FBN1 (Marfan Syndrome) Full Gene Sequencing

CPT: 81408
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Test Details

Test Includes

This test covers all coding nucleotides of the FBN1 gene plus at least two and typically 10 flanking intronic nucleotides upstream and downstream of each coding exon, covering the conserved donor and acceptor splice sites, as well as typically 10 flanking nucleotides in the 5′ and 3′ UTR.

Use

Confirm a clinical diagnosis of MFS; identify presymptomatic family members, guiding prophylactic measures

Limitations

This analysis does not rule out germline mosaicism, the presence of large chromosomal aberrations (including deletions, insertions, and rearrangments), mutations in regions or genes not included in this test, and possible inter/intragenic interactions between sequence variants. False-positive or false-negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, mislabeled specimens, or erroneous representation of family relationships.

This test was developed, and its performance characteristics determined, by LabCorp. It has not been cleared or approved by the US Food and Drug Administration (FDA).

Methodology

Mutation analysis is performed using the Agilent Sure Select XT® enrichment method and the Illumina® next-generation sequencing platform. Regions of interest include all exons and splice junctions for each gene. Sequencing reads are aligned with the hg19 build of the human genome reference sequence. Analytical sensitivity is based on the depth of coverage across regions of interest and is provided separately for each gene. Greater than 98% of target bases are synonymous variants not previously recorded at greater than or equal to 20x coverage. Sanger sequencing is used to confirm mutation identity and analyze regions with low coverage. Variants are reported using numbering and nomenclature recommended by the Human Genome Variation Society (HGVS: http://hgvs.org/). Variants known to be benign and synonymous variants not previously recorded in our internal variant databases are not reported.

Additional Information

Marfan syndrome (MFS) is a dominantly inherited systemic connective tissue disorder characterized by multiple variable abnormalities of the skeletal, ocular, cardiovascular, pulmonary, skin, and nervous systems. Morbidity and mortality are mostly due to aortic dilation, which can lead to aortic rupture and/or dissection. At least 90% of MFS are associated with mutations in FBN1. Genetic testing can confirm a clinical diagnosis of MFS, help to establish a diagnosis in patients with only partially fulfilled clinical criteria, and allow for accurate identification of presymptomatic mutation carriers within affected families.

Specimen Requirements

Specimen

Whole blood

Volume

10 mL whole blood or 30 mL if ordering multiple tests

Minimum Volume

3 mL

Container

Yellow-top (ACD) tube or Lavender-top (EDTA) tube

Storage Instructions

Maintain specimen at room temperature. Specimen can be stored for brief periods at 4°C.

Causes for Rejection

Frozen specimen; container broken or leaking; container not labeled or label not legible; improper anticoagulant

Clinical Information

Special Instructions

For all tests, specimens must be accompanied by a completed consent form. See sample physician office consent form: Consent for Genetic Testing in Related Documents. In cases in which a known mutation can be documented, the physician may prefer to order Test 451382, Mutation-specific Sequencing, Whole Blood (link in Related Information). Please call customer service at 866-647-0735 before submitting specimens for family testing (ie, known mutations).

References

Comeglio P, Johnson P, Arno G, et al. The importance of mutation detection in Marfan Syndrome and Marfan-related disorders: Report of 193 FBN1 mutations. Human Mutat. 2007 Sep;28(9):928.17657824
Dietz HC. Marfan Syndrome. Gene Reviews. Available at: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=marfan. Accessed February 06, 2010.20301510
Faivre L, Collod-Beroud G, Child A, et al. Contribution of molecular analyses in diagnosing Marfan Syndrome and type I fibrillinopathies: An International study of 1009 probands. J Med Genet. 2008 Jun;45(6):384-390.18310266

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
452028 FBN1: Marfan Syndrome 452029 Specimen Type 31208-2
452028 FBN1: Marfan Syndrome 452030 Results: 77114-7
452028 FBN1: Marfan Syndrome 452031 Key Findings 53037-8
452028 FBN1: Marfan Syndrome 452032 Additional Information 49549-9
452028 FBN1: Marfan Syndrome 452033 Gene Information 51968-6
452028 FBN1: Marfan Syndrome 452034 Tech Spec Results 51958-7
452028 FBN1: Marfan Syndrome 452035 Seq Variants Detected 69548-6
452028 FBN1: Marfan Syndrome 452036 Disclaimer 62364-5
452028 FBN1: Marfan Syndrome 452037 Director Review: 48672-0
452028 FBN1: Marfan Syndrome 452038 PDF 51969-4

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CPT Statement/Profile Statement

The LOINC® codes are copyright © 1994-2018, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf