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How Marfan Syndrome is Diagnosed

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Marfan syndrome is diagnosed using the 2010 Revised Ghent criteria, which focus on two primary features: aortic root enlargement and eye lens dislocation. Doctors also use a systemic score checklist of physical signs and FBN1 genetic testing to confirm the diagnosis.

Key Takeaways

  • • Diagnosis is standardized using the 2010 Revised Ghent Nosology, a specific point-based clinical checklist.
  • • The two primary diagnostic features are aortic root dilation (measured by a Z-score) and ectopia lentis (lens dislocation).
  • • A systemic score of 7 or higher based on physical signs like scoliosis and chest deformities indicates significant systemic involvement.
  • • Genetic testing for an FBN1 gene mutation is highly effective for confirming the diagnosis, especially in borderline cases.
  • • Having a documented family history of Marfan syndrome reduces the number of clinical features required for a positive diagnosis.

Diagnosing Marfan syndrome was once a complicated process, but it is now standardized through a set of guidelines called the 2010 Revised Ghent Nosology [1]. These criteria help doctors distinguish Marfan syndrome from other similar conditions by focusing on a few “cardinal” features and a point-based checklist of physical signs [1][2].

The Two Cardinal Features

There are two primary features that doctors look for first. If both are present, a diagnosis can often be made even without genetic testing [3][4].

  1. Aortic Root Dilation: This is the widening or bulging of the aorta where it meets the heart [5]. To measure this, doctors use a Z-score [6].
    • What is a Z-score? It is a statistical measure that compares the size of your aorta to the “normal” size for a person of your same age, sex, and body size [6].
    • The Threshold: In adults, a Z-score of 2.0 or higher is considered enlarged [7]. For children and teens under 20, a Z-score of 2.0 or higher is also the threshold when other symptoms (like a family history, lens dislocation, or an FBN1 mutation) are present [7][5]. However, if a child has no other signs or genetic confirmation, doctors use a stricter threshold of a Z-score of 3.0 or higher to avoid a premature or incorrect diagnosis [6].
  2. Ectopia Lentis (Lens Dislocation): This is when the lens of the eye shifts out of its normal position [8]. It is a very specific sign of Marfan syndrome and is found in about 50% to 80% of cases [8][9].

The Systemic Score Checklist

If a person has an enlarged aorta but no lens dislocation (or vice versa), doctors use a “systemic score” to see if enough other physical signs are present [10]. A score of 7 points or more (out of a possible 20) is considered a positive finding for systemic involvement [11][7].

Feature Points
Wrist and Thumb Sign (Both overlap) 3
Wrist OR Thumb Sign (Only one overlaps) 1
Pectus Carinatum (Pigeon chest deformity) 2
Pectus Excavatum (Sunken chest) or chest asymmetry 1
Hindfoot Deformity (Specific ankle/foot alignment) 2
Flat Feet (Pes planus) 1
Pneumothorax (History of a collapsed lung) 2
Dural Ectasia (Widening of the sac around the spinal cord) 2
Protrusio Acetabuli (Deepening of the hip socket) 2
Scoliosis or Kyphosis (Curvature of the spine) 1
Reduced Elbow Extension (Inability to fully straighten arms) 1
Facial Features (3 of 5 specific signs) 1
Skin Striae (Stretch marks not related to weight change) 1
Myopia (Nearsightedness greater than 3 diopters) 1
Mitral Valve Prolapse (A specific heart valve issue) 1

The Role of Genetic Testing

Genetic testing for a mutation in the FBN1 gene is a powerful tool in the diagnostic process. While not every person with Marfan syndrome will have a mutation found, identifying one can confirm the diagnosis [2][4]. It is especially helpful in cases where the clinical signs are “borderline” or when testing family members who may not show symptoms yet [12][13].

Putting It All Together

Doctors use these pieces of evidence differently depending on your family history [14]:

  • No Family History: Diagnosis requires both cardinal features (aorta and lens) OR one cardinal feature plus a confirmed FBN1 mutation or a systemic score of 7+ [15][16].
  • With Family History: If a parent or sibling is already diagnosed, you may only need one cardinal feature (either the aorta or the lens) or a systemic score of 7+ to be diagnosed yourself [14][17].

