Marfan Syndrome
Details of the Concept
Marfan syndrome is an autosomal dominant systemic connective-tissue disorder caused by heterozygous loss-of-function variants in FBN1 (fibrillin-1, chromosome 15q21.1). Its two cardinal features — aortic root aneurysm at the sinuses of Valsalva and ectopia lentis — anchor the diagnostic nosology, and everything else (long-bone overgrowth, pectus deformity, dural ectasia, skin striae, myopia) contributes only as a weighted systemic score. (sources/marfan-ghent-jmg-2010, rating: very high)
The mechanism is a fibrillinopathy rather than a structural weakness in the ordinary sense. Fibrillin-1 microfibrils are the scaffold of elastic fibres, but they also sequester latent TGF-β in the extracellular matrix; when microfibrils are deficient, latent complexes are released and signalling rises. Aortic disease then follows both a mechanical route (wall stress on impaired tissue) and a signalling route (excess TGF-β and angiotensin signalling driving matrix metalloproteinases and elastolysis) — which is why the therapeutic targets are haemodynamic and molecular at once. (sources/marfan-lancet-2005, rating: high; sources/marfan-cv-clingene-2015, rating: high)
Key Facts
Epidemiology and Natural History
The textbook figure is 1 in 5,000 to 1 in 10,000 live births, but every population-based study has found less than that. The gap matters for service planning: the disorder sits at or below the European rare-disease threshold of 1:2,000 everywhere it has been counted. (sources/marfan-ghent-aclingene-2015, rating: high)
| Study population | Prevalence per 100,000 |
|---|---|
| Northern Ireland (Lynas) | 1.5 |
| Denmark, nationwide (Fuchs) | 4.6 |
| Scotland (Gray) | 6.8 |
| Hamburg adults (Rybczynski) | 7.0 |
| Taiwan, national cohort (Chiu) | 10.2 |
| China, schoolchildren (Sun) | 17.2 |
- The spread reflects ascertainment, not biology. Diagnostic criteria have changed across study periods, and under-diagnosis is substantial; the schoolchild screening study found the highest figure, which is the pattern expected if adult clinic-based counts miss mild phenotypes. (sources/marfan-ghent-aclingene-2015)
- A quarter of cases are de novo, so a negative family history carries no weight against a typical phenotype — about 75% of classic Marfan patients do have an affected relative. (sources/marfan-naturerc-2010, rating: medium)
- Penetrance is near-total, expressivity is not. Almost all carriers develop disease, yet phenotypes differ markedly between and within families. (sources/marfan-naturerc-2010)
- Life expectancy is now near normal, but only because of surgery: before prophylactic root replacement the great majority died of cardiovascular causes, at about two-thirds of normal life expectancy. (sources/marfan-lancet-2005)
- Diagnosis is still badly delayed. In a 682-family European survey, the interval from first manifestation to diagnosis was 2 years for half of families and 4.5 years for a quarter; 38% had consulted more than five physicians, 25% had received a wrong diagnosis first, and the delay led to inappropriate treatment in 81%. (sources/marfan-ghent-aclingene-2015)
Pathophysiology
| Step | Molecular detail |
|---|---|
| Gene | FBN1, 65 exons over 235 kb; >1,500 causative variants described; most are private |
| Protein | Fibrillin-1, a 350 kDa glycoprotein; missense variants cluster in EGF-like domains and disrupt cysteine residues or Ca²⁺ binding, promoting proteolysis |
| Matrix | Microfibrils maintain elastic fibres postnatally rather than assembling them; loss produces an abnormal smooth-muscle synthetic repertoire with MMP-2/9 upregulation and elastolysis |
| Signalling | Microfibrils sequester the large latent TGF-β complex (TGF-β + LAP + LTBP); deficiency releases it and raises receptor activation |
| Downstream | Canonical Smad2/3 and non-canonical MAPK/ERK branches; ERK appears to be the dominant contributor to aortic disease |
| Angiotensin | AT1R drives ERK1/2 and is harmful; AT2R inhibits AT1R-mediated ERK1/2 and is protective |
- Haploinsufficiency, not dominant-negative, sets the threshold. A transgenic model carrying a mutant allele plus two normal alleles did not develop the vascular phenotype, and adding a wild-type allele rescued it — the opposite of what a dominant-negative poison polypeptide would do. Dominant-negative effects are contributory rather than decisive. (sources/marfan-lancet-2005)
