Achondroplasia is a genetic disorder that causes dwarfism (short
stature). It is a disorder in which bone and cartilage do not
grow normally. It is the most common cause of dwarfism. This
condition leads to patients reaching a full-grown height of less
than four feet. The greatest shortening occurs in the humerus
(the bone between the shoulder and the elbow) and the femur (the
bone between the hip and the knee). There may also be
underdevelopment of the face. Achondroplasia is the most common
form of inherited disproportionate short stature. It occurs in
one in 26,000 to one in 40,000 live births. Achondroplasia is a
genetic disorder. It is caused by mutations in the FGFR3 gene.
This gene prevents the growth of cartilage at the growth plate.
FGFR3 encodes a protein called Fibroblast Growth Factor Receptor
3. This protein is the site of action of a major growth factor
responsible for lengthening bones. When this growth factor
cannot act properly due to the absence of its receptor, the
growth of bones, at the g