Definition:

Achondroplasia is the most common skeletal dysplasia and the most frequent cause of short-limbed dwarfism. It is usually recognised at birth because of its distinctive clinical and radiographic features. Newborn infants with achondroplasia typically present with disproportionate shortening of the limbs, a long and narrow trunk, a large head with frontal bossing and midface retrusion. This disease is caused by mutations of the transmembrane receptor FGFR3, an important regulator of bone growth. It is inherited in an autosomal dominant manner, but in the majority of cases it results from de novo mutations. The most common complications of achondroplasia are medullary and radicular compressions due to spinal stenosis and deformities of the lower limbs. Most individuals with achondroplasia have normal intelligence.