Non-rhizomelic and rhizomelic chondrodysplasia punctata within a single complementation group

Several patients have been described recently who suffer from a non-rhizomelic type of chondrodysplasia punctata (CDP), but who show all the biochemical abnormalities characteristic of the rhizomelic form of chondrodysplasia punctata (RCDP), a peroxisomal disorder. We have used protease protection experiments and microinjection of repotter-protein-encoding expression plasmids to show that peroxisomal thiolase fails to be imported into peroxisomes in cells from non-rhizomelic CDP patients, as has already been found in cells from classical RCDP patients. Furthermore, complementation analysis after somatic cell fusion indicates that the non-rhizomelic CDP patients are impaired in the same gene as classical RCDP patients. We conclude that defects in a single gene can give rise to both clinical phenotypes.