Achondroplasia is the most common type of dwarfism, caused by a mutation in the FGFR3 gene. It is characterized by an average height of 4 feet, with short arms and legs and a large head. It is inherited in an autosomal dominant pattern and causes disproportionate skeletal growth with bowed legs and short stature.

1. DWARFISM
(ACHONDROPLASIA)

2. ACHONDROPLASIA
 Literally means “without cartilage formation”
 Most common type of dwarfism.
 Caused by mutation of gene for (FGFR3)
 Average height is about 4 ft.
 Short arms and legs.
 Large head.

3.  Achondroplasia is one of a group of disorders called
chondrodystrophies or osteochondrodysplasias.
 May be inherited as an autosomal dominant trait, which means that
if a child gets the defective gene from one parent, the child will have
the disorder.

4. SIGNS AND SYMPTOMS
 Abnormal hand appearance with persistent space between the long
and ring fingers
 Bowed legs
 Decreased muscle tone
 Disproportionately large head-to-body size difference
 Prominent forehead

5.  Shortened arms and legs (especially the upper arm and thigh)
 Short stature (significantly below the average height for a person
of the same age and sex)
 Spinal stenosis
 Spine curvatures called kyphosis and lordosis

7. DENTAL CORRELATION
 The administration of thyroid hormone is known to accelerate
dental development and eruption
 His dental development is still extremely retarded and is
following a disturbed pattern in which various stages of dental
development are present simultaneously

8. SINGLE GENE
 It is considered as single gene because only the Fibroblast Growth
Factor Receptor Gene 3 is affected which is also important in the
maintenance of bone and brain tissues