How Do You Treat Hypochondroplasia?

“The goal is not simply to increase a number on a growth chart,” says Joshua H. Yang, MD, the chief of pediatric endocrinology at Orlando Health Children's in Florida. “It is to optimize health, mobility, comfort, participation, independence, and quality of life, while ensuring that children and families have accurate information and meaningful choices.”

Growth Hormone Therapy

“Growth hormone works at the earliest portion of the growth plate called the resting zone, which is where there are cells waiting for a signal from the body to divide and start to grow,” says Dr. Lombardo. But hypochondroplasia blocks bone cells from moving to other zones, she says.

This happens because of a change in the FGFR3 gene. Overactive FGFR3 messages “shut down” the ability for cells to move through zones, says Lombardo. So, when you give growth hormone, it tells your cells to grow and make bone, but then those cells get stuck between zones, says Lombardo. “Even if we give extra growth hormone, it’s not enough to get past this block.”

• Growth pattern
• Predicted adult height
• Bone age
• Puberty timing
• Body proportions

Yang also checks for true growth hormone deficiency or other treatable reasons for poor growth.

Orthopedic Interventions and Surgical Care

• Body proportions
• Growth speed
• Sleep
• Breathing
• Learning
• Joint function
• Mobility
• Pain

“Surgery is considered when there is a specific functional or structural problem,” says Yang, who gives these examples.

• Severe bowing of the legs
• Leg misalignment
• Uncontrolled pain
• Trouble walking
• Lower endurance
• Worsening spinal curves
• Hip or knee problems
• Neurological symptoms from spinal stenosis (like pain, numbness, tingling, and bowel or bladder changes)

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Managing Bowed Legs

“If the degree or severity of bowing is significant, a procedure such as guided growth can be used to help correct this as the child grows,” says Lombardo.

During this surgery, your child’s surgeon places a small metal plate and two screws on one side of the growth plate through a small incision on the affected side, says Lombardo. “This slows down growth on that side while the other side keeps growing normally.”

Over about 12 months, the bowing straightens out, and they can have the plate removed, she says.

Spine Surgery

Limb‐Lengthening Surgery

Limb-lengthening surgery can increase limb length, adult height, and reach, says Yang. “But it requires a long commitment: staged surgery or procedures, intensive rehabilitation, and careful management of risks.”

This surgical option is uncommon for hypochondroplasia and is usually reserved for people with a severe difference in leg length or trouble using their arms, says Lombardo.

Precision Medicine and Emerging Clinical Trials

“Two medications, vosoritide and navepegritide, are under investigation for hypochondroplasia and are expected to receive FDA approval in the near future,” says Lombardo.

These are the medications being researched for hypochondroplasia and how they work:

• Vosoritide (Voxzogo) mimics c-type natriuretic peptide (CNP) — a chemical messenger that can dampen the effects of FGFR3 changes. One study of 24 children showed that vosoritide increased yearly growth speed by about 0.7 inches per year in children with hypochondroplasia. Vosoritide is given as a daily injection.

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• Navepegritide (Yuviwel) works in the same way as vosoritide, but releases CNP slowly. This medication is given by injection once a week.

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   Experts are investigating the possibility that navepegritide might work for hypochondroplasia, but no clinical trials have started yet.

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• Infigratinib (Truseltiq) blocks the FGFR3 receptor directly, restoring balance at the growth plate, says Lombardo. This medication was given by mouth in animal studies, but human trials are needed to learn the best dosage and its effectiveness in humans.

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Lifestyle Support and Symptom Management

Pain Management

Sleep Apnea Treatment

Seizure Prevention