The disorder is an autosomal recessive trait, although there may be other modes of inheritance. Camptomelic dysplasia is in some cases associated with XY sex reversal. The majority of infants born with camptomelic dysplasia appear to be female, but genetic studies show that many are actually male with XY gonadal dysgenesis.
In one third of cases, hydramnios is detected during pregnancy. Stillbirth is common, and many liveborn infants die in the neonatal period or live for only several months; many develop severe respiratory distress, in part related to hypoplasia and other abnormalities of the tracheobronchial tree.
Although prognosis is guarded during the first year of life, with medical intervention, more and more children with camptomelic dysplasia survive into young adulthood.
Clinical Manifestations. At birth, infants have a low-normal weight, a relatively large and long (dolichocephalic) head, and disproportionate short length, primarily in the lower limbs.
The prominent forehead, rather flat face, depressed nasal bridge, long philtrum, small mouth, small jaw (micrognathia), and occasionally wide-set eyes and low-set ears produce a characteristic facies. Cleft palate occurs in most patients.
The arms are normal or only slightly shortened and bowed. The tibias are often bent, or boomerang shaped, with a cutaneous dimple over the apex of the bend. The femurs tend to be anterolaterally bowed, and clubfoot is common. The thorax is often small, narrow, and bell shaped. Progressive scoliosis is common. Hypotonia is an additional feature.
Stridor and laryngotracheomalacia are major hazards in infancy, leading to long-term episodes of apnea, pulmonary aspiration, cyanosis, respiratory failure, seizures, and feeding difficulties. Tracheostomy and ventilatory assistance are frequently necessary for long periods of time. Congenital heart disease is found in nearly 25% of patients and hydronephrosis in 38%. Hemorrhagic phenomena in the central nervous system, hydrocephalus, and absence or hypoplasia of olfactory bulbs or tracts occur in 20% of patients.
Radiographic Findings. The typical findings reflect the three phenotypes: (I) classic (long-limb) type, characterized by bowed long bones with normal caliber and moderate shortening; (II) short-limb type, marked by severely shortened and bowed long bones and essentially normal neurocranium; and (III) short-limb type, associated with premature closure of cranial sutures (craniosynostosis).
Common to all three types are a large skullcap (calvaria) in relation to facial size; a small, bell-shaped thorax with thin, wavy ribs; slender clavicles; and small scapulas. The femurs and tibias show variable degrees of bowing, and the fibulas are hypoplastic. Congenital dislocation of the hips is common. The pelvis is narrow with dysplastic pubic rami, and the ischia appear vertical or even divergent. Scoliosis or kyphoscoliosis occurs frequently.
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