Marfan syndrome
Enable an AI agent to organize evidence for recognizing Marfan syndrome, assess its manifestations over time, and identify appropriate clinician-reviewed surveillance, referral, and management decisions.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to organize evidence for recognizing Marfan syndrome, assess its manifestations over time, and identify appropriate clinician-reviewed surveillance, referral, and management decisions.
Marfan syndrome is an autosomal-dominant heritable connective-tissue disorder, usually caused by pathogenic variants in FBN1, that produces a variable combination of aortic-root aneurysm or dissection, ectopia lentis, and a systemic skeletal and dural phenotype scored by the revised Ghent nosology.
It can be Assemble a diagnostic evidence summary and identify missing or conflicting observations for specialist review.; Compare compatible aortic measurements and flag changes against the person's documented escalation criteria.; Track due and overdue aortic, ophthalmic, and other manifestation-specific assessments.; Identify relatives for whom clinician-led evaluation should be considered, subject to consent and access permissions.; Prepare an attributed review of treatment tolerance, activity constraints, and reproductive-care needs.; Route reported warning symptoms through an approved urgent-assessment pathway without asserting the cause..
Distinguishing features
Evaluate the combination of aortic-root findings, ectopia lentis, systemic features, and family history through a documented diagnostic pathway; tall stature alone is insufficient. [GeneReviews](https://www.ncbi.nlm.nih.gov/books/NBK1335/)
Check whether an FBN1 result supports Marfan syndrome specifically rather than assuming every FBN1-associated phenotype is Marfan syndrome. [GeneReviews](https://www.ncbi.nlm.nih.gov/books/NBK1335/)
For suspected Loeys-Dietz syndrome or vascular Ehlers-Danlos syndrome, require a recorded differential assessment and relevant molecular evidence before resolving the classification. [GeneReviews](https://www.ncbi.nlm.nih.gov/books/NBK1335/)
Distinguish an incomplete childhood presentation from a settled alternative diagnosis by recording age and serial reassessment. [GeneReviews](https://www.ncbi.nlm.nih.gov/books/NBK1335/)
Scope
+ Diagnostic status and the evidence supporting or challenging a Marfan syndrome classification.
+ Aortic, valvular, ocular, skeletal, and other connective-tissue manifestations attributed to the syndrome.
+ FBN1 findings, their interpretation, and relevant family relationships.
+ Manifestation trajectories, including incomplete childhood presentations and severe early-onset disease.
+ Syndrome-specific surveillance, escalation, activity, and reproductive-care considerations.
- Independent diagnostic and management models for Loeys-Dietz syndrome, vascular Ehlers-Danlos syndrome, and other differential diagnoses.
- Laboratory sequencing methods and general variant-classification machinery.
- Full episode models for aortic dissection, retinal detachment, pneumothorax, or heart failure.
- Drug prescribing, dosing, and surgical procedure specifications.
- The person's complete medical record and unrelated conditions.
Characteristics
- Diagnostic standing
- suspected | provisional | confirmed | disputed | excluded; dated and attributed Separates recognition signals from a clinician-established diagnosis.
- Diagnostic pathway
- Named criteria and version, family-history branch, satisfied conditions, unresolved conditions Makes the classification auditable without reducing it to a single score.
- FBN1 evidence
- Linked laboratory report, variant identity, classification, interpretation date, and phenotype association Preserves the evidence behind molecular attribution.
- Aortic-root dimension
- mm and dimensionless Z-score, with date, anatomical level, imaging method, body-size inputs, and reference equation Supports comparison while exposing measurement and normalization differences.
- Aortic change
- mm/year over a stated interval, with comparability assessment Distinguishes an observed trajectory from isolated or incompatible measurements.
- Ectopia lentis assessment
- present | absent on examination | indeterminate | not assessed; laterality and examination date Preserves an important diagnostic observation without equating missing evidence with absence.
- Systemic feature score
- Points under named criteria, with component evidence and assessment completeness Allows reconstruction of the score and detection of unsupported components.
- Manifestation burden
- Per manifestation: presence, severity, symptoms, functional impact, trajectory, and attribution confidence Avoids hiding different organ states behind one global severity label.
- Family evidence
- Linked relative, relationship, verified diagnosis or variant, and relevant aortic-event history Supports diagnostic interpretation and family evaluation.
- Care-context modifiers
- Age and growth phase; pregnancy or postpartum status; prior aortic repair or dissection; planned physical demands Makes the circumstances of surveillance and intervention decisions explicit.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Diagnostic identity Records why this presentation is classified as Marfan syndrome and what remains unresolved.
