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.