Marfan Syndrome (FBN1) Sequencing and Deletion/Duplication

Background information for Marfan Syndrome (FBN1) Sequencing and Deletion/Duplication:
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.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.