Definition

Achondroplasia (ACH) is a genetic bone disorder. It is the most common type of dwarfism. Key features are a large head, short limbs, a narrow chest, and short fingers.

Causes

Causes may be:

  • Changes in the FGFR3 gene
  • Advanced age of father

Risk Factors

This problem can happen in people who do not have any known risk factors.

The gene changes can also be passed through a family, though this is not as common.

Symptoms

Problems are often seen at birth. Key features are a large head, short limbs, a narrow chest, and short fingers.

Other problems may be:

  • Short stature—adult height will be 4 to 4½ feet
  • Bowlegs
  • Short toes
  • Underdeveloped parts of the face
  • Arms that may not be fully straight at the elbow
  • An excessive lower back curve

Diagnosis

A prenatal ultrasound may point to ACH. Genetic testing may be done to confirm it.

ACH may also be suspected during a physical exam at birth. It can be confirmed through x-rays. Rarely, genetic testing may be done if the exam and x-rays are not certain.

Treatment

There is no cure. The goal of treatment is to manage related health problems. Choices are:

  • Medicine, such as human growth hormone to increase adult height
  • Surgery to treat health problems, such as:
    • Spinal fusion to connect spinal bones to make them more stable
    • Laminectomy to remove parts of spinal bones to ease pressure on the spinal cord
    • Osteotomy to repair severe bowlegs
    • Bone lengthening to cut and divide a bone to encourage more growth
  • Counseling and support groups
Spinal Stenosis
Stenosis of spine with punched nerve

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Prevention

There are no known guidelines to prevent ACH.

RESOURCES:

Healthy Children—American Academy of Pediatrics
http://www.healthychildren.org

Little People of America
http://www.lpaonline.org

CANADIAN RESOURCES:

Caring for Kids—Canadian Paediatrics Society
http://www.caringforkids.cps.ca

Little People of Ontario
http://www.lpo.on.ca

REFERENCES:

Achondroplasia. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/achondroplasia. Accessed October 29, 2020.

Achondroplasia. Genetic and Rare Diseases Information Center website. Available at: https://rarediseases.info.nih.gov/diseases/8173/achondroplasia. Accessed October 29, 2020.

Pauli, RM, Legare JM. Achondroplasia. GeneReviews 2018 May 10.

Last reviewed September 2020 by EBSCO Medical Review Board James P. Cornell, MD  Last Updated: 10/29/2020