Marfan Syndrome Panel

Last modified: Jun 12, 2018

Summary

  • Is a 30 gene panel that includes assessment of non-coding variants
  • Is ideal for patients with a clinical suspicion of Marfan syndrome or a related disorder.

Analysis methods

  • PLUS
  • SEQ
  • DEL/DUP

Availability

4 weeks

Number of genes

30

Test code

CA0801

Panel size

Large

CPT codes

SEQ 81410
DEL/DUP 81411

Summary

The Blueprint Genetics Marfan Syndrome Panel (test code CA0801):

  • Is a 30 gene panel that includes assessment of selected non-coding disease-causing variants
  • Is available as PLUS analysis (sequencing analysis and deletion/duplication analysis), sequencing analysis only or deletion/duplication analysis only

ICD codes

Commonly used ICD-10 code(s) when ordering the Marfan Syndrome Panel

ICD-10 Disease
Q87.40 Marfan syndrome
Q87.89 Loeys-Dietz syndrome
Q87.89 Shprintzen-Goldberg syndrome
Q79.6 Ehlers-Danlos syndrome
Q87.89 Arterial tortuosity syndrome
Q87.89 Congenital contractural arachnodactyly

Sample Requirements

  • EDTA blood, min. 1 ml
  • Purified DNA, min. 3μg
  • Saliva (Oragene DNA OG-500 kit)

Label the sample tube with your patient’s name, date of birth and the date of sample collection.

Note that we do not accept DNA samples isolated from formalin-fixed paraffin-embedded (FFPE) tissue.

The diagnosis of Marfan syndrome can be difficult as many of the features are also identified in normal population, features may appear in an age-dependent manner and there is substantial phenotypic variability between patients. There is also considerable overlap with other connective-tissue disorders such as Loeys-Dietz syndrome (LDS), Ehlers-Danlos syndromes, arterial tortuosity syndrome, Shprintzen-Goldberg syndrome and congenital contractural arachnodactyly (CCA). The Marfan Syndrome Panel is designed as a genetic diagnostic tool for patients with clinical features of Marfan syndrome. The two major features of Marfan syndrome are vision problems caused by a dislocated lens (ectopia lentis) in one or both eyes and arterial aneurysms and dissection involving especially aorta. Aortic aneurysm and dissection can be life threatening. Mitral valve regurgitation is another cardiovascular issue associated with disorder. Individuals with Marfan syndrome are usually tall and slender, have elongated fingers and toes, and have an arm span that exceeds their body height. Other common features include crowded teeth, a long and narrow face, dural ectasia, an abnormal curvature of the spine, and chest abnormalities. The features of Marfan syndrome can become apparent anytime between infancy and adulthood. Depending on the age of diagnosis and severity of symptoms, Marfan syndrome can be fatal early in life; however, the majority of affected individuals survive into mid- to late adulthood.

