The Classic Connective Tissue Disorder
Ghent Criteria
Critical Must-Knows
- FBN1 Gene: Fibrillin-1 mutation.
- Aortic Root: Annual echo screening essential.
- Scoliosis: Common, may be progressive.
- Protrusio Acetabuli: Characteristic finding.
- Dural Ectasia: Expand the dural sac.
Clinical Pearls
- "FBN1 mutation
- "Aortic root is main mortality cause
- "Scoliosis screening needed
- "Protrusio is characteristic
Clinical Imaging
Imaging Gallery
Cardiac Monitoring
Aortic root dilation and dissection are the main causes of death in Marfan Syndrome.
- Annual echocardiogram is MANDATORY.
- Beta-blockers reduce aortic root growth.
- Avoid strenuous/contact sports.
- Pre-operative cardiac clearance for scoliosis surgery.
Skeletal Features in Marfan
| Feature | Description | Management |
|---|---|---|
| 30-50% | Bracing, surgery if progressive | |
| Excavatum or Carinatum | Surgical repair if severe | |
| Medial protrusion of acetabulum | Usually observation | |
| Flat feet, hypermobile | Orthotics |
MARFSMarfan Features
| M | Marfanoid habitus Tall, thin, arachnodactyly |
| A | Aortic root Dilation, dissection |
| R | Retinal (lens) Dislocation upwards |
| F | FBN1 Gene mutation |
| S | Scoliosis Common orthopaedic issue |
| M | Marfanoid habitus Tall, thin, arachnodactyly | F | FBN1 Gene mutation |
| A | Aortic root Dilation, dissection | S | Scoliosis Common orthopaedic issue |
| R | Retinal (lens) Dislocation upwards |
Hook:MARFS - Marfanoid, Aortic, Retinal, FBN1, Scoliosis.
PPPSSkeletal Features
| P | Pectus Excavatum or carinatum |
| P | Protrusio Acetabuli |
| P | Pes planus Flat feet |
| S | Scoliosis 30-50% |
| P | Pectus Excavatum or carinatum | P | Pes planus Flat feet |
| P | Protrusio Acetabuli | S | Scoliosis 30-50% |
Hook:PPPS - Pectus, Protrusio, Pes planus, Scoliosis.
GHENTGhent Criteria
| G | Genetics FBN1 mutation |
| H | Heart Aortic root dilation |
| E | Eyes Ectopia lentis (lens dislocation) |
| N | Numbers Systemic score ≥7 |
| T | Tests Dural ectasia on MRI |
| G | Genetics FBN1 mutation | N | Numbers Systemic score ≥7 |
| H | Heart Aortic root dilation | T | Tests Dural ectasia on MRI |
| E | Eyes Ectopia lentis (lens dislocation) |
Hook:GHENT criteria - Genetics, Heart, Eyes, Numbers, Tests.
Overview/Epidemiology
Marfan Syndrome is a connective tissue disorder.
- Genetics: Autosomal dominant. FBN1 (Fibrillin-1) gene on chromosome 15.
- Incidence: 1 in 5,000-10,000.
- Pathophysiology: Defective fibrillin leads to abnormal elastic fibers and increased TGF-β signaling.
- Diagnosis: Ghent criteria (revised 2010).
Pathophysiology and Mechanisms
Connective Tissue Abnormalities
- Fibrillin is a component of elastic fibers.
- Abnormal elastic fibers affect aorta, ligaments, lens zonules.
- Increased TGF-β signaling contributes to aortic disease.
Why Scoliosis Develops
- Ligamentous laxity + abnormal connective tissue.
- Curves may resemble idiopathic scoliosis but can be more severe.
Classification Systems
Ghent Criteria (Revised 2010)
Major Features:
- Aortic root dilation (Z-score ≥2) or dissection.
- Ectopia lentis (lens dislocation).
- FBN1 mutation.
- Systemic score ≥7 (skeletal features).
- Dural ectasia.
Diagnosis: 2 major features from different systems OR FBN1 + 1 major.
Clinical Assessment
History:
- Family history.
- Cardiac symptoms (palpitations, chest pain).
- Visual symptoms.
- Musculoskeletal symptoms.
Physical Exam:
- General: Tall, thin, arm span greater than height.
- Arachnodactyly: Long fingers. Walker-Murdoch (thumb overlaps fifth finger around wrist). Steinberg (thumb extends beyond ulnar border).
- Pectus: Excavatum or carinatum.
- Spine: Scoliosis.
- Hips: Protrusio (limited IR).
- Feet: Pes planus, hindfoot valgus.
- Eyes: Slit lamp for lens dislocation.
Investigations
Genetic Testing:
- FBN1 mutation: Confirmatory.
Cardiac:
- Echocardiogram: Aortic root measurement. Annual.
Ophthalmology:
- Slit lamp: Lens dislocation.
Imaging:
- Spine X-ray: Scoliosis.
- Pelvis X-ray: Protrusio acetabuli.
- MRI Spine: Dural ectasia.
Management Algorithm
Cardiac Management
- Annual Echo: Monitor aortic root.
