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GNAS Mutational Analysis

GNAS Mutational Analysis

Indication:  

The GNAS gene is mutated, over-expressed and/or amplified in number of diseases including McCune Albright syndrome, thyroid and parathytoid tumors, adrenocortical lesions, pituitary tumors, renal tumors and, rare cases of tumors arising from autonomic ganglia, large intestine, lung and testis. GNAS mutation hotspots are codon 201 in exon 8 and/or codon 227 in exon 9.

Clinically, GNAS mutations can provide evidence of an oncogenic molecular abnormality in appropriate clinicopathologic settings. Also, GNAS mutation in pituitary neoplasms is implicated in increased octreotide (somatostatin agonist) sensitivity in some studies. Understanding the GNAS mutational status at the individual patient level will enable targeted drug testing and further facilitate the advancement of personalized treatment.

Methodology:  

This test is performed by PCR-based Sanger sequencing of DNA to examine the mutation status of exons 8 and 9 of GNAS.

Test Parameters:  

This assay will detect mutations present in exons 8 and 9 of GNAS. The sensitivity of the Sanger sequencing assay is 20% of variant sequence in the background of wild-type sequence.

Turnaround Time:

7-10 days

Sample Requirements:

• 10 ug of purified DNA, sent on dry ice

or

• Four to six unstained recut slides of formalin-fixed, paraffin embedded tissue containing adequate amounts of tumor to be analyzed (See Sensitivity.)
The area of tumor to be analyzed should be indicated by circling the area on the bottom side of the slide or in a separate H&E-stained guide section.
Please provide a copy of the corresponding pathology report.

CPT Codes:

81479

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