EXON-SCANNING MUTATION ANALYSIS OF THE ATM GENE IN PATIENTS WITH ATAXIA-TELANGIECTASIA

Using a polymerase chain reaction single strand conformation polymorph ism (PCR-SSCP) assay, which amplifies individually all coding exons of the ATM gene deficient ataxia-telangiectasia (A-T), we have analyzed 10 patients with A-T for ATM mutations. Mutation were detected in 9 pa tients. We describe the first ATM mutation in the splice junction foun d in the 5' splice site of intron 17, leading to exon skipping. Howeve r, most mutations were small deletions or insertions resulting in prem ature termination of the translation product. The development of DNA-b ased methods for detection of unknown mutations and further characteri zation of ATM mutation pattern will facilitate identification of A-T c arriers and assessment of their cancer risk.