Preferred test to confirm diagnosis when Marfan syndrome is strongly suspected by consensus criteria.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA) or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 2 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Aortic root dilatation/dissection, ectopia lentis, positive wrist and/or thumb sign, pectus carinatum or excavatum, hindfoot deformity, pneumothorax, dural ectasia, acetabular protrusion, scoliosis or thoracolumbar kyphosis, reduced upper/lower segment ratio and increased arm/height ratio in persons without severe scoliosis, reduced elbow extension, skin striae, myopia, mitral valve prolapse, and characteristic facial features.
Prevalence: 1 in 5,000-1 in 10,000.
Inheritance: Autosomal dominant.
Penetrance: 100 percent, age-dependent.
Cause: Pathogenic FBN1 gene mutations.
Clinical Sensitivity: 70-93 percent for sequencing, unknown for deletion/duplication analysis.
Methodology: Bidirectional sequencing of the entire FBN1 coding region and intron-exon boundaries. Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large FBN1 coding region deletions/duplications.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations and deep intronic mutations will not be detected. Large deletions/duplications of exon 40 may or may not be detected depending on the location of breakpoints. The breakpoints of large deletions/duplications will not be determined. Mutations in genes other than FBN1 are not evaluated.
|Component Test Code*||Component Chart Name||LOINC|
|2005585||Marfan Syndrome (FBN1) Seq, Del/Dup Spcm||31208-2|
|2005586||Marfan Syndrome (FBN1) Seq, Del/Dup Int||40471-5|
- FBN1 genetic
- FBN1 Sequencing and Deletion/Duplication
- FBN1 sequencing and deletion/duplication assay