Multiple Endocrine Neoplasia 2A, MEN2A (RET Complete Sequence Analysis, Exons 1-20)
Collect
Collect whole blood in a purple top (EDTA) tube.
Volume Required
5mL
Minimum Required
3mL
Transport
Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday within 24 hours of collection.
Stability
Whole blood can be refrigerated until shipment.
Unacceptable conditions
Heparinized specimens, severely hemolyzed specimens, frozen, clotted or possibly commingled specimens, blood in non-sterile or leaky containers, mislabeled or inappropriately labeled specimens.
Specimen Handling
Do not heat, freeze or centrifuge blood before shipment. Refrigerate sample until shipment.
Days Performed
Mon - Fri 9:00am to 4:00pm
Reported
4-6 weeks
CPT
81406
Disease Information
Clinical Features:
Multiple Endocrine Neoplasia type 2 (MEN 2) is an autosomal dominantly inherited cancer disorder classified in to three subtypes: MEN 2A, MEN 2B and familial medullary thyroid carcinoma (FMTC). All three subtypes carry a high risk for development of medullary carcinoma of the thyroid (MTC). The onset of MTC is in early childhood in MEN 2B and early adulthood in MEN 2A.
MEN2A is characterized by medullary thyroid carcinoma, pheochromocytoma, and parathyroid hyperplasia. MEN2B is characterized by bilateral medullary thyroid carcinoma, pheochromocytoma, diffuse ganglioneuromas of the intestinal tract, mucosal neuromas, and skeletal abnormalities. Symptoms of MEN2B are evident within the first decade of life and progresses rapidly.
Molecular Genetics:
Approximately 95% of families with MEN 2A have a mutation in exon 10 or 11 of the RET proto-oncogene. Approximately 85% of patients with FMTC have an identifiable mutation in exons 10, 11, 13, 14 or 15 of the RET proto-oncogene.
Test Methods:
We offer DNA sequence analysis of exons 1-20 of the RET proto-oncogene. The patient’s gene sequence is then compared to a reference sequence. Sequence variants are classified as mutations, variants of unknown significance or benign variants unrelated to disease. Variants of unknown significance may warrant further studies in the patient and other family members.
Detection Rate:
In 95% of MEN2A cases and 85% of familial medullary thyroid carcinoma patients, the mutation involves one of five cysteine residues in the extracellular domain of the RET proto oncogene. The analytical sensitivity for sequencing is close to 100%.
Related Tests:
Known mutation analysis is available to family members for mutations previously identified by sequence analysis.
Results:
Test results with interpretation will be mailed and/or faxed to the referring physician following completion of the test. Additional reports will be provided as requested.
Utility:
The clinical utility of these assays is in confirming a clinical diagnosis of MEN 2A, facilitate pre-symptomatic testing of at risk relatives, confirm the need for clinical surveillance or surgery in patients positive for a mutation, and to facilitate prenatal diagnosis.
Remarks
Whole blood in EDTA purple top tubes is the preferred sample. High molecular weight genomic DNA, cheek epithelial cells, or other samples containing DNA may be acceptable. Contact the laboratory for specific instructions regarding such samples before sending the sample.
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