Achondroplasia, also known as dwarfism, is a condition that causes abnormal bone growth and development. The condition is present at birth (congenital), and most people with achondroplasia will not grow to an average adult height. It is the most common abnormality of bone growth.
Achondroplasia affects the development and growth of cartilage and bone. It most noticeably affects the skull, spine, and arm and leg bones, causing those bones to be short or irregularly shaped. Achondroplasia occurs as often in boys as in girls, and the features and traits are similar in boys and girls. It is not more common in any particular ethnicity. It does not affect intelligence but may be associated with other medical problems.
What are the causes?
Achondroplasia is caused by an abnormal gene. This is also called a mutated gene. In most cases, this gene mutation happens on its own. In some cases, the mutated gene may be passed from parent to child (inherited).
What increases the risk?
Their father was 50 years old or older when their mother became pregnant.
One or both of their parents have achondroplasia.
What are the signs or symptoms?
Shorter arms, legs, toes, and fingers than expected for a baby of his or her size.
Floppy movements. This is a sign of decreased muscle tone.
A larger-than-normal head with a large forehead (frontal bossing).
Legs that curve slightly outward at the knee (bowed legs).
A wide space between the fingers, known as trident hand.
Delayed development in sitting, standing, and walking.
Frequent ear infections.
A large head due to fluid buildup in the brain (hydrocephalus).
Prolonged pauses in breathing followed by gasping (apnea).
Pain, numbness, or tingling in the low back, or loss of bladder control. These symptoms are caused by narrowing of the spine.
A curved or hunched back.
How is this diagnosed?
A child may be diagnosed with achondroplasia before birth or soon after birth.
A routine ultrasound may show short bones and too much fluid in the womb (amniotic fluid).
If an ultrasound suggests achondroplasia, a procedure may be done to collect a sample of amniotic fluid (amniocentesis). The fluid is tested for the gene mutation.
A blood test to check for the gene mutation.
X-rays of the skull, spine, and limbs.
Imaging tests, such as CT scan or MRI, to look for abnormalities of the spine or spinal cord.
How is this treated?
Surgery or physical therapy to treat problems with the bones.
Inserting a small tube (surgical drain) to drain fluid from the brain into the abdomen. This tube is called a ventriculoperitoneal (VP) shunt. This may be done to treat hydrocephalus.
Having other treatments as needed, such as for complications like sleep apnea.
Follow these instructions at home:
Eating and drinking
Make sure your child stays active and eats a healthy diet.
If your child is overweight, ask your child’s health care provider for nutrition advice.
Make sure your child has good back support when he or she rides in a car seat or stroller. This may help prevent back problems.
If you or your child are having a difficult time managing your feelings about achondroplasia, work with a licensed counselor, psychologist, or support group. Your health care provider may be able to recommend a therapist or support group.
Learn as much as you can about achondroplasia and how to manage it.
Monitor your child’s symptoms. Let your child’s health care provider know about any changes in your child’s health.
Where to find more information
Understanding Dwarfism Program: www.udprogram.com
Little People of America: www.lpaonline.org
The Child Growth Foundation: childgrowthfoundation.org
Contact a health care provider if:
Your child has apnea. This may look and sound like your child stops breathing for a few seconds, and then starts inhaling loudly.
Your child has ear pain. Pulling or tugging on the ear may be a sign of ear pain.
Your child seems to have trouble hearing.
Get help right away if:
Your child has trouble breathing.
Your child complains of (or shows signs of) sudden or worsening headaches.
These symptoms may represent a serious problem that is an emergency. Do not wait to see if the symptoms will go away. Get medical help right away. Call your local emergency services (911 in the U.S.). Do not drive yourself to the hospital.
Achondroplasia, also known as dwarfism, is a condition that causes abnormal bone growth and development.
Achondroplasia most noticeably affects the skull, spine, and arm and leg bones, causing those bones to be short or irregularly shaped. Most people with achondroplasia will not grow to an average adult height.
This condition is caused by an abnormal (mutated) gene. In most cases, this gene mutation happens randomly (spontaneously), but in some cases, the mutated gene may be passed from parent to child (inherited).
There is no cure for achondroplasia, but treatments are available to help with issues related to the condition. Treatments may include surgery or physical therapy to treat problems with the bones, or having surgery to treat hydrocephalus.
This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.