Achondroplasia (Dwarfism)

Biology Research Project


I chose to do achondroplasia because my little cousin Mason Coffey who is in the 6th grade has this condition.


A form of short limbed dwarfism. In early development bones are still mostly cartilage. Ossification is the process that converts cartilage to bone. This is the problem that Achondroplasia (dwarfism) has, the cartilage doesn't convert correctly especially in the long bones of the arms and legs causing the short stature that is evident in people with dwarfism.


  • short stature
  • short arms and legs
  • Average height for females is 4'1'
  • Average height for males is 4'4'
  • limited range of motion at elbows
  • enlarged head
  • prominent forehead
  • short fingers

Common Problems

  • obesity
  • recurrent ear infections
  • lordosis (pronounces and permanent sway of the lower back)
  • Kyphosis (abnormal front to back curvature of the spine)
  • bowed legs

Facts I Learned

  • Achondroplasia is the most common type of short limbed dwarfism.
  • about 80% of people with this condition have normal sized parents.
  • 1 in every 200,000 are affected by dwarfism.
  • Dwarfs have the same life span as normal adults.
  • occurs equally among races and genders.
  • doesn't relate to location.


in 90% of cases dwarfism occurs as the result of a new spontaneous mutation in genetic material or it can be inherited.

How it is inherited

In normal sized parents achondroplasia occurs from mutations in the FGFR3 gene. In other cases the FGFR3 gene is inherited from one or both affected parents. It is inherited in an autosomal dominant pattern (the mutation occurs on the autosomes) . It is a non sex-linked disease. It is dominant.

Genes associated with Achondroplasia

FGFR3 Gene: Provides instructions for making proteins that are involved in the development and upkeep of bone and brain tissue.


There is no cure for dwarfism, but there are treatments to help relieve some of it's effects.

Corrective surgeries: Cleft palate, club foot, and bowed legs.

Physical therapy can help strengthen muscles and increase joint range of motion.


Achondroplasia can be confirmed through genetic testing, but can also be diagnosed at birth or infancy through a physical exam. However sometimes it goes unnoticed until later in a child's life and then exams are done.
Big image

Punnett Square

Genotype "TT" is a dwarf, Genotype "Tt" is a dwarf but a carrier of the normal gene, and genotype "tt" is normal.
Carys and George's story - a Genetic Disorders UK / Jeans for Genes Day film