling him to be screened and treated early. The timing was critical.

“I’ve taken care of patients with SMA throughout the course of my career but never had the opportunity to treat them,” says Champaigne. “That opportunity came with the implementation of newborn screening, early detection and available treatments.”

In fact, JD3 would be the first patient at MUSC to receive a new FDA-approved treatment that, while not a cure, had been shown to benefit children with SMA by increasing production of the Survival Motor Neuron (SMN) protein. Children with SMA are born with missing or malfunctioning SMN1 genes, which the treatment, a one-time infusion called Zolgensma, was designed to replace with a new, working copy of the gene. However, the gene therapy carries risks, including acute liver injury, liver failure and death, as it requires patients to be immune suppressed with steroids to allow delivery of a virus to deliver the gene.

“We wanted to feel peace about our decision, for our child to be the first to receive this treatment at MUSC,” says Christy. “How do we as parents know we’re making the right decision? I had that peace of mind that everything was going to be fine, that was our foundation, but we really didn’t know what would happen.”

JD3 arrived at MUSC for his scheduled infusion at four weeks and four days of age, as clinical trials have shown that the ideal time for the infusion is between four and six weeks. His parents were surprised at how many staff were in the room, 11 by Christy’s count. It appeared JD3’s care team had expanded.

Christy, Johnny & JD3 Killman smiling 
Christy, JD3 & Johnny Killman

“We also saw specialists in cardiology and neurology, who wanted to let us know they would help whatever the situation was,” says John. “There was this spirit about them—we realized there wasn’t just a genetic wing to this.”

Also present was a family coordinator from Novartis, the pharmaceutical company that developed the treatment. “There are a lot of anxieties and unknowns for families who go through this when a child looks healthy and normal,” says Champaigne. “It helps to have a non-provider, in this case a coordinator who is a mom who has a child with a genetic condition and who has attended hundreds of infusions, answer their questions.”

Christy, who held JD3 during the one-hour infusion, agrees: “She was there as a precaution to make sure we were all on the same page.”

All appeared to go well but the critical test would be signs of any significant side effects after the infusion, like liver enzymes gone awry, or physical signs of SMA, none of which appeared during the critical two-month post-infusion period. Since then, JD3’s family and Champaigne have been closely following his growth and development.

“He’s doing great, he has graduated from MUSC, we like to say. He still comes in for checkups and monitoring milestones, and he tried to impress me with a wide smile when he met his rolling over milestone early at three months,” says Champaigne. “He may need additional treatment along the way, but he’s developing normally now. Unique to the SMA story, there’s rarely ever a curative treatment but gene therapy could potentially be curative.”

Looking back five months out from JD3’s diagnosis of SMA, Christy commends both Jack’s care and the entire staff’s seemingly fortuitous support: “For us even to have our son at the hospital, to find the pediatrician we found and the connections to MUSC, was amazing. Dr. Champaigne and the staff helped us so much, cheerleading us through each of JD3’s milestones. We had no clue how this was going to work, but in time we felt they were as much a part of our journey as we were. We found friendship.”

Learn more about pediatric genetics at MUSC Children's Health, or schedule an appointment with a pediatric provider.