Achondrogenesis Type II (ACG2, Langer-Saldino) [Q77.0]
Dr. rer. nat. Christoph Marschall
Achondrogenesis is a disorder that leads to neonatal dwarfism. It is generally a lethal condition with death in utero or during the early neonatal period due to pulmonary hypoplasia. The incidence is estimated to be 1 in 40,000. The average birth weight of affected newborns is only around 2,000 g. It is characterized by striking micromelia dwarfism, disproportionally large head, prominent forehead, small nose, micrognathia, a short neck and narrow thorax, micromelia, protuberant abdomen and markedly deficient ossification of the vertebral column, sacrum and pubic bones.
The disease is usually caused by autosomal dominant de novo mutations in the COL2A1 gene that lead to a substitution of obligatory glycine residues in the collagen triple helical domain of type II collagen fibrils.