Multiple Endocrine Neoplasia Type 2: RET Sequencing

Test Identifier Information

Exons 8-11 and 13-16 of the RET gene are amplified using PCR and analysed by DNA sequencing.

Multiple endocrine neoplasia type 2 (MEN2) is classified into three subtypes: MEN2A, FMTC (familial medullary thyroid carcinoma) and MEN2B. All three subtypes carry a high risk for development of medullary carcinoma of the thyroid (MTC); MEN2A and MEN2B carry an increased risk for pheochromocytoma; MEN2A carries an increased risk for parathyroid adenoma or hyperplasia. Additional features in MEN2B include mucosal neuromas of the lips and tongue, distinctive faces with enlarged lips, ganglioneuromatosis of the gastrointestinal tract and an asthenic "Marfanoid" body habitus. The onset of MTC is typically in early childhood in MEN2B, early adulthood in MEN2A, and middle age in FMTC. RET is the only gene known to be associated with MEN type 2. All MEN2 subtypes are inherited in an autosomal dominant manner. Molecular genetic testing of the RET gene identifies disease-causing mutations in 95% of individuals with MEN2A and MEN2B and in about 88% of families with FMTC.

Specimen Collection

A minimum of 0.5 mL EDTA (purple top) blood (paediatric) or 5.0 mL EDTA blood (adults).

CHLabs Laboratory

Automated bidirectional DNA sequencing has an analytical sensitivity and specificity of >99%. Note that the lower limit of variant detection of sequencing analysis is ~10%, this is important to consider in the case of mosaicism, mitochondrial, and somatic variation that is not expected to be present at 50% or 100%.  This analysis will not detect variants located within intronic regions, except at the intron-exon boundaries.

1. This test requires nucleated cells. Please do not centrifuge or freeze blood samples.
2. Genomic DNA must be extracted from the specimen prior to testing. This incurs an additional charge (see GDNA). Laboratories may prefer to submit DNA for testing. Please provide a minimum of 5 micrograms of DNA at 20 nanograms/microlitre.