Achondroplasia – Causes and Symptoms of Achondroplasia

Achondroplasia is a genetic disorder and is the common type of dwarfism where the child’s arms and legs are short in proportion to body length. The head is large and trunk is normal size.The average height of adult males with achondroplasia is 52 inches and the height of adult females is 49 inches. It is a disorder that affects about one in every 10,000 newborn. Neurological impairment is seen in about 20 to 50%.

What causes achondroplasia?

The causes of achondroplasia is as follows:

Gene Mutation

  • People suffering with achondroplasia have average size parents.
  • This means that in majority of cases a new mutation in the FGFR3 gene is seen.
  • The scientists are also not able to tell why this mutation occurs.
  • The protein that is made by the FGFR3 gene is a receptor that regulates bone growth which limits the formation of bone from cartilage.
  • Scientists believe that mutations in the FGFR3 gene cause the gene to be hyper-active.
  • This disturbs the ossification process and the bone growth is abnormal which results in this disorder.


  • If one parent is affected with achondroplasia, there are 50% of chances for the child to inherit the FGFR3 gene.
  • If both the parents are suffering from achondroplasia, the children have 1 in 4 chance of inheriting the defective gene.
  • Newborn babies who inherit both the genes have a very serious and severe form of achondroplasia.
  • These newborns survival rate is very low and in most of the cases it is less than 12 months.

Symptoms of Achondroplasia

The signs and symptoms for achondroplasia is as follows:

  • Short arms.
  • Small body size.
  • Normal size skull.
  • Short legs.
  • Normal size spine.
  • Normal sexual organs.
  • Normal intelligence.
  • Dwarfism.
  • Short thick arms.
  • Protruding forehead.
  • Short thick legs.
  • Large head.
  • Short thick legs.
  • Small face.
  • Depressed nasal bridge.
  • Stubby hands.
  • Short stature.
  • Lordosis.
  • Short finger.
  • Limited elbow motion.
  • Short middle finger.
  • Narrow nasal passages.
  • Mid facial hyperplasia.
  • Bulldog face appearance.
  • Reduced muscle tone.

Health Problems as Symptoms of Achondroplasia

The common health problems connected with achondroplasia are as follows:

  • Frequent ear infections.
  • Breathing disorder.
  • Obesity.
  • Adults with achondroplasia develop a permanent and pronounced curve in the back.
  • In older individuals, achondroplasia can cause back pain.
  • Due to back pain, patients have difficulty in walking.

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