Frequently Asked Questions

How is an enlarged aorta measured for a Marfan syndrome diagnosis?
Doctors use a Z-score to measure the aorta, which compares its size to what is normal for a person of your age, sex, and body size. In adults, a Z-score of 2.0 or higher is considered enlarged and serves as a major diagnostic feature.
What is the systemic score for Marfan syndrome?
The systemic score is a 20-point checklist of physical features, such as chest wall deformities, flat feet, and scoliosis. A score of 7 or more points indicates significant systemic involvement and helps diagnose patients who may not have all the primary features.
Can I have Marfan syndrome if my FBN1 genetic test is negative?
Yes, you can still be diagnosed with Marfan syndrome even if your genetic test is negative. While finding an FBN1 gene mutation helps confirm the diagnosis, not every person with the condition will have an identifiable genetic mutation.
How does family history affect a Marfan syndrome diagnosis?
Having a parent or sibling already diagnosed with Marfan syndrome lowers the clinical threshold required for your own diagnosis. With a confirmed family history, you may only need one primary feature, such as an enlarged aorta or dislocated lens, to be diagnosed.
What is ectopia lentis and why is it important?
Ectopia lentis is the medical term for when the lens of the eye shifts out of its normal position. It is a highly specific sign of Marfan syndrome and is found in over half of all patients with the condition.

Questions for Your Doctor

  • • What is my current aortic Z-score, and how was it calculated based on my height and weight?
  • • Is my 'systemic score' documented in my medical records?
  • • If my genetic test for FBN1 was negative, does that mean I definitely don't have Marfan syndrome?
  • • Are there other family members you recommend should be screened based on my diagnosis?
  • • Which specific features of the Ghent criteria led to my diagnosis?

Questions for You

  • • Do I have a documented family history of Marfan syndrome or aortic problems?
  • • Have I had a dilated eye exam recently to check for lens dislocation?
  • • What physical features, like scoliosis or chest shape, did I first notice or discuss with my doctor?

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References

  1. 1

    Perspectives on the revised Ghent criteria for the diagnosis of Marfan syndrome.

    von Kodolitsch Y, De Backer J, Schüler H, et al.

    The application of clinical genetics 2015; (8()):137-55 doi:10.2147/TACG.S60472.

    PMID: 26124674
  2. 2

    Mutation analysis of the FBN1 gene in a cohort of patients with Marfan Syndrome: A 10-year single center experience.

    Mannucci L, Luciano S, Salehi LB, et al.

    Clinica chimica acta; international journal of clinical chemistry 2020; (501()):154-164 doi:10.1016/j.cca.2019.10.037.

    PMID: 31730815
  3. 3

    Differences in Cardiovascular Manifestation of Marfan Syndrome Between Children and Adults.

    Wozniak-Mielczarek L, Sabiniewicz R, Drezek-Nojowicz M, et al.

    Pediatric cardiology 2019; (40(2)):393-403 doi:10.1007/s00246-018-2025-2.

    PMID: 30417312
  4. 4

    A previously undescribed pathogenic variant in FBN1 gene causing Marfan syndrome: a case report.

    Suliman A, Yan W, Yamashita MH, et al.

    European heart journal. Case reports 2022; (6(3)):ytac063 doi:10.1093/ehjcr/ytac063.

    PMID: 35372756
  5. 5

    Clinical Characteristics of Marfan Syndrome in Korea.

    Lim AY, Song JS, Kim EK, et al.

    Korean circulation journal 2016; (46(6)):841-845 doi:10.4070/kcj.2016.46.6.841.

    PMID: 27826344
  6. 6

    Comparison of Evolution of Aortic Root Dilation and Ghent Criteria in Preadolescents and Adolescents with and without Marfan Syndrome.

    Monteil DC, Shikany A, Aljeaid D, et al.

