Test Code STK1Z Peutz-Jeghers Syndrome, STK11, Full Gene Analysis, Varies

Ordering Guidance

For a comprehensive hereditary cancer panel that includes the STK11 gene, consider 1 of the following tests:

-CRCGP / Hereditary Gastrointestinal Cancer Panel, Varies

-BRGYP / Hereditary Breast/Gynecologic Cancer Panel, Varies

Testing for the STK11 gene as part of a customized panel is available. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies.

Targeted testing for familial variants (also called site-specific or known mutations testing) is available for the genes on this panel. See FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.

Shipping Instructions

Specimen preferred to arrive within 96 hours of collection.

Specimen Required

Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated

Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519)

3. If not ordering electronically, complete, print, and send a Oncology Test Request (T729) with the specimen.

Secondary ID

614588

Useful For

Evaluating patients with a personal or family history suggestive of Peutz-Jeghers syndrome (PJS)

Establishing a diagnosis of PJS allowing for targeted cancer surveillance based on associated risks

Identifying variants within genes known to be associated with increased risk for PJS allowing for predictive testing of at-risk family members

Special Instructions

Method Name

Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing.

Reporting Name

STK11 Full Gene Analysis

Specimen Type

Varies

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type	Temperature	Time	Special Container
Varies	Varies

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Germline variants in the STK11 gene are associated with Peutz-Jeghers syndrome (PJS), an autosomal dominant hereditary cancer syndrome.(1-4) PJS is characterized by many manifestations beginning in childhood, including gastrointestinal hamartomatous polyps, pigmentation changes (called melanocytic macules) around the mouth, eyes, buccal mucosa, perianal area, hands, and feet, and an increased lifetime risk for developing a variety of cancers.(1-4) The highest cancer risks for PJS are in breast, colorectal, gastric, pancreas, lung, gonads, cervix, and uterus.(1-4) Approximately 10% to 20% of individuals with PJS have no family history and are thought to have genetic variants that occurred de novo.(1,5)

The National Comprehensive Cancer Network and the American College of Gastroenterology provide recommendations regarding the medical management of children and adults with PJS.(5,6)

Reference Values

An interpretive report will be provided.

Interpretation

All detected variants are evaluated according to American College of Medical Genetics and Genomics recommendations.(7) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.

Method Description

Next-generation sequencing (NGS) and/or Sanger sequencing are performed to test for the presence of variants in coding regions and intron/exon boundaries of the STK11 gene, as well as some other regions that have known disease-causing variants. The human genome reference GRCh37/hg19 build was used for sequence read alignment. At least 99% of the bases are covered at a read depth over 30X. Sensitivity is estimated at above 99% for single nucleotide variants, above 94% for deletion/insertions (delins) less than 40 base pairs (bp), above 95% for deletions up to 75 bp and insertions up to 47 bp. NGS and/or a polymerase chain reaction-based quantitative method is performed to test for the presence of deletions and duplications in the STK11 gene.

There may be regions of the gene that cannot be effectively evaluated by sequencing or deletion and duplication analysis as a result of technical limitations of the assay, including regions of homology, high guanine-cytosine (GC) content, and repetitive sequences.(Unpublished Mayo method)

The reference transcript for STK11 gene is NM_000455.5. Reference transcript numbers may be updated due to transcript re-versioning. Always refer to the final patient report for gene transcript information referenced at the time of testing.

Confirmation of select reportable variants may be performed by alternate methodologies based on internal laboratory criteria.

Day(s) Performed