The registry name must be supported by an explicit diagnostic argument.
Criteria evidence
Connects the diagnostic conclusion to observations and the criteria used.
Diagnostic pathway
Record the clinician's conclusion, criteria version, applicable branch, and supporting evidence.
- Which diagnostic criteria and family-history branch were applied, and which conditions were satisfied? definition
- Who established the conclusion, on what date, and from which examination, imaging, and laboratory reports? provenance
Diagnostic boundaries
Preserves alternative explanations and reasons to revisit an incomplete classification.
Alternatives and reassessment
Record competing diagnoses, discriminating evidence, and a reassessment condition.
- What evidence distinguishes this presentation from Loeys-Dietz syndrome, vascular Ehlers-Danlos syndrome, MASS phenotype, isolated ectopia lentis, or nonsyndromic aortopathy? boundary
- If classification remains provisional, which new observation or follow-up date should trigger reassessment? action
Aortic and cardiac state Aortic-root enlargement and valve disease are important manifestations; retain their separate trajectories. [GeneReviews](https://www.ncbi.nlm.nih.gov/books/NBK1335/)
Cardiovascular decisions need anatomical, temporal, and treatment context.
Aortic trajectory
Organizes serial measurements by aortic segment and measurement convention.
Segment measurements and change
Record dimensions, normalization, comparability, prior events, and repaired anatomy.
- What are the dated root and other assessed aortic-segment dimensions, and which methods and reference equations produced them? measurement
- Which examinations are sufficiently comparable to estimate growth, and where does technique or repaired anatomy limit comparison? boundary
Cardiac impact and escalation
Connects valve and ventricular findings with individualized aortic review decisions.
Cardiovascular review state
Record the specialist's review triggers; guideline decisions incorporate dimensions and additional risk features. [ACC/AHA guideline summary](https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2022/11/01/12/21/2022-guideline-on-aortic-disease-2-gl-ad)
- What valve regurgitation, ventricular dysfunction, symptoms, or prior cardiovascular events are documented? measurement
- Which patient-specific findings trigger earlier imaging, multidisciplinary surgical review, or urgent assessment under the cited care plan? action
Ocular and systemic expression Records manifestations beyond the aorta as diagnostic evidence and sources of functional burden.
Aortic measurements alone cannot represent the person's syndrome state.
Ocular expression
Separates lens findings used in recognition from current visual-care needs.
Lens and visual state
Retain ophthalmic findings, laterality, visual function, and previous procedures.
- Was ectopia lentis assessed by an appropriate ophthalmic examination, and what was recorded for each eye? provenance
- What refractive error, visual limitation, retinal finding, glaucoma, or cataract currently requires follow-up? measurement
Systemic expression
Preserves component observations and their impact beyond a diagnostic score.
Connective-tissue burden
Record assessed skeletal, dural, pulmonary, and skin features without assuming every symptom is syndrome-related.
- Which systemic-score components were examined, what evidence supports each, and which remain unassessed? measurement
- Which features cause pain, mobility or breathing limitations, or other functional effects, and how certain is their attribution to Marfan syndrome? boundary
Molecular and family context Links molecular interpretation to family evaluation while preserving uncertainty.
A genetic label needs its report context and cannot substitute for individual clinical assessment.
Molecular interpretation
Captures what testing established and the limits of that conclusion.
Variant evidence and limits
Record reported variants, classifications, test coverage, and unresolved interpretation.
- Which FBN1 variant and classification were reported, by which laboratory, and with what evidence connecting it to this phenotype? provenance
- What does a negative, uncertain, or discordant result leave unresolved, and is reinterpretation or further testing planned? boundary
Family evaluation
Distinguishes verified familial findings from reported resemblance or unconfirmed history.
Pedigree and evaluation status
Record relevant relationships, evidence quality, and clinician-led evaluation plans.
- Which relatives have a verified diagnosis, relevant variant, or documented aortic event, and which histories remain unconfirmed? provenance
- Which relatives have an agreed evaluation pathway, and what consent or access limits govern use of their information? action
Surveillance and life context Connects the syndrome state with follow-up and decisions during changing life circumstances.
An agent needs actionable review conditions as well as descriptive findings.
Surveillance and treatment review
Records the agreed monitoring schedule and evidence needed to assess ongoing management.
