Table 2.

Molecular Genetic Testing Used in FBN1-Related Marfan Syndrome

Gene 1MethodProportion of Probands with a Pathogenic Variant 2 Detectable by Method
FBN1 Sequence analysis 3~90%-93% 4
Gene-targeted deletion/duplication analysis 5~5% 6
1.
2.

See Molecular Genetics for information on variants detected in this gene.

3.

Sequence analysis detects variants that are benign, likely benign, of uncertain significance, likely pathogenic, or pathogenic. Variants may include missense, nonsense, and splice site variants and small intragenic deletions/insertions; typically, exon or whole-gene deletions/duplications are not detected. For issues to consider in interpretation of sequence analysis results, click here.

4.

In individuals with classic Marfan syndrome an FBN1 pathogenic variant was identified by sequence analysis in 86 (93%) of 93 [Loeys et al 2004] and 76 (91%) of 87 individuals [Baetens et al 2011]. Subsequently, a number of these individuals were found to have FBN1 deletions that had not been detected by sequencing [Bart Loeys, personal communication].

5.

Gene-targeted deletion/duplication analysis detects intragenic deletions or duplications. Methods used may include a range of techniques such as quantitative PCR, long-range PCR, multiplex ligation-dependent probe amplification (MLPA), and a gene-targeted microarray designed to detect single-exon deletions or duplications.

6.

Deletions and duplications ranging in size from one to multiple exons as well as full-gene deletions have been described (www​.hgmd.cf.ac.uk). In one systematic study, four of 86 individuals with classic Marfan syndrome had a large deletion or duplication [Baetens et al 2011].

From: FBN1-Related Marfan Syndrome

Cover of GeneReviews®
GeneReviews® [Internet].
Adam MP, Feldman J, Mirzaa GM, et al., editors.
Seattle (WA): University of Washington, Seattle; 1993-2025.
Copyright © 1993-2025, University of Washington, Seattle. GeneReviews is a registered trademark of the University of Washington, Seattle. All rights reserved.

GeneReviews® chapters are owned by the University of Washington. Permission is hereby granted to reproduce, distribute, and translate copies of content materials for noncommercial research purposes only, provided that (i) credit for source (http://www.genereviews.org/) and copyright (© 1993-2025 University of Washington) are included with each copy; (ii) a link to the original material is provided whenever the material is published elsewhere on the Web; and (iii) reproducers, distributors, and/or translators comply with the GeneReviews® Copyright Notice and Usage Disclaimer. No further modifications are allowed. For clarity, excerpts of GeneReviews chapters for use in lab reports and clinic notes are a permitted use.

For more information, see the GeneReviews® Copyright Notice and Usage Disclaimer.

For questions regarding permissions or whether a specified use is allowed, contact: ude.wu@tssamda.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.