Spontaneous and X-ray-induced chromosomal aberrations in Werner syndrome cells detected by FISH using chromosome-specific painting probes

Werner syndrome (WS) is a rare autosomal disorder characterized by prematur e aging exhibiting chromosome instability and predisposition to cancer. Cel ls derived from WS patients show a variety of constitutionally stable chrom osomal aberrations as detected by conventional chromosome banding technique s. We have employed the fluorescence in situ hybridization (FISH) technique using painting probes for 12 different chromosomes to detect stable chromo some exchanges in three WS cell lines and three control cell lines. WS cell lines showed increased frequencies of both stable and unstable chromosome aberrations detected by FISH and Giemsa staining, respectively. One WS lymp hoblastoid cell line (KO375) had a 5/12 translocation in all the cells and similar to 60% of the cells had an additional translocated chromosome 12. A high frequency of aneuploid cells was found in all the WS cell lines studi ed. Though WS cells are known to be chromosomally unstable, unlike other ch romosome instability syndromes they are not sensitive to mutagenic agents. We studied the frequencies of X-ray-induced chromosomal aberrations in two WS cell lines and found an similar to 60% increase in the frequencies of fr agments and no consistent increase in the frequencies of exchanges.