Detail of Las Meninas by Diego Velázquez (1656), showing Maribarbola and Nicolasito Pertusato (right),<unk> ondroplastic dwarfs in the entourage of Infanta Margarita<unk>  can be detected before birth by prenatal ultrasound. A DNA test can be performed before birth to detect homozygosity, wherein two copies of the mutant gene are inherited, a lethal condition leading to stillbirths. Clinical features include megalocephaly, short limbs, prominent forehead, thoracolumbar kyphosis and mid-face hypoplasia. Complications like dental malocclusion, hydrocephalus and repeated otitis media can be observed. The risk of death in infancy is increased due to the likelihood of compression of the spinal cord with or without upper airway obstruction. Radiologic findings A skeletal survey is useful to confirm the diagnosis of<unk> . The skull is large, with a narrow foramen magnum, and relatively small skull base. The vertebral bodies are short and flattened with relatively large intervertebral disk height, and there is congenitally narrowed spinal canal. The iliac wings are small and squared, with a narrow sciatic notch and horizontal acetabular roof. The tubular bones are short and thick with metaphyseal cupping and flaring and irregular growth plates. Fibular overgrowth is present. The hand is broad with short metacarpals and phalanges, and a trident configuration. The ribs are short with cupped anterior ends. If the radiographic features are not classic, a search for a different diagnosis should be entertained. Because of the extremely deformed bone structure, people with<unk>  are often "double jointed". The diagnosis can be made by fetal ultrasound by progressive discordance between the short femur length and biparietal diameter by age. The trident hand configuration can be seen if the fingers are fully extended. Another distinct characteristic of the syndrome is thoracolumbar gibbus in infancy.
Achondroplasia
Pseudoachondroplasia
Thanatophoric dysplasia
Hypochondroplasia
Cartilage–hair hypoplasia
Metaphyseal dysplasia
Rachischisis
Cranioschisis