Achondrogenesis

Achondrogenesis is a group of severe genetic disorders of cartilage and bone development. Most affected infants die before birth or soon after, often from respiratory failure. All forms share short arms and legs, a narrow chest and underdeveloped lungs. Three main types are described: type 1A, linked to the TRIP11 gene, with easily broken ribs and very little ossification of the skull and spine; type 1B, linked to SLC26A2, with short fingers and toes, clubfeet and sometimes hernias; and type 2, linked to COL2A1, with reduced ossification of the spine and pelvis and facial features such as a prominent forehead, a small chin and sometimes a cleft palate. Types 1A and 1B are autosomal recessive, while type 2 is autosomal dominant, usually from a new variant. It occurs in roughly 1 in 40,000 to 60,000 newborns.