Campomelic dysplasia: A severe birth defect that affects the formation of the bones, genital organs, and facial features. The name "campomelic" comes from the Greek words meaning "bent limb." Physical features of the condition typically include bowing of the long bones of the legs and sometimes the arms, characteristic dimpling of the skin over the abnormal bones, shortened legs, underdeveloped shoulder blades, dislocated hips, abnormally rotated feet (clubfeet), and an abnormal number of ribs. Distinctive facial features include a small chin, prominent eyes, and a flattened face. Maldevelopment of the airway in affected people can cause difficulty breathing.
Abnormalities of the genitalia may result in ambiguous genitalia (that do not appear clearly male or female), and the internal sex organs may not correspond with the appearance of the external genitalia. Pierre-Robin sequence is a cluster of abnormalities that often occur in people with campomelic dysplasia. It includes an opening in the roof of the mouth (a cleft palate), a tongue that is placed further back than normal (glossoptosis), and a small lower jaw (micrognathia).
Campomelic dysplasia is inherited in an autosomal dominant pattern, and estimates of its prevalence range from 1 in 40,000 to 200,000 births. It is caused by mutations in a gene known as SOX9. Only a few people with campomelic dysplasia survive past infancy.