Acampomelic campomelic dysplasia: further radiographic variations

SOX9 dimerization domain mutation mimicking type 2 collagen disorder phenotype

The classification of bone dysplasia has relied on a clinical/radiographic interpretation and the identification of specific genetic alterations. The clinical presentation of the SOX9 mutation and type 2 collagen disorders overlap with the Pierre-Robin sequence and talipes equinovarus, but the former is often accompanied by the bent long bones. In its milder form, the SOX9 mutation is not necessarily associated with the bent long bones. Here, we report a patient with the Pierre-Robin sequence and talipes equinovarus who did not exhibit either bent long bones or scapular hypoplasia; thus, this patient was instead classified as having a type 2 collagen disorder. Despite this phenotypic presentation, the proposita was found to have a de novo SOX9 mutation. The peculiar location of the mutation within the dimerization domain might account for the relatively mild phenotypic effect of the SOX9 mutation to a degree that is compatible with a clinical diagnosis of type 2 collagen disorder, except for a developmental delay. We concluded that mutations in SOX9 can mimic a type 2 collagen disorder-like phenotype.

Orthopaedic manifestations of campomelic dysplasia

Campomelic dysplasia is a rare form of congenital dwarfism associated with potentially fatal respiratory insufficiency. There are several types of campomelic dysplasia; however, it is characterized by the presence of anteriorly bowed tibias with cutaneous dimpling, anterolaterally bowed femurs, thoracic kyphoscoliosis, hypoplastic scapulas, and absence or delayed ossification of thoracic pedicles. With improving treatment of respiratory insufficiency, the survival rate of affected infants has increased, thereby necessitating treatment of the musculoskeletal malformations to prevent additional morbidity. In an attempt to increase awareness of the presentation of infants with campomelic dysplasia and to emphasize the difficulties of treating associated developmental dislocation of the hip early, the current authors report the case of a 2-year-old girl with campomelic dysplasia who was treated for dislocation of the right hip. The postoperative course of this child was complicated seriously by several apneic episodes secondary to tracheobronchial malacia for which she required admission to the pediatric intensive care unit.