Germline mutations in the colorectal cancer susceptibility genes may consist of complex genomic rearrangements including single and multi-exonic deletions and/or duplications that are challenging to detect by traditional PCR-based methodologies. Deletions and duplications involving single or multiple exons have been described in approximately 8%-12% of individuals with an APC -associated polyposis condition [1,2] and genomic rearrangements in the MSH2 and MLH1 genes represent frequent mutational events in a significant proportion of families with HNPCC [3,4]. A custom-designed microarray is available at the Baylor DNA Diagnostic Laboratory for high resolution copy-number analysis of the APC , MLH1 , MSH2 , MSH6 and MUTYH genes. This array includes approximately 4500 oligonucleotide probes distributed across both exonic and intronic sequences of the above genes and allows the detection of intragenic deletions and duplications at the level of a single exon. Reasons For Referral:
Testing Methodology:DNA isolated from peripheral blood is hybridized to a high density oligonucleotide array to detect intragenic deletions and duplications. Multiplex Ligation-dependent Probe Amplification (MLPA) and Real Time quantitative PCR assays may be conducted to confirm findings. Limitations of Testing:These methodologies will not detect point mutations, inversions, balanced translocations or low level mosaicism. Smaller rearrangements within an exon may not be detected. For the MUTYH gene, deletions/duplication involving less than 2 exons may not be detected. Specimen Requirements:Blood: EDTA (purple-top) tubes: Adults: 14 cc; Child/Infant: 6 cc Turnaround Time:Index: 4 weeks CPT Codes and Prices:For information on fees or CPT Codes for this test, please contact our Billing Office at 713-798-3295. Shipping InformationForms:References:
Test Codes:Index: 6700 |