Denouement and Discussion
Pseudoachondroplasia (Pseudoachondroplastic Spondyloepiphyseal Dysplasia)
Pseudoachondroplasia is probably the second most common chondrodystrophy next to true achondroplasia. Individuals with pseudoachondroplasia resemble achondroplastic dwarfs in having long trunks and short limbs, hence the name pseudoachondroplasia. However, in contrast to classical achondroplasia, they have normal craniofacies and are not recognizable at birth. Instead of the clearly defined roentgenographic changes present at birth in achondroplasia, vertebral and epiphyseal abnormalities evolve with time. Patients with pseudoachondroplasia are usually considered normal until 18 months to 2 years of age when they are either late to walk or have a waddling gait. They have short limbs with limitation of extension of the elbows, contractures of the hips and knees occasionally, and hyperextensibility of many other joints. This loose-jointedness increases with age, and the hands are usually held in an ulnar position. The legs are frequently bowed, but knockknee also occurs. Mild to moderate
Gellis SS, Feingold M, Hall JG. Picture of the Month. Am J Dis Child. 1974;128(6):833–834. doi:10.1001/archpedi.1974.02110310081015
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