- Beta-Blockers: Reduce aortic root growth rate.
- Losartan: May also help (TGF-β blocker).
- Surgery: Aortic root replacement if dilated.
- Activity Restriction: No contact sports, strenuous activity.
Surgical Techniques
Posterior Spinal Fusion
Indications: Progressive scoliosis greater than 40-50 degrees.
Pre-op: Cardiac clearance. Echo. Avoid hypotension.
Technique: Standard posterior fusion. Curves often longer than idiopathic.
Considerations: Dural ectasia may cause CSF leak. Blood pressure management critical.
Complications
| Complication | Context | Management |
|---|---|---|
| Aortic Dissection | Perioperative | Careful BP control |
| Dural Ectasia | Spine surgery | CSF leak risk |
| Hardware Failure | Weak bone/tissue | Monitor |
Postoperative Care
- Cardiac Monitoring: Blood pressure control.
- Standard Spine Protocol: Mobilization, physiotherapy.
Outcomes/Prognosis
- Life Expectancy: Reduced (median 40-50 years historically). Improved with aortic monitoring and surgery.
- Orthopaedic: Scoliosis surgery outcomes similar to idiopathic.
Controversies & Areas of Uncertainty
- Losartan vs beta-blockade. The Pediatric Heart Network trial (Lacro 2014) found no significant difference between losartan and atenolol for aortic-root growth, and subsequent meta-analyses suggest the two are broadly comparable. Whether combination therapy or angiotensin-receptor blockade adds benefit over beta-blockade alone remains unsettled.
- Optimal aortic-root replacement threshold. The 5.0 cm threshold is pragmatic, not absolute; family history of early dissection, rapid growth (over 3 to 5 mm/year), and planned pregnancy all argue for earlier surgery, while the relative merits of valve-sparing versus composite root replacement are debated.
- Prophylactic surgery for protrusio acetabuli. Older recommendations for triradiate closure in growing children are largely abandoned; Sponseller's data show most protrusio is well tolerated, so intervention is now reserved for genuinely symptomatic or rapidly progressive cases.
- Defining dural ectasia. There is no universally accepted radiographic cut-off; differing dural-sac-ratio thresholds affect reported prevalence and its weight within the Ghent systemic score.
- Fusion levels and approach in syndromic scoliosis. Curve length, kyphosis, pelvic obliquity, and bone fragility complicate level selection; the shift to posterior-only constructs is clear, but distal fusion levels and the role of pelvic fixation remain individualised.
Evidence Base
- International expert panel re-weighted criteria toward cardiovascular disease
- Aortic root aneurysm and ectopia lentis are now the two cardinal features; together they are sufficient for diagnosis when there is no family history
- New weighted systemic score (threshold of 7 or more) and greater emphasis on FBN1 testing; molecular confirmation possible in over 95 percent
- Randomised trial, 608 children and young adults with aortic-root z-score over 3.0
- No significant difference in rate of aortic-root z-score change between losartan and atenolol over 3 years (P=0.08)
- No difference in aortic-root surgery, dissection, or death between groups
- Cross-sectional study, 173 patients (346 hips) with Marfan syndrome
- Prevalence of protrusio 16 to 27 percent depending on the radiographic criterion; rises through the first two decades then plateaus
- Only a slight reduction in hip range of motion and no clinically meaningful loss of Iowa hip score
- Prospective 10-year cohort; 45 of 46 Marfan patients had dural ectasia at follow-up
- Dural ectasia may first appear or worsen during adulthood; anterior sacral meningocoele present in roughly half
- Proposed dural-sac-ratio cut-off at S1 raised to 0.64 for diagnosis
- National database, 314 (1,410 weighted) Marfan patients undergoing spinal fusion 2003 to 2014
- Posterior spinal fusion rose from 67 percent to 92 percent of cases
- Marfan patients had higher neurologic complications than matched non-Marfan controls (2.4 vs 0.79 percent)
- Matched cohort, 20 Marfan vs 40 adolescent idiopathic scoliosis patients after posterior spinal fusion
- Marfan patients used more inpatient opioid (4.9 vs 2.1 mg/kg morphine-equivalents) despite similar pain scores
- Marfan was the only independent predictor of an outpatient opioid request (odds ratio 4.1)
Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scoliosis in Marfan
"15-year-old male with known Marfan Syndrome. Scoliosis of 45 degrees. Aortic root is 4.2cm on recent echo."
This patient has progressive scoliosis requiring surgery. However, the **aortic root is mildly dilated** (normal less than 4.0cm in adults). Pre-operatively, I would obtain **cardiology clearance** with updated echo. I would ensure **blood pressure is well controlled** intraoperatively (avoid hypotension and hypertension). Proceed with **posterior spinal fusion**. Be aware of potential **dural ectasia** (CSF leak risk) and weaker tissues.
Diagnosis of Marfan
"How do you diagnose Marfan Syndrome?"
Diagnosis is based on the **revised Ghent criteria (2010)**. Key features: **Aortic root dilation** (Z-score ≥2), **ectopia lentis** (lens dislocation), **FBN1 mutation**, and **systemic score ≥7** (skeletal features). Diagnosis requires either aortic root + FBN1, OR aortic root + ectopia lentis, OR FBN1 + systemic score ≥7.
