About Achondroplasia
Achondroplasia is caused by a gain-of-function mutation in the FGFR3 gene on chromosome 4, which encodes a receptor that normally limits bone growth. Nearly all cases (over 97%) involve the same specific mutation (G380R), making it one of the most genetically uniform rare diseases. The overactive FGFR3 receptor suppresses growth plate activity in the long bones, leading to shortened limbs while the trunk grows to near-normal size.
Beyond short stature, achondroplasia causes significant medical complications that require lifelong monitoring. Foramen magnum stenosis (narrowing at the base of the skull) is a serious concern in infancy that can compress the brainstem and spinal cord. Spinal stenosis develops in most adults and is the leading cause of pain and disability. Sleep apnea from midface hypoplasia affects a large proportion of children and adults. Hydrocephalus, recurrent ear infections, and obesity are additional concerns. In 2021, the FDA approved Voxzogo (vosoritide), a C-type natriuretic peptide analog developed by BioMarin that counteracts the overactive FGFR3 signaling to promote bone growth in children with open growth plates. This was the first drug approved specifically for achondroplasia.
Common Symptoms of Achondroplasia
Recognizing the signs of Achondroplasia early can lead to faster diagnosis and better outcomes. Symptoms may vary in severity from person to person. If you or a loved one are experiencing any of the following, consider speaking with a specialist.
- Short stature with disproportionately short arms and legs, especially upper arms and thighs
- Large head (macrocephaly) with prominent forehead and flattened nasal bridge
- Limited elbow extension and reduced range of motion at multiple joints
- Bowed legs (genu varum) that worsen with walking
- Exaggerated lower back curve (lumbar lordosis) with prominent abdomen
- Spinal stenosis causing back pain, leg weakness, and numbness in adulthood
- Obstructive sleep apnea from midface underdevelopment
- Recurrent middle ear infections and conductive hearing loss in childhood
- Delayed motor milestones, with walking typically starting at 18 to 24 months
- Dental crowding from smaller jaw size
Who Achondroplasia Affects
Achondroplasia is present from birth and affects males and females equally across all racial and ethnic groups. About 80% of cases are de novo mutations in parents of average height, with a strong association with advanced paternal age.
The remaining 20% are inherited from an affected parent in an autosomal dominant pattern. Average adult height is approximately 4 feet 4 inches for males and 4 feet 1 inch for females.
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FDA-Approved Treatments for Achondroplasia
There is currently 1 FDA-approved medication for Achondroplasia. These therapies represent the current standard of care and may be used alongside or compared against investigational treatments in active clinical trials.
Source: openFDA drug labeling data. This list may not include all treatments. Always consult your doctor.
Help Paying for Achondroplasia Treatment
Charity funds and drugmaker programs for Achondroplasia, checked at the source. Pick your insurance to see what fits.
- From a charity · Little People of AmericaGrant for Overall Accessible Living (GOAL) fundOpen
Pays for: Mobility devices and occupational tools (partial cost; LPA membership required).
The foundation says: “Applications are being accepted for the GOAL Fund.”
Side Effect Explorer
Real-world side effect reports from the FDA Adverse Event Reporting System (FAERS). Includes both FDA-approved drugs and investigational therapies from active clinical trials. Click any drug to see what patients reported.
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Genetic Testing
Genetic testing can confirm a diagnosis, guide treatment decisions, and identify family members who may be at risk.
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Trusted Achondroplasia Resources
Reputable organizations and medical references for learning more about Achondroplasia, including disease registries, foundation resources, and clinical guidelines.