    The Journal of pediatrics 2020; (221()):188-195.e1 doi:10.1016/j.jpeds.2020.03.005.

    PMID: 32446479
  7. 7

    Marfan syndrome and related connective tissue disorders in the current era in Switzerland in 103 patients: medical and surgical management and impact of genetic testing.

    Bombardieri E, Rohrbach M, Greutmann M, et al.

    Swiss medical weekly 2020; (150()):w20189.

    PMID: 32242911
  8. 8

    Management Strategies of Ocular Abnormalities in Patients with Marfan Syndrome: Current Perspective.

    Esfandiari H, Ansari S, Mohammad-Rabei H, Mets MB

    Journal of ophthalmic & vision research 2019; (14(1)):71-77 doi:10.4103/jovr.jovr_29_18.

    PMID: 30820290
  9. 9

    Diverse presentations of ectopia lentis and lens coloboma in Marfan's syndrome.

    Dhiman R, Kaur L, Sharma N, Pandey ML

    Oman journal of ophthalmology 2023; (16(2)):310-313 doi:10.4103/ojo.ojo_108_22.

    PMID: 37602182
  10. 10

    Clinical profile and outcome of ocular manifestation in Marfans syndrome in India.

    Shah S, Shah M, Chandane P, et al.

    Indian journal of ophthalmology 2022; (70(2)):626-629 doi:10.4103/ijo.IJO_1651_21.

    PMID: 35086250
  11. 11

    The Musculoskeletal Manifestations of Marfan Syndrome: Diagnosis, Impact, and Management.

    Pollock L, Ridout A, Teh J, et al.

    Current rheumatology reports 2021; (23(11)):81 doi:10.1007/s11926-021-01045-3.

    PMID: 34825999
  12. 12

    Genetic testing of the FBN1 gene in Chinese patients with Marfan/Marfan-like syndrome.

    Yang H, Luo M, Chen Q, et al.

    Clinica chimica acta; international journal of clinical chemistry 2016; (459()):30-35 doi:10.1016/j.cca.2016.05.021.

    PMID: 27234404
  13. 13

    Clinical relevance of genotype-phenotype correlations beyond vascular events in a cohort study of 1500 Marfan syndrome patients with FBN1 pathogenic variants.

    Arnaud P, Milleron O, Hanna N, et al.

    Genetics in medicine : official journal of the American College of Medical Genetics 2021; (23(7)):1296-1304 doi:10.1038/s41436-021-01132-x.

    PMID: 33731877
  14. 14

    Revised Ghent Criteria is Comparable to Original Diagnostic Criteria for Marfan Syndrome with Increased Ability to Clinically Diagnose Related Disorders.

    Penpattharakul W, Pithukpakorn M

    Journal of the Medical Association of Thailand = Chotmaihet thangphaet 2016; (99(1)):34-9.

    PMID: 27455822
  15. 15

    Peripartum type B aortic dissection in patients with Marfan syndrome who underwent aortic root replacement: a case series study.

    Sayama S, Takeda N, Iriyama T, et al.

    BJOG : an international journal of obstetrics and gynaecology 2018; (125(4)):487-493 doi:10.1111/1471-0528.14635.

    PMID: 28294527
  16. 16

    An integrated clinical and molecular study of a cohort of Turkish patients with Marfan syndrome harboring known and novel FBN1 variants.

    Gezdirici A, Teralı K, Gülec EY, et al.

    Journal of human genetics 2021; (66(7)):647-657 doi:10.1038/s10038-021-00899-w.

    PMID: 33483584
  17. 17

    Prevalence, incidence, and age at diagnosis in Marfan Syndrome.

    Groth KA, Hove H, Kyhl K, et al.

    Orphanet journal of rare diseases 2015; (10()):153 doi:10.1186/s13023-015-0369-8.

    PMID: 26631233

This page explains the clinical diagnostic criteria for Marfan syndrome for educational purposes only. Always consult a geneticist, cardiologist, or your healthcare provider for an official medical evaluation and diagnosis.

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