Lee said that the new mechanism of brittle bone disease will have important diagnostic implications. "In child abuse cases, a frequent question is whether the children have brittle bone disease that would cause frequent bone fractures," said Lee. "Up until now, the only known genetic cause of brittle bone disease has been structural mutations in type I collagen. Now, we have explained a percentage of cases of brittle bone disease perhaps as high as fifteen percent that had all the biochemical hallmarks of the disorder but did not have type I collagen mutations. So this adds a new dimension in terms of DNA testing; clinical geneticists and pediatricians will have a new genetic test to determine whether children have this form of brittle bone disease."

The finding "opens up a whole new field in bone biology, because this has been an unappreciated mechanism of collagen modification," said Lee. Since prolyl 3-hydroxylation occurs in collagen throughout the body including the heart, blood vessels and kidneys defects in this process affecting these other tissues could be the cause of as-yet-undescribed connective tissue diseases, he said.

In further studies, Lee and his colleagues are exploring the role of prolyl 3-hydroxylation in such disorders. Also, they are using the new findings to understand the role of the process in collagen formation.

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Contact: Jennifer Michalowski
michalow@hhmi.org
301-215-8576
Howard Hughes Medical Institute
19-Oct-2006