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Li-Fraumeni Syndrome (P53)

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LI-FRAUMENI SYNDROME (P53)

Gene Symbol: TP53

Chromosomal Locus: 17p13.1
 
Protein: p53 tumor suppressor
 
Pseudonyms: Li-Fraumeni Syndrome (LFS), TP53, SBLA Syndrome
 
TURNAROUND TIME: 15 days
   
AMA 2012 CPT code: 81405
 
TESTING METHODOLOGY: Polymerase chain reaction (PCR) and DNA sequencing of the coding region (exons 2-11).
 
SPECIMEN REQUIREMENTS:
  • Collect: Prefer two 5ml whole blood EDTA (lavender top) tube.
  • Min. Collection: 0.7 ml whole blood EDTA.
  • Transport: blood EDTA at Room Temp shipped regular next day air (No Saturday delivery; store specimen at 4°C and ship Monday).
  • Stability: Ambient: up to 7 days; Refrigerated: 2 weeks. Frozen: unacceptable
  • Unacceptable Conditions: Serum. Frozen or severely hemolyzed blood. Clotted blood.
  • Prenatal testing: Direct: 5ml direct unspun amniotic fluid or 15mg CVS tissue with a backup flask growing. Culture: confluent T25 flask. Maternal blood sample is required for maternal cell contamination studies.
A Molecular Genetics Laboratory Test Requisition must accompany the specimen. Contact the Molecular Laboratory at 918-502-1721 to obtain further information.
Note: Counseling and informed consent are recommended for genetic testing. A consent form is available as a resource but not required.
 
INTERPRETATIVE DATA:
 
Incidence: Undetermined, rare
 
Inheritance: Autosomal Dominant Inheritance
 
Disease Characteristics: Li-Fraumeni syndrome is caused by inherited mutations in the p53 gene. P53 mutations are associated with soft tissue sarcoma, osteosarcoma, breast cancer, brain tumors, adrenocortical carcinoma (ACC), and other types of cancer.
 
Molecular Genetic Mechanism: Li-Fraumeni syndrome is caused by mutations throughout the p53 gene.
 
Clinical Sensitivity: Sequencing of the coding exons detects 95% of mutations. Mutations are found in about 70% of patients with Li-Fraumeni Syndrome, and 8-22% of patients with Li-Fraumeni-like syndrome.
 
Analytical Sensitivity: 99%
 
Test Limitations: This test would not detect deletions of the entire gene and mutations not within the coding regions of the gene. Rare diagnostic errors can occur due to primer / probe site mutations or rare polymorphisms.
 
INDICATIONS FOR USE:
  • Any person with a diagnosis of Li-Fraumeni Syndrome or Li-Fraumeni-like Syndrome should be tested.
  • Individuals who have a breast tumor under age of 30 and do not have a BRCA1 or BRCA2 gene mutation.
  • Individuals who have a strong family history of cancer; particularly families multiple tumor types.
  • Precocious puberty due to endocrine tumors.
  • Any person with a diagnosis of adrenocortical carcinoma or a choroid plexus carcinoma regardless of family history.
ADDITIONAL RESOURCES:
OMIM - Li-Fraumeni Syndrome: www.omim.org/entry/151623