Test Catalog

Test ID: TP53Z    
TP53 Gene, Li Fraumeni Syndrome, Full Gene Analysis, Varies

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

Confirmation of suspected clinical diagnosis of Li-Fraumeni syndrome or Li-Fraumeni-like syndrome

 

Identification of familial TP53 mutation to allow for predictive testing in family members

Genetics Test Information Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test evaluates for the presence of germline TP53 mutations associated with Li Fraumeni syndrome. For patients with a history of hematologic malignancy and/or bone marrow transplant, consultation with the laboratory is required prior to submitting a specimen.

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, comparative genomic hybridization array will always be performed at an additional charge.

 

See TP53 Mutation Testing Analysis in Special Instructions.

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

Li-Fraumeni syndrome (LFS) is a rare autosomal dominant hereditary cancer syndrome associated with germline mutations in the TP53 (also p53) gene. LFS is predominantly characterized by sarcoma (osteogenic, chrondrosarcoma, rhabdomyosarcoma), young-onset breast cancer, brain cancer (glioblastoma), hematopoietic malignancies, and adrenocortical carcinoma in affected individuals. LFS is highly penetrant; the risk for developing an invasive cancer is 50% by age 30 and 90% by age 70 with many individuals developing multiple primary cancers. Childhood cancers are also frequently observed and typically include soft-tissue sarcomas, adrenocortical tumors, and brain cancer. Other reported malignancies include melanoma, Wilms tumor, kidney tumors, gonadal germ cell tumor, pancreatic cancer, gastric cancer, choroid plexus cancer, colorectal cancer, prostate cancer, endometrial cancer, esophageal cancer, lung cancer, ovarian cancer, and thyroid cancer.

 

There are published criteria for the use in establishing a clinical diagnosis of classic Li-Fraumeni syndrome and Li-Fraumeni-like (LFL) syndrome that include the above features listed. A larger percentage of families that meet the classic LFS criteria, are predicted to have a detectable mutation within the TP53 gene than families that meet the less strict LFL criteria (Birch's and Eeles' definitions).

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.

Interpretation Provides information to assist in interpretation of the test results

All detected alterations are evaluated according to American College of Medical Genetics recommendations.(1) Variants are 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

Some individuals who have a diagnosis of Li-Fraumeni syndrome or Li-Fraumeni-like syndrome may have a mutation that is not identified by this method (eg, deep intronic mutations, promoter mutations). The absence of a mutation, therefore, does not eliminate the possibility of a diagnosis of Li-Fraumeni syndrome or Li-Fraumeni-like syndrome. For predictive testing of asymptomatic individuals, it is important to first document the presence of a TP53 gene mutation in an affected family member.

 

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

 

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

 

Predictive testing of an asymptomatic child is not recommended.

 

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.

 

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.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Richards S, Aziz N, Bale S, et al: Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med 2015 May;17(5):405-424

2. Lindor NM, McMaster ML, Lindor CJ, et al: Concise handbook of familial cancer susceptibility syndromes - second edition. J Natl Cancer Inst Monogr 2008;(38):1-93

3. Masciari S, Syngal S: The role of p53 in colorectal cancer. In Genetics of Colorectal Cancer. Edited by JD Potter, NM Lindor. New York, Springer, 2009, pp 213-217

4. Schneider K, Zelley K, Nichols KE, et al: Li-Fraumeni Syndrome. In GeneReviews. Edited by RA Pagon, MP Adam, HH Ardinger, et al: University of Washington, Seattle. 1993-2014. 1999 Jan 19 (Updated 2013 Apr 11). Available at www.ncbi.nlm.nih.gov/books/NBK1311/

Special Instructions Library of PDFs including pertinent information and forms related to the test