What Is Achondroplasia?
Achondroplasia is a skeletal dysplasia. Skeletal dysplasias (diss-PLAY-zhuhs) are conditions that cause problems with how cartilage and bone grow.
Children growing up with achondroplasia (ay-kon-druh-PLAY-zhuh) can live long, productive lives. Treatment can help with related problems, and new research offers hope for even better treatments.
What Are the Signs & Symptoms of Achondroplasia?
Children with achondroplasia have:
- dwarfism (height less than 4 feet, 10 inches [145 cm] as an adult)
- a large head
- a forehead that has an outward curve above the eyebrows (called frontal bossing)
- flattening of the part of the nose between the eyes (called midface hypoplasia)
- arms and legs that are short compared with the body
- elbows that are hard to straighten but loose joints everywhere else
- short, widely spread fingers
- bow legs (knees curve out) or knock-knees (knees curve in)
- a curved spine
- a narrowing of the foramen magnum (the opening at the bottom of the skull)
- a different timeline of motor development (later to sit, crawl, and walk than other kids)
Achondroplasia does not affect thinking and learning abilities.
What Problems Can Happen?
Health problems in achondroplasia can include:
- sleep apnea
- a lot of ear infections and/or fluid buildup
- an outward bend in a baby’s lower spine (thoracolumbar kyphosis)
- in adults: narrowing of the lower spinal canal (lumbar spinal stenosis) that can lead to pressure on the spinal cord (called cord compression) and cause back pain, leg weakness, and problems with peeing
- leg bowing that leads tripping and falling, or causes joint pain
What Causes Achondroplasia?
A gene mutation (change) causes achondroplasia. It makes bones grow slower and end up shorter than they typically would be.
A child can inherit achondroplasia if either parent has it. But most children born with it have a new (or spontaneous) genetic mutation that happened before birth, and neither parent has the condition.
A genetic counselor can help families understand how achondroplasia can run in families.
How Is Achondroplasia Diagnosed?
Doctors might diagnose achondroplasia before birth with a prenatal ultrasound, genetic testing (through amniocentesis), and/or chorionic villus sampling (CVS).
Most of the time, doctors diagnose it at birth or early in childhood. If a child is shorter than other kids the same age, or has short arms and legs, doctors do an exam and tests to find the cause. These tests usually include X-rays and sometimes genetic testing.
How Is Achondroplasia Treated?
There’s no cure for achondroplasia, but doctors and scientists are working on medicines that can help with bone growth. Gene therapies are also being studied.
A team of specialists cares for people with achondroplasia. They usually include:
Treatments may include:
- changes for everyday living, such as lower chairs with feet support, light switch extenders, and stools where needed
- ear tubes to help drain fluid from the ears
- weight management (after 2 years of age)
- back support for babies with thoracolumbar kyphosis
- sleep apnea treatment
- surgery to straighten the legs, straighten the spine, or ease narrowing of the spinal canal
Sometimes the care team will suggest avoiding activities that have a risk of neck injury such as contact sports, gymnastics, and trampolines.
When Should I Call the Care Team?
Call someone on your care team right away if your child:
- has a tense or hard fontanel (soft spot) on the top of the head (for babies)
- loses motor skills (for example, has stopped crawling, walking, or using one side of the body)
- complains of pain, tingling, numbness, or weakness in the arms or legs
- pauses breathing while asleep, or snores very loud or very often
- says “huh?” or “what?” a lot, or turns up the radio or TV louder than before, or seems like they can’t hear as well as before
- has pee or poop accidents (as a teen)
How Can Parents Help?
To help your child:
- Treat your child according to their age, not their size, and encourage others to do the same.
- Talk about achondroplasia as a difference rather than a problem. Your attitude can help your child develop good self-esteem.
- Find ways to adapt. For example, get a light switch extender and a stepstool so your child can turn the lights on and off. Encourage school staff to make similar changes that will help your child.
- Answer questions as simply as possible. If someone asks why your child is short, for example, say, “Santiago is shorter because his bones do not grow as fast as yours.” Then, mention something special about your child. For example, “Nothing holds Santiago back. He’s a great photographer.” This shows your child that many things make them special.
- Teach your child that being teased or bullied is not OK. If they're teased or bullied at school, work with your child, teachers, and administrators to end it.
- Check with your doctor about any sports your child should avoid.
What Else Should I Know?
Your child can live a full and happy life. Regular medical care will help them stay well and let doctors treat any health problems right away. Talk to anyone on the care team or a hospital social worker about resources that can help you and your child.
Support groups can be helpful for kids and their families. Ask the care team for recommendations. You also can find support and more information online at: