• Test Code:
    2045
  • Department:
  • Test Synonyms:
    MUTYH (MYH) full gene sequencingMUTYH-Associated Polyposis (MAP) sequencing Familial Adenomatous Polyposis (FAP) sequencing
  • CPT Code(s):
    81406
Background:

MUTYH-associated polyposis is an autosomal recessive disorder associated with numerous colorectal polyps and the attenuated familial adenomatous polyposis (AFAP) phenotype. Attenuated familial adenomatous polyposis (AFAP) is similar to familial adenomatous polyposis (FAP), but with fewer polyps (generally less than 100), polyps located more proximally in the colon, as well as a later age of onset by approximately 10 years. Depending on the population studied, small germline mutations in APC account for 70-90% of FAP cases and 16% of AFAP cases while larger deletions and duplications of APC account for approximately 15% of FAP/AFAP cases. Biallelic MUTYH mutations are identified in approximately 20% of FAP and 30% of AFAP patients that have no mutations detected in APC.

Reasons for Referral:

  • Identification of inherited genetic defects in MUTYH in patients with FAP/AFAP characteristics or early onset colon cancer.
  • Confirmation of a suspected diagnosis with a positive family history of early onset colon cancer when a familial mutation is known.
  • Predispositional testing for asymptomatic family members with a positive family history of colorectal cancer.

Methodology:

Sequencing can be performed by either method below:

Sanger Sequencing: Sequencing of MUTYH is carried out by amplification of all exons and intron/exon boundaries followed by bi-directional Sanger sequencing. The sensitivity of full gene sequencing is estimated to be approximately 99% for single nucleotide substitutions and small insertions/deletions. All nucleotide changes are analyzed within the context of current databases and literature to predict pathogenicity.

NGS Sequencing: Next generation sequencing will analyze the exons or coding regions of MUTYH using Illumina NextSeq 500 technology.  Samples are prepared using hybridization probes to enrich exonic regions.  Promoter, intronic, etc. regions are not assessed on our assay, but may contain variants that impact gene function.

Specimen Requirements:

Blood: EDTA or ACD (Solution Aor B):

  • Adult: 5mL
  • Child: 5mL
  • Infant: 2-3mL

Saliva: 2 ORAgene Saliva Kit(s) (OGR-500)

Skin Fibroblast: Punch Biopsy, or 2 T-25 confluent flasks

Prenatal:

  • Direct Amniotic Fluid (10-20mL)
  • Direct CVS
  • Cultured Amnio or CVS (2-T25 flasks)

DNA: 1-2µg at a minimum of 50-100ng/µL (DNA must be extracted in a CLIA-certified laboratory or a laboratory meeting equivalent requirements as determined by the CAP and/or CMS)

Notice Regarding Molecular Genetic Testing on CVS or Amniotic Fluid Specimens:

  • Maternal cell rule-out testing will be performed on all prenatal specimens received.Please provide maternal blood in addition to the fetal specimen.Additional charges apply for the maternal cell rule-out test.
  • All genetic testing performed on Direct CVS or Direct Amniotic Fluid specimens will be confirmed on cell cultures prepared by Knight Diagnostic Laboratories.Cell cultures will be prepared from the specimen received.Additional charges apply for confirmatory testing.

For routine testing of blood and saliva (or DNA extracted from them), KDL does NOT accept samples from patients within two (2) weeks of a packed cell/platelet transfusion or within four (4) weeks of a whole blood transfusion.  For extraordinary circumstances, where testing must be performed outside of the above windows, please contact our lab.

A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES.  Please include detailed clinical information, including ethnicity, clinical history, and family history.

Test Performed (Days):

Weekly

Turn Around Time:

14 - 21 days

Shipment Sensitivity Requirements:

  • Package and ship specimen to remain cold, but not frozen. 
  • Ship via overnight express, using the FedEx priority overnight label provided. 
  • Contact Client Services for shipping kits and instructions at (855) 535-1522.

References:

  1. Lefevre M, et al. Implications of MYH in Colorectal Polyposis. Ann Surg 2006; 244: 874-879.
  2. Aretz S, et al. MUTYH-associated polyposis: 70 of 71 patients with biallelic mutations present with an attenuated or atypical phenotype. Int. J.  Cancer 2006; 119: 807-814.
  3. Aretz S, et al. Large submicroscopic genomic APC deletions are a common cause of typical familial adenomatous polyposis. J Med Genet 2005; 42: 185-192.
  4. Aretz S, et al. MUTYH-associated polyposis: 70 of 71 patients with biallelic mutations present with an attenuated or atypical phenotype. Int. J.  Cancer 2006; 119: 807-814.
  5. Giardiello F, et al. AGA Technical Review on Hereditary Colorectal Cancer and Genetic Testing. Gastroenterology 2001; 121: 198-213.
  6. Lefevre M, et al. Implications of MYH in Colorectal Polyposis. Ann Surg 2006; 244: 874-879.
  7. Nielsen M, et al. Germline mutations in APC and MUTYH are responsible for the majority of families with attenuated familial adenomatous polyposis. Clin Genet 2007; 71: 427-433.

Additional Info:

The Knight Cancer Institute at Oregon Health & Science University is a pioneer in the field of precision cancer medicine. The institute's director, Brian Druker, M.D., helped prove it was possible to shut down just the cells that enable cancer to grow. This breakthrough has made once-fatal forms of the disease manageable and transformed how cancer is treated. The OHSU Knight Cancer Institute is the only National Cancer Institute-designated Cancer Center between Sacramento and Seattle – an honor earned only by the nation's top cancer centers. It is headquarters for one of the National Cancer Institute's largest research collaboratives, SWOG, in addition to offering the latest treatments and technologies as well as hundreds of research studies and clinical trials.

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