Advances in the Diagnosis and Management of Rare Disorders - Episode 9

Duchenne Muscular Dystrophy and its Treatment Options

In this segment, the panel turned its attention to Duchenne muscular dystrophy, which affects just one in every 3500 male births according to moderator Abhimanyu Garg, MD. That equates to 20,000 new cases every year.

Garg noted that the condition can be hereditary but that “approximately 35% of cases occur because of a random spontaneous mutation in the gene.” As the patient’s muscles weaken it can make them susceptible to other health concerns like cardiomyopathy. He also said the life expectancy for a young male with the disease is likely only into their early 20s.

While there is no known cure for Duchenne, Garg said there are “experimental agents” that have shown signs of success in clinical trials. “These are exciting developments which are going on in the area of Duchenne muscular dystrophy,” he noted.

When asked about early signs and symptoms of the condition, Patricia Furlong, founding President and CEO of Parent Project Muscular Dystrophy, noted that at times a family history can tell a lot about a patient’s chances of having this form of muscular dystrophy. That includes the child having “head lag.”

“So when you pull him up by both arms, he wouldn’t naturally curl his head. So you would notice that at first,” she said. “You would also note delayed motor milestones. So this child would be going on the trajectory of following milestones but just a little bit delayed from his health peers.”

Other symptoms could include a “waddling gate,” according to Furlong, as well as issues with jumping and struggling on stairs. Eventually, she said, the patient would lose the ability to walk or move their arms before suffering from respiratory issues, “and often they die of heart failure.”

Susan Winter, MD, FAAP, FFACMG, said finding out a young boy has the condition can be a “devastating diagnosis to tell someone.”

“It’s one of the more common disorders that gets referred to my clinic where the family has no idea why they’ve been sent to genetics,” she added. “And one thing I think you need to know as a primary care is you really do need to tell people what you’re worried about and that you’re sending them to a specialist. Because it’s so devastating for the families with this disease to not know why they’re even there.”

As for tests that can be done, Vanessa Rangel Miller, MS, CGC, MBA, said there are some options to assist in the diagnosis of the rare condition.

“It’s among the few rare conditions where we can find both the underlying genetic causes pretty reliably and understand the meaning of the genetic cause reliability,” she said.

Testing can include looking for deletions in duplications as part of “underlying genetic changes,” according to Miller. “If we don’t see a deletion or duplication we can look for a point mutation using sequencing technologies.”