About 1 in 20,000 babies every year are born with achondroplasia, a rare genetic condition that causes short stature. People with achondroplasia usually live long, healthy lives, although they are more at risk for certain health complications. But treatment and management has greatly improved over the last couple of decades.
“We’ve gained a lot more understanding about achondroplasia, which has made us much better at managing it,” says Ricki Carroll, MD, a complex care and palliative care pediatrician at the Nemours Children’s Hospital in Delaware.
In addition, advances in treatment options — including medications and surgery — improve health outcomes. Here’s a look at some of the most recent advances in achondroplasia.
New, Revolutionary Treatments
For years, there were no medications available to treat achondroplasia. But in 2021, the FDA approved the use of vosoritide (Voxzogo) to improve growth in children ages 5 and older with open growth plates (which means they’re still able to grow). The ability to use vosoritide was extended to kids of all ages (starting at birth) with achondroplasia and open growth plates in late 2023.
Vosoritide is a type of drug known as a C-type natriuretic peptide (CNP) analog. It boosts cartilage cell growth, which in turn leads to increased bone growth.
“People with achondroplasia have a mutation in the FGFR3 gene, which helps to regulate growth,” Carroll says. “I explain to patients and their parents that the mutation is like driving with the emergency brake on. Voxzogo acts like a gas pedal to try to accelerate bone growth.”
Studies show that kids who take the drug, which is given as a daily shot, grow about 1.5-2 centimeters more each year than those who get a placebo.
But vosoritide may also offer more health benefits. New research suggests it may reduce the risk of developing bowed legs, a common complication of achondroplasia that can cause leg pain and trouble walking.
“We want data beyond height,” says Nadia Merchant, MD, a pediatric endocrinologist and geneticist in Dallas, Texas who specializes in achondroplasia. “We want to know: If kids start at birth on this drug, will they need less surgery in the future?”
There are three other drugs in clinical trials to treat achondroplasia.
While all these drugs work in a similar way to vosoritide, the hope is to give kids and their parents more accessible options.
“It’s hard to give all kids who want treatment a daily injection,” Merchant says. “If we can drop down to weekly, or even give children a pill, it may be easier for them to stick to treatment.”
Surgical Advancements
People with achondroplasia are more likely to develop musculoskeletal complications that need surgery, such as bow legs or spinal stenosis. But there have been some updates on how doctors handle those surgeries, as well.
Bow legs correction
To help with bow legs, doctors have traditionally relied on osteotomy, a surgery where the shin or thigh bone is cut and realigned. But today, many surgeons instead use guided growth surgery. It’s less invasive and requires less recovery time. During the procedure, a surgeon inserts small, metal plates about the size of a paper clip into the side of the growth plate that’s growing faster than the other.
“It allows the other side to catch up and straighten out the leg naturally using its own growth,” Carroll says.
It’s removed after 12 to 24 months.
Spinal stenosis
Many people with achondroplasia have spinal stenosis, a narrowing of the spine that puts pressure on the nerves and spinal cord and causes pain.
“This is because historically, doctors have only fused a small segment of the spine because of the fear that if they fuse too much, the patients will lose a lot of their ability to bend, twist, and lift,” says Arun Hariharan, MD, a pediatric orthopedic surgeon at the Paley Orthopedic and Spine Institute in West Palm Beach, Florida.
His research has found that surgery that fuses a longer section of the spine, including the lower segments, has a higher success rate.
“We have found the best results with an anterior fusion, where we fuse spinal vertebrae together with an abdominal incision,” he says. “We then insert a bone graft inside a ‘cage’ in the front part of the spine to give it additional support.”
Better Insights Into Complications
For years, doctors were mystified as to why children under the age of 5 with achondroplasia were almost 50 times more likely to experience sudden death than other young children without the condition. We now know that it’s due to foramen magnum stenosis, or a narrowing of the opening at the base of the skull where the spinal cord passes through. Today, it’s recommended that all babies with achondroplasia have neuroimaging and a sleep study done at least once in their first year of life.
In 2021, the American Academy of Pediatrics also published new medical guidelines for people with achondroplasia.
“Up until recently, we didn’t even have accurate growth charts for kids with achondroplasia,” Merchant says. “But thankfully, since we understand the condition a lot more, we can do routine management to look for complications like sleep apnea, hearing loss, or musculoskeletal problems.”
Noninvasive prenatal testing
Until recently, the only way to know for certain whether or not your baby had achondroplasia during pregnancy was to undergo invasive prenatal testing like amniocentesis. But over the last several years, blood tests have become available that can detect up to 96% of cases prenatally.
“This way, if a pregnant patient has an ultrasound that suggests achondroplasia, she can get the test done and be prepared,” says Merchant.
Doctors may see signs of achondroplasia during a routine pregnancy ultrasound. Signs include:
- Short limbs
- Short hands and fingers
- Large head with a prominent forehead
- Flat nasal bridge
- A curvature of the spine in the lower back
Coordination of Care
Over the last couple of decades, centers to manage achondroplasia have sprouted up across the country. When visiting these centers, people with achondroplasia are often seen by a multidisciplinary team. Their care team may include:
- Complex care pediatricians
- Geneticists and genetic counselors
- Orthopedic specialists
- Ear, nose, and throat doctors
- Pulmonologists
- Neurosurgeons
- Endocrinologists
- Nutritionists
As a complex care pediatrician, Carroll considers herself the quarterback of each of her patients’ medical teams.
“There’s a real emphasis now on thinking about each patient medically from head to toe through an achondroplasia lens,” Carroll says. “One of my jobs is to make sure we’re not missing anything and we’re caring for the full child.”
Many people with achondroplasia and their families visit a skeletal dysplasia clinic once a year. then get follow-up care with their care team closer to home, says Merchant. Organizations such as Little People of America often have a list of skeletal dysplasia clinics on their website for families.
A Growing Acceptance
Organizations like Little People of America have been around for more than half a century, but acceptance of people with conditions like achondroplasia has still taken decades to achieve, says Caroll.
“I tell every single parent who comes to see me that their child will go on to become a healthy, happy, functioning adult who can get married, have kids, and join any profession, as well as be part of the community,” Carroll says.
Thanks to new medical treatments and advances in awareness, especially when it comes to achondroplasia complications, the future for people with this condition has never looked brighter.
“Achondroplasia is no longer viewed as a disease — It’s simply another condition some people are born with,” Carroll says. “People with achondroplasia don’t need anything to ‘fix’ them so that they can enjoy a good quality of life and serve as functional, fabulous members of their community.”