A mild form of pseudoachondroplasia: minimal epi-metaphyseal involvement of long bones.

A problem in diagnosing pseudoachondroplasia (PSACH) is that the pathognomonic changes of vertebral bodies invariably disappear around the age of 10, and an adult case might subsequently be misdiagnosed as MED, Fairbank type, though the latter is less severe than PSACH. We present a Japanese girl (follow-up, 3-10 years of age) whose epi-metaphyseal involvement of long bones was minimal and whose height was +2 S.D. of standard for PSACH in spite of the typical changes of the vertebral bodies. She might not have been diagnosed only as PSACH but also as MED, Fairbank type, after disappearance of the typical vertebral body changes because of the apparent lack of stubby fingers. Since the overlap of PSACH and MED has recently been discussed from the viewpoint of molecular biology, study of the spectrum of clinical features of PSACH is important.