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Interpretive Handbook

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Test 61491 :
STK11 Gene, Full Gene Analysis

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder characterized by gastrointestinal (GI) hamartomatous polyps and melanotic macules. The GI polyps are most common in the small intestine. Although typically benign, these polyps can cause chronic bleeding and may result in obstruction and intussusception. Pigment changes, typically dark blue spots around the lips, buccal mucosa, and fingers, appear in childhood. Affected individuals are also at an increased risk for a variety of malignancies including colorectal, gastric, breast, thyroid, pancreatic, uterine, and sertoli cell and sex cord tumors. PJS is caused by mutations in the STK11 (formerly LKB1) gene.

Useful For Suggests clinical disorders or settings where the test may be helpful

Confirming a diagnosis of Peutz-Jeghers syndrome

Interpretation Provides information to assist in interpretation of the test results

All detected alterations will be evaluated according to American College of Medical Genetics and Genomics (ACMG) recommendations.(1) Variants will be classified based on known, predicted, or possible pathogenicity, and reported with interpretive comments detailing their potential or known significance.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

A small percentage of individuals who have a diagnosis of Peutz-Jeghers syndrome (PJS) may have a mutation that is not identified by this method (eg, promoter mutations, deep intronic alterations). The absence of a mutation, therefore, does not eliminate the possibility of the diagnosis of PJS. For testing asymptomatic individuals it is important to first document the presence of an STK11 gene mutation in an affected family member.

 

In some cases, DNA alterations of undetermined significance may be identified.

 

Rare polymorphisms exist that could lead to false-negative or false-positive results. If results obtained do not match the clinical findings, additional testing should be considered.

 

A previous bone marrow transplant from an allogenic donor will interfere with testing. Call Mayo Medical Laboratories for instructions for testing patients who have received a bone marrow transplant.

 

Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors in our interpretation of results may occur if information given is inaccurate or incomplete.

 

We strongly recommend that patients undergoing predictive testing receive genetic counseling both prior to testing and after results are available.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Richards CS, Bale S, Bellissimo DB, et al: ACMG recommendations for standards of interpretation and reporting of sequence variations: revisions 2007. Genet Med 2008:10(4):294-300

2. Amos CI, Frazier ML, Wei C, McGarrity TJ: Peutz-Jeghers Syndrome. In GeneReviews [Internet]. Edited by RA Pagon, TD Bird, CR Dolan, et al. University of Washington, Seattle, Updated 2011 Feb 22

3. Beggs AD, Latchford AR, Vasen HF, et al: Peutz-Jeghers syndrome: a systematic review and recommendations for management. Gut 2010 Jul;59(7):975-986

4. Hearle N, Schumacher V, Menko FH, et al: Frequency and spectrum of cancers in the Peutz-Jeghers syndrome. Clin Cancer Res 2006 May 15;12(10):3209-3215


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