Campomelic dysplasia

Campomelic dysplasia (also known as campomelic syndrome or camptomelic dysplasia) is a rare, severe skeletal disorder caused by mutations in the SOX9 gene located on chromosome 17q24. The term 'campomelic' derives from the Greek words for 'bent limb,' reflecting one of the hallmark features of this condition — bowing of the long bones, particularly the tibiae and femora. The disorder affects multiple body systems including the skeletal system, respiratory system, and reproductive system. Key skeletal features include shortening and bowing of the lower limbs, hypoplastic scapulae, eleven pairs of ribs, a bell-shaped narrow thorax, cervical spine abnormalities, and talipes equinovarus (clubfoot). Craniofacial features include a flat face, micrognathia (small jaw), cleft palate, and a large head with a prominent forehead. A distinctive and clinically significant feature is that approximately two-thirds of 46,XY individuals with campomelic dysplasia exhibit sex reversal, presenting with female or ambiguous external genitalia due to the critical role of SOX9 in male sex determination. The condition is typically lethal in the neonatal period, with the majority of affected infants dying within the first weeks to months of life, primarily due to respiratory insufficiency caused by a small, poorly developed thoracic cage and tracheobronchomalacia (softening of the airway cartilage). However, long-term survival has been reported in a minority of cases, and these individuals may develop additional features including progressive kyphoscoliosis, short stature, hearing loss, and intellectual disability. There is no cure for campomelic dysplasia. Treatment is supportive and multidisciplinary, focusing on respiratory management (which may include tracheostomy and ventilatory support), orthopedic interventions for skeletal deformities, and appropriate management of sex development differences. Genetic counseling is important for affected families, as most cases arise from de novo (new) mutations, though rare instances of autosomal dominant inheritance from a mildly affected parent have been documented.

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