Molecular Cytogenetics DNA copy number assessment by the use of high-density SNP GeneChips provides genomic copy number information with far greater resolution than conventional cytogenetic analysis. The combined capability of Affymetrix SNP Genechips and different softwares (ArrayAssist Copy Number, Exemplar, CNAT) has the potential to improve the status of genetic diagnostics by increasing the tools available to cytogenetics for the definition of small genomic changes. The Microarray Facility offers the complete diagnostic from DNA isolation to data analysis and diagnostic reporting with Affymetrix 500K Human Mapping Arrays.