This is a genetic condition that affects the skeletal development, reproductive system and other parts of the body. The individuals affected with campomelic dysplasia present bowing of the legs and sometimes, the bowing of the arms are also apparent. Generally, the abnormalities are evident in the ultrasound before the birth of the infant. However, when other features of this condition are presented but don’t exhibit the bowed limbs, it is termed as acampomelic campomelic dysplasia. The prevalence of this condition is not exactly known, however, it is estimated to affect 1 in 40,000 to 200,000 individuals.
Causes
This condition is inherited in an autosomal dominant manner meaning one copy of the defective gene in each cell can cause this disorder. However, most cases are caused by the new mutation in or near the gene SOX9 which develops in individuals with no history of its presence in the family. Among the healthy individuals, the SOX9 gene delivers the information to produce a protein essential in the development of several tissues and organs during the embryo stage. When this genetic defect is identified to be the cause, the SOX9 protein is either impaired in its function or absent. When this condition is caused by the chromosomal abnormalities near the SOX9 gene, the symptoms associated with this condition may be milder. The SOX9 protein also promotes the activities of other genes particular that are essential for the skeletal and the development of reproductive organs. However, all these changes prevent the SOX9 protein from effectively controlling the genes thus affecting the normal development of the skeletal, reproductive system and other parts of the body.
Symptoms
This skeletal condition presents the bowing of the legs and sometimes also the arms. They may have short legs, underdeveloped shoulder blades, 11 pairs of ribs instead of the normal 12, dislocated hips and clubfeet. The skull of these cases may be large, long or narrow and the facial abnormalities feature the high forehead, cleft palate and small chin. The infants of this disorder may regurgitate their feed via the nose and experience respiratory distress resulting from the underdeveloped rib cage. The laryngotracheomalacia is the condition where the voice box known as the larynx and the windpipe called the trachea are soft causing problems with the airways and breathing difficulties. Several of the infants die as the result of this complication. The abnormal development of the sex organs is another condition associated with this disorder where the individual’s genitalia appear to be ambiguous when the cases detected with the male chromosome (XY) are presented with female genitalia.
Diagnosis
In the case of high-risk pregnancy, particularly when one of the parents has the condition, the diagnosis of CD can be done with DNA analysis from the fetus. When the infant is born, the diagnosis is based on the physical examination in identifying the features associated with this condition. This may be evident in the X-ray findings. In some cases, the genetic testing can be confirmed by the presence of defective gene SOX9.
Treatment
The treatment is based on treating the complications and the symptoms associated with this condition and in enabling the children to adapt socially and physically. The cleft palate may require a surgery consisting of a craniofacial team, the clubfeet and hip dislocation requires the orthopedic surgeons. The spinal deformities must be monitored and in some cases, a surgery may be required. In the case of abnormal sex organs, the chromosome makeup is assessed and the testes or the ovaries are accordingly removed.
References
http://www.nemours.org/service/medical/skeletal-dysplasia/campomelic.html?tab=about
https://rarediseases.org/rare-diseases/campomelic-syndrome/
https://ghr.nlm.nih.gov/condition/campomelic-dysplasia#inheritance