Definition of Achondroplasia:

Achondroplasia is a genetic disorder characterized by abnormal bone growth, resulting in dwarfism.

Subtypes:

Achondroplasia can be classified into two subtypes:

  • Classic Achondroplasia: This is the most common subtype, accounting for approximately 80% of all achondroplasia cases. It is characterized by short stature, disproportionately short limbs, an enlarged head with a prominent forehead, and a normal lifespan.
  • Atypical Achondroplasia: This is a rarer form of achondroplasia that presents with a milder phenotype. Individuals with atypical achondroplasia may have normal or near-normal stature and fewer skeletal abnormalities compared to classic achondroplasia.

Cause:

Achondroplasia is caused by a mutation in the FGFR3 gene. This gene provides instructions for making a protein that is involved in the development and maintenance of bone and brain tissue. The specific mutation in FGFR3 leads to abnormal bone growth, particularly in the long bones of the arms and legs.

Symptoms:

Common symptoms of achondroplasia may include:

  • Short stature: Individuals with achondroplasia typically have a height significantly below average for their age.
  • Disproportionate limbs: The arms and legs are usually shorter compared to the trunk of the body.
  • Enlarged head: The head may be larger than average, with a prominent forehead.
  • Spinal abnormalities: Some individuals may develop a condition called spinal stenosis, which can lead to compression of the spinal cord.
  • Joint problems: Joint stiffness and limited range of motion are common in achondroplasia.
  • Respiratory problems: Infants and young children with achondroplasia may experience breathing difficulties due to narrow airways.

Treatment:

While there is no cure for achondroplasia, medical management focuses on addressing associated health issues and supporting normal development. Treatment options may include:

  • Regular medical evaluations and monitoring of growth and development.
  • Physical therapy to improve muscle strength and flexibility.
  • Surgical interventions, such as spinal decompression, if spinal stenosis is severe.
  • Management of complications, such as respiratory infections or orthopedic problems.
  • Genetic counseling to understand the risk of passing achondroplasia to offspring.