Cancer and DNA processing disorders.

Defects in cloned DNA repair genes are now associated with particular human disorders in which an important feature is a predisposition to cancer. Recently some repair genes have been implicated in other aspects of DNA metabolism such as transcription initiation. In addition mutations in a single gene can give rise to phenotypes recognised clinically as different disorders. These newly appreciated complexities, amongst others, will eventually help us to understand the development of the complete clinical phenotype in a range of 'DNA processing disorders'.