May also be called: Achondroplastic Dwarfism; Skeletal Dysplasia Achondroplasia (ay-kon-druh-PLAY-zhee-uh) is a genetic disorder that interferes with bone growth and causes dwarfism (short stature). More to Know During a baby's development in the womb, much of the skeleton is made up of a tough, flexible tissue called cartilage. Normally, cartilage is converted to bone by a process called ossification. With achondroplasia, the body has a problem growing cartilage and converting it to bone, especially in the long bones of the arms and legs. This results in shorter bones, short stature, and often a large head with a prominent forehead. It can also cause knock-knees, bow-leggedness, or excessive curving of the lower back (lordosis or kyphosis). Achondroplasia is the most common cause of dwarfism. It happens because of a mutation in a gene that develops and maintains bone tissue. Achondroplasia can be inherited from a parent, but in most cases, the mutation in the gene happens at random. Most people with achondroplasia have normal-sized parents. Since achondroplasia is due to a genetic mutation, those who have it may pass it on to their children. It can be diagnosed prenatally by ultrasound or genetic testing. There is no specific treatment for achondroplasia, but treatment might be necessary if it leads to complications such as hydrocephalus (fluid collecting around the brain), obesity, or spinal stenosis (narrowing of the spinal canal). Keep in Mind There is no cure for achondroplasia, but it does not affect a person's intellectual ability or life span. All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts. Back to Articles Related Articles A to Z: Kyphosis, Congenital Learn more about congenital kyphosis, an abnormal rounding of the spine that develops before birth. Read More Blount Disease Blount disease is a growth disorder that causes the bones of the lower leg to bow outward. This gets worse if it's not treated, so early diagnosis is very important. Read More Blount Disease Blount disease is a growth disorder that affects the bones of the lower leg. It causes bowing of the leg below the knee, which gets worse if it's not treated. Read More A to Z: Pituitary Dwarfism Pituitary dwarfism is a condition in which the pituitary gland does not make enough growth hormone, resulting in a child's slow growth pattern and unusually small stature. Read More A to Z: Osteodystrophy Learn about complications of kidney and liver disease and conditions that affect bone development. Read More Kyphosis Your spine, or backbone, normally curves forward gently as it runs up your back. Sometimes, though, someone's back can be rounded too far forward, which is a condition known as kyphosis. Read More A to Z: Genu Valgum Learn about common childhood orthopedic conditions and conditions that affect the legs and knees. Read More Growth Problems In most cases, teens who are small are just physically maturing a bit more slowly than their friends. Occasionally, though, there's a medical reason why some kids and teens stop growing. Find out about growth problems and how doctors can help. Read More Dwarfism Dwarfism is characterized by short stature. Many of the possible complications of dwarfism are treatable, and people of short stature lead healthy, active lives. Read More Dwarfism A dwarf is a short-statured person whose adult height is 4 feet 10 inches or under. Find out what happens when a person has dwarfism and why some people are born with it. Read More Prenatal Tests: FAQs Every parent-to-be hopes for a healthy baby, but it can be hard not to worry. Find out what tests can keep you informed of your health — and your baby's — throughout pregnancy. Read More Kyphosis Everyone's spine is slightly rounded forward at a gentle angle. If this angle is too pronounced, more than 50 degrees or so, it's called kyphosis, also known as roundback or hunchback. Read More All About Genetics Read the basics about genetics, including how certain illnesses, or increased risks for certain illnesses, pass from generation to generation. Read More Genetic Testing Advances in genetic testing help doctors diagnose and treat certain illnesses. The type of test done depends on which condition a doctor checks for. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.