Achondroplasia: Symptoms & Signs

Medically Reviewed on 5/5/2021

Achondroplasia or short-limbed disproportionate dwarfism is a genetic disorder of bone growth and the cause of the most common type of dwarfism. It occurs in around one out of every 25,000 births worldwide.

Signs and symptoms of achondroplasia include short stature with disproportionately short limbs. Other signs include a

  • large head with prominence of the forehead (frontal bossing),
  • underdevelopment (hypoplasia) of the midface with cheekbones that lack prominence,
  • narrow nasal passages with a low nasal bridge,
  • short fingers,
  • the ability of many joints to extend beyond the normal range, and
  • an excessive inward curvature (lordosis) of the low back.

Cause of achondroplasia

Achondroplasia can be inherited as a dominant trait, but the majority (80%) of cases are due to new mutations, meaning neither parent has achondroplasia.

Other achondroplasia symptoms and signs

  • Ability of Many Joints to Extend Beyond the Normal Range
  • Excessive Inward Curvature (Lordosis) of the Low Back
  • Large Head with Prominence of the Forehead (Frontal Bossing)
  • Narrow Nasal Passages with a Low Nasal Bridge
  • Short Fingers
  • Short Stature with Disproportionately Short Limbs
  • Underdevelopment (Hypoplasia) of the Midface with Cheekbones That Lack Prominence

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Jameson, J. Larry, et al. Harrison's Principles of Internal Medicine, 20th Ed. New York: McGraw-Hill Education, 2018.