Genes in the Marfan Syndrome Panel and their clinical significance

Gene Associated phenotypes Inheritance ClinVar HGMD
ABL1 Congenital heart defects and skeletal malformations syndrome (CHDSKM) AD 30 3
ADAMTS10 Weill-Marchesani syndrome AR 8 13
ADAMTS17 Weill-Marchesani-like syndrome AR 6 7
ADAMTSL4 Ectopia lentis, isolated AR 11 26
BGN Spondyloepimetaphyseal dysplasia, X-linked, Meester-Loeys syndrome XL 8 7
CBS Homocystinuria due to cystathionine beta-synthase deficiency AR 72 187
COL1A1 Ehlers-Danlos syndrome, Caffey disease, Osteogenesis imperfecta type 1, Osteogenesis imperfecta type 2, Osteogenesis imperfecta type 3, Osteogenesis imperfecta type 4 AD 290 943
COL1A2 Ehlers-Danlos syndrome, cardiac valvular form, Osteogenesis imperfecta type 1, Osteogenesis imperfecta type 2, Osteogenesis imperfecta type 3, Osteogenesis imperfecta type 4 AD/AR 162 496
COL2A1 Avascular necrosis of femoral head, Rhegmatogenous retinal detachment, Epiphyseal dysplasia, with myopia and deafness, Czech dysplasia, Achondrogenesis type 2, Platyspondylic dysplasia Torrance type, Hypochondrogenesis, Spondyloepiphyseal dysplasia congenital (SEDC), Spondyloepimetaphyseal dysplasia (SEMD) Strudwick type, Kniest dysplasia, Spondyloperipheral dysplasia, Mild SED with premature onset arthrosis, SED with metatarsal shortening, Stickler syndrome type 1 AD 166 544
COL3A1 Ehlers-Danlos syndrome AD 499 625
COL5A1 Ehlers-Danlos syndrome AD 84 151
COL5A2 Ehlers-Danlos syndrome AD 21 34
COL11A1 Marshall syndrome, Fibrochondrogenesis, Stickler syndrome type 2 AD/AR 30 86
COL11A2 Weissenbacher-Zweymuller syndrome, Deafness, Otospondylomegaepiphyseal dysplasia, Fibrochondrogenesis, Stickler syndrome type 3 (non-ocular) AD/AR 28 55
EFEMP2 Cutis laxa AR 12 15
FBN1 MASS syndrome, Marfan syndrome, Acromicric dysplasia, Geleophysic dysplasia AD 919 2548
FBN2 Congenital contractural arachnodactyly (Beals syndrome) AD 45 95
MAT2A* Complement system AD/AR 2
MED12 Ohdo syndrome, Mental retardation, with Marfanoid habitus, FG syndrome, Opitz-Kaveggia syndrome, Lujan-Fryns syndrome XL 29 27
PLOD1 Ehlers-Danlos syndrome AR 27 39
SKI Shprintzen-Goldberg syndrome AD 17 21
SLC2A10 Arterial tortuosity syndrome AR 22 30
SMAD3 Aneurysms-osteoarthritis syndrome, Loeys-Dietz syndrome AD 43 55
SMAD6 Craniosynostosis 7 AD 4 33
TGFB2 Loeys-Dietz syndrome AD 34 28
TGFB3 Loeys-Dietz syndrome (Reinhoff syndrome), Arrhythmogenic right ventricular dysplasia AD 17 22
TGFBR1 Loeys-Dietz syndrome AD 37 69
TGFBR2 Loeys-Dietz syndrome AD 58 136
UPF3B Mental retardation, syndromic XL 9 18
VCAN Wagner disease AD 11 19

* Some, or all, of the gene is duplicated in the genome. Read more.

# The gene has suboptimal coverage (means <90% of the gene’s target nucleotides are covered at >20x with mapping quality score (MQ>20) reads).

The sensitivity to detect variants may be limited in genes marked with an asterisk (*) or number sign (#)

Gene refers to the HGNC approved gene symbol; Inheritance refers to inheritance patterns such as autosomal dominant (AD), autosomal recessive (AR), X-linked (XL), X-linked dominant (XLD) and X-linked recessive (XLR); ClinVar refers to the number of variants in the gene classified as pathogenic or likely pathogenic in this database (ClinVar); HGMD refers to the number of variants with possible disease association in the gene listed in Human Gene Mutation Database (HGMD). The list of associated, gene specific phenotypes are generated from CGD or Orphanet databases.

Non-coding variants covered by the panel

Gene Genomic location HG19 HGVS RefSeq RS-number
COL11A1 Chr1:103488576 c.1027-24A>G NM_080629.2
COL11A1 Chr1:103386637 c.3744+437T>G NM_080629.2
COL11A1 Chr1:103491958 c.781-450T>G NM_080629.2 rs587782990
COL1A1 Chr17:48272201 c.1354-12G>A NM_000088.3 rs72648337
COL1A1 Chr17:48268147 c.2343+31T>A NM_000088.3
COL1A1 Chr17:48267611 c.2451+77C>T NM_000088.3 rs72651665
COL1A1 Chr17:48267594 c.2451+94G>T NM_000088.3
COL1A1 Chr17:48273742 c.904-14G>A NM_000088.3
COL1A2 Chr7:94025130 c.70+717A>G NM_000089.3 rs72656354
COL2A1 Chr12:48379984 c.1527+135G>A NM_001844.4
COL3A1 Chr2:189872183 c.3256-43T>G NM_000090.3 rs587779667
COL5A1 Chr9:137680989 c.2647-12A>G NM_000093.4
COL5A1 Chr9:137686903 c.2701-25T>G NM_000093.4 rs765079080
COL5A1 Chr9:137726806 c.5137-11T>A NM_000093.4 rs183495554
FBN1 Chr15:48739106 c.5672-87A>G NM_000138.4
FBN1 Chr15:48739107 c.5672-88A>G NM_000138.4
FBN1 Chr15:48720682 c.6872-14A>G NM_000138.4
FBN1 Chr15:48721629 c.6872-961A>G NM_000138.4
FBN1 Chr15:48707358 c.8051+375G>T NM_000138.4
FBN1 Chr15:48818478 c.863-26C>T NM_000138.4
FBN2 Chr5:127671284 c.3725-15A>G NM_001999.3
FBN2 Chr5:127670560 c.3974-24A>C NM_001999.3
FBN2 Chr5:127670562 c.3974-26T>G NM_001999.3
TGFB3 Chr14:76425035 c.*495C>T NM_003239.2 rs387906514
TGFB3 Chr14:76447266 c.-30G>A NM_003239.2 rs770828281
TGFBR2 Chr3:30648317 c.-59C>T NM_001024847.2

Added and removed genes from the panel

Genes added Genes removed
ABL1
ADAMTS10
ADAMTS17
BGN
COL11A2
EFEMP2
MAT2A
SMAD6
COL18A1
COL9A1
COL9A2

Test strength

The strengths of this test include:
  • CAP and ISO-15189 accreditations covering all operations at Blueprint Genetics including all Whole Exome Sequencing, NGS panels and confirmatory testing
  • CLIA-certified personnel performing clinical testing in a CLIA-certified laboratory
  • Powerful sequencing technologies, advanced target enrichment methods and precision bioinformatics pipelines ensure superior analytical performance
  • Careful construction of clinically effective and scientifically justified gene panels
  • Our Nucleus online portal providing transparent and easy access to quality and performance data at the patient level
  • Our publically available analytic validation demonstrating complete details of test performance
  • ~1,500 non-coding disease causing variants in Blueprint WES assay (please see below ‘Non-coding disease causing variants covered by this panel’)
  • Our rigorous variant classification based on modified ACMG variant classification scheme
  • Our systematic clinical interpretation workflow using proprietary software enabling accurate and traceable processing of NGS data
  • Our comprehensive clinical statements

Test limitations

Genes with partial, or whole gene, segmental duplications in the human genome are marked with an asterisk (*) if they overlap with the UCSC pseudogene regions. The technology may have limited sensitivity to detect variants in genes marked with these symbols (please see the Panel content table above).

This test does not detect the following:
  • Complex inversions
  • Gene conversions
  • Balanced translocations
  • Mitochondrial DNA variants
  • Repeat expansion disorders unless specifically mentioned
  • Non-coding variants deeper than ±20 base pairs from exon-intron boundary unless otherwise indicated (please see above Panel Content / non-coding variants covered by the panel).

This test may not reliably detect the following:

  • Low level mosaicism (variant with a minor allele fraction of 14.6% is detected with 90% probability)
  • Stretches of mononucleotide repeats
  • Indels larger than 50bp
  • Single exon deletions or duplications
  • Variants within pseudogene regions/duplicated segments

The sensitivity of this test may be reduced if DNA is extracted by a laboratory other than Blueprint Genetics.

For additional information, please refer to the Test performance section and see our Analytic Validation.

The Blueprint Genetics Marfan syndrome panel covers classical genes associated with aortic dissection, thoracic aorta, Marfan syndrome, Loeys-Dietz syndrome, Shprintzen-Goldberg syndrome, Ehlers-Danlos syndrome, Arterial tortuosity syndrome, congenital contractural arachnodactyly, aortic aneurysm, thoracic aorta, aortic aneurysm, ruptured, thoracic aorta, aortic aneurysm, ruptured, abdominal aorta and aortic aneurysm, ruptured, unspecific site. The genes on the panel have been carefully selected based on scientific literature, mutation databases and our experience.

Our panels are sliced from our high-quality whole exome sequencing data. Please see our sequencing and detection performance table for different types of alterations at the whole exome level (Table).

Assays have been validated for different starting materials including EDTA-blood, isolated DNA (no FFPE), saliva and dry blood spots (filter card) and all provide high-quality results. The diagnostic yield varies substantially depending on the assay used, referring healthcare professional, hospital and country. Blueprint Genetics’ Plus Analysis (Seq+Del/Dup) maximizes the chance to find a molecular genetic diagnosis for your patient although Sequence Analysis or Del/Dup Analysis may be a cost-effective first line test if your patient’s phenotype is suggestive of a specific mutation type.

Performance of Blueprint Genetics Whole Exome Sequencing (WES) assay. All individual panels are sliced from WES data.

