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Achondroplasia is a disorder of bone growth. Achondroplasia literally means "without cartilage formation". The problem in this condition is converting the cartilage into bones, particularly the long bones. Achondroplasia is a genetic (inherited) condition that results in abnormally short stature. All persons with achondroplasia are little people. The average height of an adult with achondroplasia is 131 cm (52 inches, or 4 foot 4) in males and 124 cm (49 inches, or 4 foot 1) in females

Achondroplasia is one of the oldest known birth defects. An average figure worldwide is approximately 1 in 25,000 births..


The typical appearance of achondroplastic dwarfism can be seen at birth. Symptoms may include:Abnormal hand appearance with persistent space between the long and ring fingers

Bowed legs

Decreased muscle tone

Disproportionately large head-to-body size difference

Prominent forehead (frontal bossing)

Shortened arms and legs (especially the upper arm and thigh)

Short stature (significantly below the average height for a person of the same age and sex)

Spinal stenosis

Spine curvatures called kyphosis and lordosis

Signs and tests

During pregnancy, a prenatal ultrasound may show excessive amniotic fluid surrounding the unborn infant.

Examination of the infant after birth shows increased front-to-back head size. There may be signs of hydrocephalus ("water on the brain").

X-rays of the long bones can reveal achondroplasia in the newborn.


There is no specific treatment for achondroplasia. Related abnormalities, including spinal stenosis and spinal cord compression, should be treated when they cause problems.

Expectations (prognosis)

People with achondroplasia seldom reach 5 feet in height. Intelligence is in the normal range. Infants who receives the abnormal gene from both parents do not often live beyond a few months.


Clubbed feet

Fluid buildup in the brain (hydrocephalus)

Calling your health care provider

If there is a family history of achondroplasia and you plan to have children, you may find it helpful to speak to your health care provider.


Genetic counseling may be helpful for prospective parents when one or both have achondroplasia. However, because achondroplasia most often develops spontaneously, prevention is not always possible.


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