Achondrogenesis type 2 (ACG2), a form of achondrogenesis, is a very rare and lethal skeletal dysplasia and part of the spectrum of type 2 collagen-related bone disorders, characterizedby severe micromelia, short neck with large head, small thorax, protuberant abdomen, underdeveloped lungs, distinctive facial features such as a prominent forehead, a small chin, a cleft palate (in some) and distinctive histological features of the cartilage. The disease is MONDO_0008702 (achondrogenesis type II). Also known as: achondrogenesis, Langer-Saldino type, achondrogenesis, type II or hypochondrogenesis.