Kyphomelic dysplasias

Kyphomelic dysplasias (also known as "pseudocampomelia") is thought to be a heterogeneous class of "bent bone" skeletal dysplasias. Entities included in a differential for the class are:

• congenital bowing of the long bones
• cartilage-hair hypoplasia (CHH; metaphyseal dysplasia, McKusick type)
• Schwartz-Jampel syndrome
• Antley-Bixler syndrome (short-limbed campomelic syndrome, craniosynostotic form)
• Cummings syndrome

Clinical presentation

There are multiple skeletal anomalies associated with this class of dysplasias, and common manifestations are:

• severe rhizomelic limb shortening
• bowed extremities ("campomelia")
• skin dimples over bowed extremities

Other described anomalies include micrognathia with midface hypoplasia, narrow chest, and facial hemangiomas.

Pathology

Many in the class are thought to be autosomal recessive, but some may be X-linked.

Radiographic features

Antenatal ultrasound

• short, bowed femurs
• short long bones
• small chest with short ribs

Plain radiograph

• short, bowed femurs with metaphyseal flare and irregularity
• eleven ribs, moderately short

Flared and irregular metaphyses of multiple long bones are also associated with these dysplasias, as well as mild platyspondyly and camptodactyly.

Differential diagnosis

Campomelic dysplasia is the main differential consideration, and cases of both dysplasias have sometimes been misattributed to each other .

Stuve-Wiedemann dysplasia is currently thought to be separate from both campomelic dysplasia and the kyphomelic dysplasias.

Osteogenesis imperfecta and congenital hypophosphatasia may also be considered in the differential.