Sensitivity % (TP/(TP+FN) Specificity %
Single nucleotide variants 99.65% (412,456/413,893) >99.99%
Insertions, deletions and indels by sequence analysis
1-10 bps 96.94% (17,070/17,608) >99.99%
11-50 bps 99.07% (957/966) >99.99%
Copy number variants (exon level dels/dups)
Clinical samples (small CNVs, n=52)
1 exon level deletion 92.3% (24/26) NA
2 exons level deletion/duplication 100.0% (11/11) NA
3-7 exons level deletion/duplication 93.3% (14/15) NA
Microdeletion/-duplication sdrs (large CNVs, n=37))
Size range (0.1-47 Mb) 100% (37/37)
Simulated CNV detection
2 exons level deletion/duplication 90.98% (7,357/8,086) 99.96%
5 exons level deletion/duplication 98.63% (7,975/8,086) 99.98%
     
The performance presented above reached by WES with the following coverage metrics
     
Mean sequencing depth at exome level 174x
Nucleotides with >20x sequencing coverage (%) 99.4%

Bioinformatics

The target region for each gene includes coding exons and ±20 base pairs from the exon-intron boundary. In addition, the panel includes non-coding variants if listed above (Non-coding variants covered by the panel). Some regions of the gene(s) may be removed from the panel if specifically mentioned in the ‘Test limitations” section above. The sequencing data generated in our laboratory is analyzed with our proprietary data analysis and annotation pipeline, integrating state-of-the art algorithms and industry-standard software solutions. Incorporation of rigorous quality control steps throughout the workflow of the pipeline ensures the consistency, validity and accuracy of results. Our pipeline is streamlined to maximize sensitivity without sacrificing specificity. We have incorporated a number of reference population databases and mutation databases such as, but not limited, to 1000 Genomes Project, gnomAD, ClinVar and HGMD into our clinical interpretation software to make the process effective and efficient. For missense variants, in silico variant prediction tools such as SIFT, PolyPhen, MutationTaster are used to assist with variant classification. Through our online ordering and statement reporting system, Nucleus, the customer has an access to details of the analysis, including patient specific sequencing metrics, a gene level coverage plot and a list of regions with inadequate coverage if present. This reflects our mission to build fully transparent diagnostics where customers have easy access to crucial details of the analysis process.

Clinical interpretation

We provide customers with the most comprehensive clinical report available on the market. Clinical interpretation requires a fundamental understanding of clinical genetics and genetic principles. At Blueprint Genetics, our PhD molecular geneticists, medical geneticists and clinical consultants prepare the clinical statement together by evaluating the identified variants in the context of the phenotypic information provided in the requisition form. Our goal is to provide clinically meaningful statements that are understandable for all medical professionals regardless of whether they have formal training in genetics.

Variant classification is the corner stone of clinical interpretation and resulting patient management decisions. Our classifications follow the Blueprint Genetics Variant Classification Schemes based on the ACMG guideline 2015. Minor modifications were made to increase reproducibility of the variant classification and improve the clinical validity of the report. Our experience with tens of thousands of clinical cases analyzed at our laboratory allowed us to further develop the industry standard.

The final step in the analysis of sequence variants is confirmation of variants classified as pathogenic or likely pathogenic using bi-directional Sanger sequencing. Variant(s) fulfilling all of the following criteria are not Sanger confirmed: 1) the variant quality score is above the internal threshold for a true positive call, 2) an unambiguous IGV in-line with the variant call and 3) previous Sanger confirmation of the same variant at least three times at Blueprint Genetics. Reported variants of uncertain significance are confirmed with bi-directional Sanger sequencing only if the quality score is below our internally defined quality score for true positive call. Reported copy number variations with a size <10 exons are confirmed by orthogonal methods such as qPCR if the specific CNV has been seen less than three times at Blueprint Genetics.

Our clinical statement includes tables for sequencing and copy number variants that include basic variant information (genomic coordinates, HGVS nomenclature, zygosity, allele frequencies, in silico predictions, OMIM phenotypes and classification of the variant). In addition, the statement includes detailed descriptions of the variant, gene and phenotype(s) including the role of the specific gene in human disease, the mutation profile, information about the gene’s variation in population cohorts and detailed information about related phenotypes. We also provide links to the references used, congress abstracts and mutation databases to help our customers further evaluate the reported findings if desired. The conclusion summarizes all of the existing information and provides our rationale for the classification of the variant.

Identification of pathogenic or likely pathogenic variants in dominant disorders or their combinations in different alleles in recessive disorders are considered molecular confirmation of the clinical diagnosis. In these cases, family member testing can be used for risk stratification within the family. In the case of variants of uncertain significance (VUS), we do not recommend family member risk stratification based on the VUS result. Furthermore, in the case of VUS, we do not recommend the use of genetic information in patient management or genetic counseling.

Our interpretation team analyzes millions of variants from thousands of individuals with rare diseases. Thus, our database, and our understanding of variants and related phenotypes, is growing by leaps and bounds. Our laboratory is therefore well positioned to re-classify previously reported variants as new information becomes available. If a variant previously reported by Blueprint Genetics is re-classified, our laboratory will issue a follow-up statement to the original ordering health care provider at no additional cost.