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DNMT3A Exon 23 Mutational Analysis

Indication

DNMT3A belongs to a group of enzymes called DNA methyltransferases (DNMTs) that catalyze the DNA methylation and thereby regulate gene expression. In humans, these proteins are encoded by genes: DNMT1, DNMT3A, and DNMT3B. DNMT3A and DNMT3B catalyze de novo methylation, which establishes the methylation patterns in early embryo, during development, and during embryogeneis. DNMT3A protein contains an N-terminal and a smaller C-terminal part encoded by the DNMT3A gene located at chromosome 2p23. Somatic mutations in DNMT3A are described in AML cases and are shown to have an overall poor survival outcome and a shortened event-free survival. These mutations are classified amongst two major classes: highly recurrent p.R882 mutations (exon 23), and a second class of all other mutations. MDL has developed high resolution melting (HRM) curve analysis to detect any sequence variants in exon 23 of DNMT3A, which includes the highly recurrent p.R882 mutations. All sequence variants/mutations are further confirmed by bi-directional Sanger sequencing.

Methodology

PCR-based DNA amplification followed by Sanger sequencing.  This assays is also available on a Next Gen Sequencing platform as part of a 53 gene panel, interrogating Exon 23, codons 867-913.

Test Parameters

The assay is designed to detect sequence alterations/mutations in exon 23 of DNMT3A. The lower limit of detection is based on Sanger sequencing and is approximately 20% of mutated cells carrying heterozygous sequence alteration/mutation in the background of cells with wild-type DNA.

Turnaround Time

10 days

Sample Requirements

10 mL peripheral blood, 2-5mL bone marrow aspirate, or 5µg purified DNA. Tissue sections may also be utilized for testing purposes, and testing requires formalin-fixed, paraffin embedded tissue blocks or 4-10 unstained tissue sections on glass slides along with 1 H&E-stained section containing adequate amounts of tumor to be analyzed (see above sensitivity), with areas to be tested clearly indicated on the slides/block. Please provide a copy of the corresponding pathology report.

CPT Codes

81403

Additional charges may apply for tissue extraction.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.


© 2014 The University of Texas MD Anderson Cancer Center