Monitoring and management plan
Link assessments and treatments to their indication, responsible clinician, and review conditions.
- When are the next aortic and ophthalmic assessments due, and which findings would shorten those intervals? action
- What treatment is prescribed for cardiovascular risk or other manifestations, and what response, tolerance, or adherence concerns require review? measurement
Activity, reproduction, and transitions
Preserves individualized plans for physical demands, reproductive care, and transfer between services.
Context-specific care constraints
Pregnancy and postpartum status affect aortic-care planning. [ACC/AHA guideline summary](https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2022/11/01/12/21/2022-guideline-on-aortic-disease-2-gl-ad)
- What physical activities are planned, and which individualized limits or adaptations has the care team documented? action
- Do pregnancy planning, pregnancy, postpartum status, rapid growth, or transfer to adult care require updated imaging, medication review, or specialist coordination? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Classic Marfan syndrome (FBN1, revised Ghent-positive)
- Neonatal Marfan syndrome
- FBN1-related Marfan syndrome without ectopia lentis
- Marfan syndrome with predominant aortopathy
- Familial ectopia lentis (FBN1, limited systemic features)
- MASS phenotype (FBN1-related)
- Marfanoid-progeroid-lipodystrophy syndrome (FBN1)
- Likely Marfan syndrome pending molecular confirmation
- Which of these kinds and varieties hold for the sense of Marfan syndrome this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q190582 - Item for Marfan syndrome.
- OMIM - 154700 - Phenotype MIM number; gene MIM 134797 (FBN1).
- ORPHA - 558 - Orphanet disorder identifier.
- ICD-10 - Q87.4 - Marfan syndrome (WHO ICD-10).
- ICD-11 - LD28.01 - Marfan syndrome in ICD-11.
- MeSH - D008382 - Medical Subject Heading.
- MONDO - MONDO:0007947 - Monarch Disease Ontology class.
- GARD - 6975 - Genetic and Rare Diseases Information Center identifier.
- Which of these identifiers and schemes hold for the sense of Marfan syndrome this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Revised Ghent nosology (Loeys et al., Journal of Medical Genetics, 2010) - operational clinical diagnosis
- ACMG/AMP variant interpretation guidelines as applied to FBN1 (ClinGen FBN1 expert panel)
- 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease (American College of Cardiology / American Heart Association)
- 2024 ESC Guidelines for the management of peripheral arterial and aortic diseases (European Society of Cardiology)
- GeneReviews clinical management recommendations (University of Washington / NCBI Bookshelf)
- ICD-10 Q87.4 and ICD-11 LD28.01 coding rules (WHO)
- Which of these standards and regulation hold for the sense of Marfan syndrome this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Diagnosed in medical genetics or cardiology clinics from aortic-root dilation, ectopia lentis, family history, and a systemic Ghent score, then confirmed by FBN1 sequencing.
- Lifelong echocardiographic or CMR surveillance of the aortic root and ascending aorta to time elective valve-sparing or composite aortic-root replacement.
- Ophthalmology follow-up for lens subluxation, high myopia, and retinal detachment risk.
- Orthopaedic and physiotherapy care for scoliosis, pectus deformity, pes planus, and joint instability.
- Pregnancy counselling and high-risk obstetric care because of dissection risk, especially with aortic root ≥40 mm.
- Sports and occupational restriction (avoid isometric strain and contact collision) based on aortic dimension and surgical status.
- Cascade genetic testing of first-degree relatives once a familial FBN1 variant is known.
- Which of these real-world use hold for the sense of Marfan syndrome this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Aortic root diameter at the sinuses of Valsalva - Adult surgical threshold commonly 45-50 mm (often 50 mm; 45 mm with additional risk or family history); Z-score ≥2 used in diagnosis - mm (or aortic Z-score, dimensionless)
- Systemic Ghent score - 0-20; score ≥7 is a major diagnostic criterion in the revised nosology - points
- Steinberg (thumb) and Walker-Murdoch (wrist) signs - Present or absent; both positive contribute to the systemic score - binary clinical sign
- Arm span-to-height ratio - Often >1.05 in affected adults when used in the systemic score - dimensionless ratio
- Lens status (ectopia lentis) - Present/absent; laterality and direction of subluxation recorded - clinical/ophthalmic finding
- FBN1 variant classification - Pathogenic / likely pathogenic / VUS / benign per ACMG/AMP - ACMG class
- Which of these typical measurements hold for the sense of Marfan syndrome this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Type A aortic dissection or rupture from progressive aortic-root aneurysm - the leading cause of premature death.
- Acute aortic regurgitation and heart failure from annular or root dilation.
- Mitral-valve prolapse with regurgitation, arrhythmia, or rarely endocarditis.
- Ectopia lentis, high myopia, glaucoma, and retinal detachment.
- Dural ectasia causing low-back pain, headache, or nerve-root compression.
- Pneumothorax from apical blebs.
- Peripartum aortic dissection.
- Overdiagnosis when a marfanoid body habitus is treated as Marfan syndrome without Ghent features or FBN1 evidence, leading to unnecessary aortic surgery or activity restriction; underdiagnosis when isolated aortopathy is missed.
- Which of these failure modes and hazards hold for the sense of Marfan syndrome this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Europe more often cites ESC aortic thresholds and Orphanet/ORPHA:558; the United States more often cites ACC/AHA 2022 aortic guidelines, ICD-10-CM Q87.4, and GeneReviews.
- Elective aortic-root replacement is commonly discussed at 50 mm in many centres, and at 45 mm when additional risk factors, rapid growth, or a family history of dissection are present; Japanese and some Asian series report dissection at smaller absolute diameters, so indexed diameters and earlier surgery are sometimes used.
- The eponym remains 'Marfan syndrome' in English, French (syndrome de Marfan), and German (Marfan-Syndrom); older literature used 'dolichostenomelia' and 'arachnodactyly'.
- Neonatal Marfan syndrome is coded and counselled as a severe infantile presentation rather than a separate MIM number in most services.
- Which of these regional variation hold for the sense of Marfan syndrome this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Loeys-Dietz syndrome (TGFBR1/2, SMAD3, TGFB2/3) - Widespread arterial tortuosity, hypertelorism, bifid uvula or cleft palate, and TGF-β-pathway genes rather than FBN1; aortic events at smaller diameters.
- Vascular Ehlers-Danlos syndrome (COL3A1) - Thin translucent skin, easy bruising, hollow-organ and medium-artery rupture without the Ghent skeletal-ocular pattern; COL3A1, not FBN1.
- Congenital contractural arachnodactyly (Beals syndrome, FBN2) - Crumpled ears and congenital contractures; aortopathy uncommon; FBN2 rather than FBN1.
- Homocystinuria (CBS) - Autosomal recessive, thromboembolism, downward lens dislocation, intellectual disability, and raised plasma homocysteine/methionine; FBN1 negative.
- MASS phenotype (FBN1-related) - Mitral prolapse, myopia, borderline aortic enlargement, and skin/skeletal findings without aortic aneurysm reaching Ghent aortic criteria or ectopia lentis.
- Familial thoracic aortic aneurysm and dissection (ACTA2, MYH11, MYLK, PRKG1, etc.) - Isolated or predominant aortopathy without ectopia lentis or a high systemic score; non-FBN1 aortopathy genes.
- Shprintzen-Goldberg syndrome (SKI) - Craniosynostosis and intellectual disability with marfanoid habitus; SKI, not FBN1.
- Klinefelter syndrome (47,XXY) - Tall habitus with hypogonadism and small testes; karyotype 47,XXY, no FBN1 aortopathy pattern.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of Marfan syndrome this model covers, and on what evidence? provenance
Sources
- Marfan Syndrome - Clinical definition, FBN1 genetics, neonatal form, management, and differential diagnosis as used in medical genetics practice.
- The revised Ghent nosology for the Marfan syndrome - Operational diagnostic criteria, systemic score, and distinction from related aortopathies and MASS phenotype.
- MARFAN SYNDROME; MFS - MIM phenotype number, FBN1 locus, allelic series, and historical naming.
- 2024 ESC Guidelines for the management of peripheral arterial and aortic diseases - Aortic surveillance thresholds, activity restriction, and beta-blocker or ARB medical therapy used in European practice.
What the second pass must settle
- Which diagnostic criteria version and specialist interpretation rules should govern incomplete or conflicting childhood presentations?
- Which aortic measurement conventions and Z-score reference equations should be accepted, and how should incompatible series be represented?
- Which current jurisdiction-specific guidance should supply surveillance intervals, activity recommendations, and intervention-review triggers?
- How should evolving FBN1 classifications update diagnostic confidence while preserving previous interpretations and their dates?
- Which measures of pain, fatigue, visual function, mobility, and participation best capture burden without assuming that every symptom is caused by Marfan syndrome?