- TGF-β excess is not confined to the aorta. Alveolar septation failure in the lung, myxomatous change in the mitral valve and dural ectasia all show the same signature, which is why the phenotype is systemic. (sources/marfan-lancet-2005)
- Exons 24–32 predict severity. There is no robust genotype-phenotype correlation overall, but variants in this region tend to produce a more severe phenotype, and neonatal Marfan — the severe end of the spectrum, not a separate category — usually maps here. (sources/marfan-naturerc-2010; sources/marfan-ghent-jmg-2010)
- Elastolysis precedes dilatation. In the mgR/mgR mouse, significant elastic-lamella fragmentation is present throughout the aorta — descending and infrarenal included — before any measurable dilatation, so a normal diameter does not mean normal wall. (sources/marfan-cv-clingene-2015)
- A proteolytic fragment propagates the injury. The elastin-binding-protein fragment GxxPG, released from fibrillin-1, stimulates macrophage chemotaxis and MMP upregulation; neutralising antibodies reduced inflammation and aneurysm size in mice. (sources/marfan-cv-clingene-2015)
- Dilated cardiomyopathy is a primary myocardial disorder, not merely volume overload. Fibrillin-1 in the myocardial matrix transmits force, and its deficiency impairs cardiomyocyte mechanosignalling — an important exception to any blanket anti-TGF-β strategy, since blocking that pathway could worsen the myocardial phenotype while helping the aortic one. (sources/marfan-cv-clingene-2015)
- Cystic medial necrosis is not specific. Fragmentation of the elastic lamina with basophilic ground substance was described by Erdheim in the 1920s and is found in thoracic aortic aneurysm of any cause. (sources/marfan-naturerc-2010)
Clinical Features
| System | Feature | Frequency or detail |
|---|---|---|
| Cardiovascular | Aortic root aneurysm (sinuses of Valsalva) | The defining lesion; present from fetal life and the leading cause of death |
| Mitral valve prolapse | More than half of a paediatric cohort (n=166, mean age 12) | |
| Mitral regurgitation | >25% of those with prolapse progress by adulthood; twice as many women as men | |
| Aortic regurgitation | Late; follows annular stretching by the expanding root | |
| Supraventricular arrhythmia | Associated with mitral disease; prolonged QT described in children | |
| Ocular | Ectopia lentis | ~60%; superotemporal displacement |
| Myopia >3 D, flat cornea, early cataract or glaucoma, retinal detachment | Myopia scores 1 point | |
| Skeletal | Dolichostenomelia, arachnodactyly, wrist and thumb signs | Arm span:height >1.05 |
| Scoliosis, pectus carinatum or excavatum, pes planus, protrusio acetabuli, reduced elbow extension | Each scores on the systemic score | |
| Craniofacial: dolichocephaly, enophthalmos, downslanting fissures, malar hypoplasia, retrognathia | 3 of 5 present scores 1 point | |
| Pulmonary | Spontaneous pneumothorax | 4–15%; apical blebs |
| Restrictive lung disease | From pectus deformity and scoliosis | |
| Skin | Striae atrophicae | ~2/3, at non-weight-bearing sites |
| Inguinal hernia | Common, with increased recurrence after repair | |
| Dura | Lumbosacral dural ectasia | 63–92%; usually asymptomatic; 2 points |
(sources/marfan-lancet-2005 for all frequencies except mitral prolapse, which is sources/marfan-naturerc-2010)
- Three vascular features drive outcome. Maximal aortic diameter is the strongest determinant of dissection; the second is a family history of dissection at a small diameter; growth rate, pregnancy and resistant hypertension follow. (sources/marfan-ghent-jmg-2010; sources/AD-AHA-2022, rating: very high)
- Diameter is not the whole story. Aortic stiffness is an independent risk factor beyond diameter alone, and type B dissection is the initial aortic event in about 10% of patients — sometimes after root replacement. (sources/marfan-cv-clingene-2015; sources/AD-AHA-2022)
- Aortic growth is measurable and slow. In the beta-blocker versus ARB trials, mean root growth was 1–1.5 mm over 3 years and 4–5 mm over 5 years, accelerating with larger diameters; a mean of 0.26 cm/year is often quoted from cohort data, rising to 0.46 cm/year once the root exceeds 6.0 cm. (sources/AD-AHA-2022)
- Abdominal aortic disease follows thoracic repair. Prior thoracic aortic repair is itself a risk factor for abdominal aortic aneurysm in Marfan syndrome, so surveillance continues below the diaphragm. (sources/marfan-cv-clingene-2015)
Diagnosis
Revised Ghent nosology (2010).
The 2010 revision replaced the 1996 major/minor framework across six organ systems with two cardinal features and a weighted score, and gave molecular testing real diagnostic weight. Retrospective comparison showed ~90% concordance with the 1996 criteria; the 10% discordance was deliberate — earlier diagnosis in children with a convincing phenotype, and restraint in adults without cardiovascular risk. (sources/marfan-ghent-jmg-2010)
Without a family history, four routes establish the diagnosis:
- Aortic root Z ≥2 plus ectopia lentis.
- Aortic root Z ≥2 plus a bona fide FBN1 variant.
- Aortic root Z ≥2 plus systemic score ≥7, after excluding features of Shprintzen-Goldberg, Loeys-Dietz and vascular Ehlers-Danlos.
- Ectopia lentis plus an FBN1 variant previously associated with aortic disease in a proband.
With a family history of Marfan syndrome, three routes:
- Ectopia lentis plus family history.
- Systemic score ≥7 plus family history.
- Aortic root Z ≥2 (age ≥20) or Z ≥3 (age <20) plus family history.
The near-misses are defined rather than left ambiguous: ectopia lentis with an FBN1 variant not linked to aortic disease is ectopia lentis syndrome; aortic root Z <2 with systemic score ≥5 (including at least one skeletal feature) is MASS phenotype; mitral valve prolapse with root Z <2 and systemic score <5 is MVPS.
Systemic score — maximum 20 points; ≥7 indicates systemic involvement:
| Feature | Points |
|---|---|
| Wrist and thumb sign | 3 (wrist or thumb alone: 1) |
| Pectus carinatum | 2 (pectus excavatum or chest asymmetry: 1) |
| Hindfoot deformity | 2 (plain pes planus: 1) |
| Spontaneous pneumothorax | 2 |
| Dural ectasia | 2 |
| Protrusio acetabuli | 2 |
| Reduced upper/lower segment ratio and increased arm/height ratio | 1 (US/LS <0.85 white or <0.78 Black adults; arm/height >1.05) |
| Scoliosis (Cobb ≥20°) or thoracolumbar kyphosis | 1 |
| Reduced elbow extension (≤170°) | 1 |
| Three of five facial features | 1 |
| Skin striae | 1 |
| Myopia >3 diopters | 1 |
| Mitral valve prolapse | 1 |
Joint hypermobility, highly arched palate and herniae were removed from the 1996 criteria for lack of specificity. (sources/marfan-ghent-jmg-2010)
What counts as a "bona fide" FBN1 variant is defined explicitly: one shown to segregate in a Marfan family, or a de novo nonsense, frameshift, canonical splice-site, or cysteine-affecting missense variant; other missense variants require segregation plus absence from ≥400 ethnically matched controls. (sources/marfan-ghent-jmg-2010)
Children under 20 are handled by staging rather than by forcing a diagnosis: insufficient systemic features with a root Z <3 and no variant is "non-specific connective tissue disorder" pending follow-up, and a confirmed variant with a root Z <3 is "potential Marfan syndrome". The aortic threshold with a family history rises to Z ≥3, and ectopia lentis syndrome cannot be diagnosed before age 20. (sources/marfan-ghent-jmg-2010)
Pre-test probability and who to investigate.
The "seven-signs" tool assigns 4 points to ectopia lentis, 2 to a family history of Marfan syndrome, and 1 each to previous thoracic aortic surgery, pectus excavatum, wrist-and-thumb sign, previous pneumothorax and skin striae — with ≤1 low, >1–3.5 moderate and >3.5 high pre-test probability. (sources/marfan-ghent-aclingene-2015)
- Referral triggers do not perform equally. In 329 adults referred for suspected Marfan syndrome, confirmation rates were highest for a childhood diagnosis (88%), eye manifestations (83%), family history of Marfan features (52%) and aortic aneurysm or dissection (50%), and lowest for isolated skeletal features (30%), tissue weakness or hypermobility (14%) and non-aortic cardiovascular findings (0%). Tall stature and scoliosis are common reasons for referral and rarely confirm the diagnosis. (sources/marfan-ghent-aclingene-2015)
Imaging.
- Measure the root correctly. Parasternal long axis, at the sinuses of Valsalva, perpendicular to the aortic long axis, taking the largest of at least three measurements. Inner-edge to inner-edge in systole for patients ≤25 years; leading-edge to leading-edge in diastole at all ages, against the Roman 1989 nomograms. (sources/marfan-ghent-jmg-2010)
- Z-scores are the wrong tool at the extremes of body size. The Roman nomograms were not validated above the 95th percentile of height — which describes most Marfan patients — and assuming a linear relationship overestimates the upper limit of normal, so dilatation is under-called. Verify which nomogram the reporting laboratory uses. (sources/marfan-ghent-aclingene-2015)
- A simple paediatric ratio helps. A sinus-of-Valsalva to aortic-annulus ratio ≥1.45 gives sensitivity 0.82 and specificity 1.00 for dilatation in children, though it fails once the annulus itself dilates. (sources/marfan-naturerc-2010)
- Dural ectasia is quantified, not eyeballed. Using the dural sac ratio at each level from L1 to S1, an L3 ratio >0.47 or an S1 ratio >0.57 gives 95% sensitivity and 98% specificity; qualitatively, failure of the sac to taper from L4 to S1 is suggestive. (sources/marfan-naturerc-2010)
Genetic testing and family screening.
- FBN1 is found in up to 97% of patients who meet criteria, but more than 90% of variants are private, so testing is confirmatory rather than screening. It is most useful when clinical criteria are insufficient, for presymptomatic diagnosis in a family with a known variant, and to exclude Loeys-Dietz in an atypical phenotype. (sources/marfan-naturerc-2010; sources/marfan-ghent-jmg-2010)
- Cascade testing is guideline-directed. Genetic testing is recommended for syndromic features, a family history of thoracic aortic disease or early onset, and a positive result triggers gene-based management and cascade testing of relatives; where testing is negative or shows a variant of uncertain significance, first-degree relatives still undergo aortic imaging. (sources/genetic-test-aha-2020, rating: high; sources/AD-AHA-2022)
- A variant of uncertain significance changes nothing. It should not be used to identify at-risk relatives or to guide management. (sources/AD-AHA-2022)
Differential diagnosis.
| Condition | Gene | Discriminating features |
|---|---|---|
| entities/Loeys-Dietz-Syndrome | TGFBR1/2, TGFB2/3, SMAD2/3 | Hypertelorism, bifid uvula or cleft palate, arterial tortuosity, craniosynostosis, diffuse arterial aneurysm; dissection at smaller diameters |
| Vascular Ehlers-Danlos | COL3A1 | Translucent skin, easy bruising, dystrophic scarring, hollow-organ rupture; medium arteries rather than the root |
| Homocystinuria | CBS | Lens dislocates downward (Marfan: upward and temporal), intellectual disability, thrombosis, no aortic enlargement; excluded by plasma amino acids |
| MASS phenotype | FBN1 possible | Mitral prolapse with mild, non-progressive root dilatation plus skeletal and skin features |
| Ectopia lentis syndrome | FBN1, LTBP2, ADAMTSL4 | Lens dislocation with a normal root; lifelong cardiovascular surveillance still required |
| Familial non-syndromic TAAD | ACTA2, MYH11, TGFBR2, TGFBR1, MYLK, PRKG1 | No Marfanoid habitus; ACTA2 adds livedo reticularis, iris flocculi, moyamoya and premature coronary disease |
| entities/Bicuspid-Aortic-Valve | NOTCH1 and others | Dilatation above the sinotubular junction; no systemic features |
| Shprintzen-Goldberg syndrome | SKI | Craniosynostosis, marfanoid habitus, intellectual disability; originally misattributed to FBN1 |
| entities/Aneurysm-Osteoarthritis-Syndrome | SMAD3 | Aneurysm, arterial tortuosity, early osteoarthritis, craniofacial features |
| Weill-Marchesani, Beals, arterial tortuosity syndrome | FBN1/ADAMTS10, FBN2, SLC2A10 | Microspherophakia and short stature; crumpled ears and contractures; generalised tortuosity |
(sources/marfan-ghent-jmg-2010 for the discriminating features; sources/marfan-cv-clingene-2015 for the SKI and SMAD3 reclassifications)
Management
Medical therapy.
- A beta-blocker or an ARB, at maximally tolerated dose, is Class I, Level A — the only Class I/A recommendation anywhere in the aortopathy medical-therapy section, and the two agents are equivalent. Using both together is reasonable (IIa/A). (sources/AD-AHA-2022; sources/AD-PAD-ESC-2024, rating: very high)
- Equivalence is an evidence-based finding, not a default. The Pediatric Heart Network trial randomised children and young adults to atenolol or losartan double-blind and found no difference in aortic root growth rate or adverse effects, refuting the superiority suggested by the fibrillin-1 mouse model and by earlier small trials. (sources/marfan-ghent-aclingene-2015)
- Titrate to effect, not to a fixed dose. Beta-blockers are titrated to a heart rate below 100 bpm after submaximal exercise; the dose is not predicted by body weight. (sources/marfan-ghent-jmg-2010)
- Calcium-channel blockers are the wrong second-line choice here. Verapamil has been used where beta-blockade fails, but calcium-channel blockers have shown increased aortic risk in a mouse model and in retrospective case-control data, so alternatives are preferred for hypertension. (sources/marfan-cv-clingene-2015; sources/AD-PAD-ESC-2024)
- Medical therapy slows growth; it does not stop it. Imaging continues regardless of treatment. (sources/marfan-lancet-2005)
- Circulating fibrillin-1 fragments correlate with aneurysm and dissection risk and are being developed as a biomarker to complement diameter. (sources/marfan-cv-clingene-2015)
Surveillance.
| Situation | Imaging |
|---|---|
| At diagnosis | TTE of root and ascending aorta, repeated at 6 months to establish growth rate |
| Root <45 mm, no risk factors | TTE at least annually |
| Root <45 mm with risk factors | TTE at least every 6 months |
| Root ≥45 mm | TTE at least every 6–12 months |
| Root or ascending not well seen (pectus, lung disease) | CT or MRI of the thoracic aorta |
| Whole aorta and peripheral arteries at first evaluation | CMR (preferred) or CT plus duplex, then every 3–5 years if stable |
| After root replacement | Thoracic imaging annually, then every 2 years if unchanged; abdominal imaging every 3–5 years |
Risk factors here are a root of 40–45 mm with a family history of dissection below 50 mm, resistant hypertension, and growth ≥3 mm/year. (sources/AD-AHA-2022; sources/AD-PAD-ESC-2024)
- MRI over CT for serial imaging, to limit cumulative radiation in a population scanned for life. (sources/marfan-cv-clingene-2015)
Surgery.
| Indication | Threshold | Class |
|---|---|---|
| Root or ascending, no additional risk factors | ≥50 mm | I/B |
| Root with an additional risk factor | ≥45 mm | IIa/C |
| Area/height ratio | ≥10 cm²/m | IIa |
| Ascending, arch, descending or abdominal aneurysm | ≥50 mm | IIa/C |
| Valve-sparing root replacement | Where valve anatomy allows and the surgeon has specific expertise | I/B |
| Growth prompting earlier surgery | ≥3 mm/year in adults (AHA: ≥5 mm in one year, or ≥3 mm/year over two years) | — |
(sources/AD-PAD-ESC-2024; sources/AD-AHA-2022)
- The valve is preserved by default. Valve-sparing root replacement avoids lifelong anticoagulation and is preferred in eligible patients — especially women planning pregnancy — and short-term operative mortality is comparable to composite graft repair, though no randomised comparison exists. (sources/marfan-lancet-2005)
- Open repair is preferred over endovascular repair in Marfan syndrome; endovascular repair may be considered only in selected emergencies or at high-expertise centres, and for type B disease the weakened adjacent aorta may not tolerate radial stent force. (sources/AD-PAD-ESC-2024; sources/marfan-ghent-jmg-2010)
- Type B dissection accounts for about 10% of aortic events and may occur below surgical thresholds or after root replacement. Indications for intervention are intractable pain, malperfusion, diameter >55 mm or rapid growth. (sources/marfan-ghent-jmg-2010; sources/AD-AHA-2022)
- Mitral valve repair is preferred over replacement for severe regurgitation with symptoms or progressive LV dilatation, ideally at the time of root surgery. (sources/marfan-ghent-jmg-2010)
Pregnancy.
- Risk stratification is by diameter. Marfan syndrome without aortic dilatation is mWHO Class II (5.7–10.5% maternal cardiac event rate); severe aortic dilatation above 45 mm is Class IV, where pregnancy is not recommended. (sources/cv-pregnancy-esc-2018, rating: very high)
- Prophylactic root replacement before conception is Class I above 45 mm and may be considered at 40–45 mm (IIb). Whole-aorta imaging before pregnancy is Class I. (sources/AD-PAD-ESC-2024)
- The beta-blocker continues through pregnancy and postpartum (I); ARBs are contraindicated (III). This is the one setting in which the standard medical regimen must be changed rather than continued. (sources/AD-PAD-ESC-2024)
- Delivery: vaginal if the aortic diameter is <40 mm; caesarean reasonable at ≥45 mm. Aortic complications cluster in the third trimester and early puerperium. (sources/AD-AHA-2022; sources/cv-pregnancy-esc-2018)
- Type B dissection risk persists after root replacement and may occur without prior dilatation; patients should be counselled accordingly. (sources/AD-PAD-ESC-2024)
Activity.
- Competitive and high-intensity strength sport is out. In heritable thoracic aortic disease the risk of high-intensity strength work likely outweighs benefit even at normal aortic dimensions, and outweighs benefit once dilatation is present; collision sports, burst exertion and Valsalva-heavy isometric work are avoided. (sources/competitive-sports-aha-2025, rating: very high; sources/AD-AHA-2022)
- Moderate aerobic exercise is recommended, not merely permitted (I/C), individualised to aortic diameter, family history and baseline fitness; 30–60 minutes on 3–4 days per week is reasonable where blood pressure is controlled. In children and young adults, higher daily step counts have been associated with slower root growth. (sources/AD-PAD-ESC-2024; sources/AD-AHA-2022)
- Cardiac rehabilitation after dissection or aortic surgery should be considered (IIa/B) for physical and psychological recovery. (sources/AD-PAD-ESC-2024)
Contradictions / Open Questions
- The 75% mitral prolapse figure is a misattribution that has propagated. The 75% in the primary literature refers to the proportion of classic Marfan patients with an affected relative; mitral prolapse was found in "more than half" of a paediatric cohort of 166. Quoting 75% for prolapse inflates the valve phenotype and displaces the family-history statistic. (sources/marfan-naturerc-2010, rating: medium; sources/marfan-lancet-2005, rating: high)
- Textbook prevalence exceeds every measured prevalence. The 1:5,000–1:10,000 figure is repeated in guidelines while population studies find 1.5–17.2 per 100,000 — at or below the 1:2,000 rare-disease threshold. Either the denominator is wrong or a large undiagnosed population exists; the two possibilities imply very different screening policies. (sources/marfan-ghent-aclingene-2015, rating: high; sources/AD-PAD-ESC-2024, rating: very high)
- The trial evidence is paediatric. The trial that settled beta-blocker versus ARB enrolled children and young adults, and the adult recommendation is extrapolation from it plus older adult observational and open-label data. The equivalence of the two drug classes in a 55-year-old with a 48 mm root is assumed rather than demonstrated. (sources/marfan-ghent-aclingene-2015; sources/AD-AHA-2022)
- Haploinsufficiency versus dominant-negative remains unresolved. Mouse models support a threshold, dosage-dependent mechanism, but the authors concede dominant-negative effects contribute; how the two interact, and whether they predict different aortic risk, is unknown. (sources/marfan-lancet-2005)
- The human TGF-β story did not translate as predicted. Losartan prevented aneurysm in fibrillin-1-deficient mice and looked superior in early human work, yet the definitive randomised trial found it equivalent to atenolol. Either the mouse model overstates the pathway's centrality or the drug does not engage it in humans at tolerated doses. (sources/marfan-ghent-aclingene-2015)
- Canonical versus non-canonical pathway primacy may be stage-dependent. ERK appears to be the major contributor in mild disease models, but losartan normalised ERK without normalising Smad signalling in severe disease — so the correct molecular target may differ by disease stage and tissue, which a single-agent strategy cannot exploit. (sources/marfan-cv-clingene-2015)
- Anti-TGF-β therapy may be actively harmful to the myocardium. Fibrillin-1 deficiency causes a primary dilated cardiomyopathy through impaired mechanosignalling, so broad pathway blockade could trade an aortic benefit for a myocardial cost. (sources/marfan-cv-clingene-2015)
- The nosology has no reference standard. No single feature or combination carries a likelihood ratio above 10 or below 0.1, so sensitivity, specificity and accuracy cannot be calculated for any version of the Ghent criteria, and diagnosis remains a clinical judgement. The 90% concordance between the 1996 and 2010 versions is a consistency measure, not a validation. (sources/marfan-ghent-aclingene-2015)
- Valve-sparing versus composite graft has never been randomised. Short-term operative mortality is comparable and valve-sparing is now preferred in eligible patients, but the long-term reintervention rate is the outcome that matters and it remains unmeasured in a controlled comparison. (sources/marfan-lancet-2005)
- Nothing prevents dissection entirely. Every approved therapy slows dilatation; dissections still occur below thresholds, particularly type B and after root replacement. The threshold-based model of risk is a population approximation being applied to individuals. (sources/AD-PAD-ESC-2024)
Connections
- Gene and mechanism: entities/FBN1 — the causative gene · concepts/Heritable-Thoracic-Aortic-Disease — the category this belongs to
- Aortopathy differential: entities/Loeys-Dietz-Syndrome · entities/Aneurysm-Osteoarthritis-Syndrome · entities/Bicuspid-Aortic-Valve
- Aortic disease: concepts/Thoracic-Aortic-Aneurysm · concepts/Acute-Aortic-Syndrome · concepts/Abdominal-Aortic-Aneurysm
- Cardiac and valvular: entities/Mitral-Valve-Prolapse · concepts/Aortic-Regurgitation · concepts/Aortic-Stenosis
- Diagnosis and genetics: concepts/Genetic-Testing-in-Cardiomyopathy · concepts/ClinGen-Gene-Disease-Validity
- Therapy, pregnancy and activity: concepts/Beta-Blockers · concepts/Prepregnancy-Cardiovascular-Health