Protrusio Acetabuli
"X-ray shows protrusio acetabuli. What is this and how do you manage?"
**Protrusio acetabuli** is medial protrusion of the acetabulum into the pelvis. It is characteristic of Marfan Syndrome. On X-ray, the femoral head protrudes medial to the ilioischial line. Management is usually **observation** as it rarely causes symptoms in youth. In skeletally immature patients with severe progressive protrusio, **triradiate cartilage closure** can be considered. In adults, it may complicate hip arthroplasty.
MCQ Practice Points
Genetics MCQ
Q: What gene is mutated in Marfan Syndrome? A: FBN1 (Fibrillin-1) on chromosome 15.
Cardiac MCQ
Q: What is the main cause of death in Marfan? A: Aortic dissection/rupture.
Orthopaedic MCQ
Q: What hip finding is characteristic of Marfan? A: Protrusio acetabuli.
Eye MCQ
Q: In which direction does the lens dislocate in Marfan? A: Superiorly (upward). Compare to Homocystinuria where it dislocates inferiorly.
Surgical Pearl
Q: What must be done before scoliosis surgery in Marfan? A: Pre-op cardiac clearance with echo is MANDATORY. Watch for dural ectasia (CSF leak risk), curves often longer than idiopathic, and blood pressure control is critical.
Diagnostic Pearl
Q: What are the Walker-Murdoch and Steinberg signs? A: Walker-Murdoch: Thumb overlaps fifth finger when grasping wrist. Steinberg: Thumb extends beyond ulnar border of closed fist. Both indicate arachnodactyly.
Guidelines, Registries & Global Practice
Global epidemiology. Prevalence is approximately 1 in 5,000 worldwide with no clear ethnic or geographic predilection. Inheritance is autosomal dominant with high penetrance but markedly variable expressivity; roughly 25 percent of cases arise from de novo FBN1 mutations and so present without a family history.
Side-by-side guidelines:
| Body / Region | Position |
|---|---|
| 2010 Revised Ghent nosology (international) | Diagnostic standard worldwide; aortic root and ectopia lentis are cardinal; systemic score of 7 or more |
| ACC/AHA (US) aortic disease | Annual imaging of aortic root; elective root replacement at approximately 5.0 cm (lower with family history of dissection, rapid growth, or pregnancy) |
| ESC (Europe) aortic / Marfan | Similar surveillance; root surgery typically at 5.0 cm, individualised; valve-sparing root replacement favoured in expert centres |
| AO / spine deformity (international) | Posterior spinal fusion is the dominant approach; pre-operative MRI to define dural ectasia; cardiac clearance mandatory |
Surgical orthopaedic thresholds (broadly concordant globally). Brace curves of 25 to 40 degrees in the growing child; operate on curves over 40 to 50 degrees, which progress faster and respond less to bracing than idiopathic curves. Observe asymptomatic protrusio acetabuli.
Registry and resource notes. No dedicated Marfan implant registry exists; arthroplasty data are sparse because protrusio rarely requires replacement before late adulthood. National Marfan patient organisations (for example The Marfan Foundation in the US, the Marfan Trust in the UK, and equivalent bodies in many countries) coordinate multidisciplinary clinics.
High- vs limited-resource practice. In well-resourced settings, lifelong echocardiographic (and cross-sectional CT/MRI) aortic surveillance, FBN1 sequencing, valve-sparing root replacement, and neuromonitored spinal fusion are standard. Where genetic testing and advanced imaging are limited, diagnosis leans on the clinical Ghent features and echocardiography; the priority everywhere is recognising aortic risk, restricting high-intensity isometric and contact sport, and arranging cardiac assessment before any major orthopaedic surgery.
MARFAN SYNDROME
Clinical summary
GENETICS
- •FBN1 Mutation
- •Chromosome 15
- •Autosomal Dominant
- •Fibrillin-1 defect
CARDIAC
- •Aortic root dilation
- •Annual echo
- •Beta-blockers
- •Main mortality cause
SKELETAL
- •Scoliosis 30-50%
- •Protrusio acetabuli
- •Pectus
- •Pes planus
DIAGNOSIS
- •Ghent criteria
- •Aortic root + FBN1
- •Systemic score ≥7
- •Ectopia lentis
CLINICAL SIGNS
- •Walker-Murdoch sign
- •Steinberg sign
- •Arm span exceeds height
- •Arachnodactyly
SURGERY PEARLS
- •Cardiac clearance first
- •Dural ectasia risk
- •BP control critical
- •Curves often longer
Self-Assessment Quiz
Differential Diagnosis
Marfan-like Syndromes:
| Condition | Gene | Key Differentiator |
|---|---|---|
| Marfan Syndrome | FBN1 | Aortic root dilation, lens UP |
| Loeys-Dietz Syndrome | TGFBR1/2 | Bifid uvula, hypertelorism |
| Homocystinuria | CBS | Lens DOWN, thrombosis, cognitive issues |
| Ehlers-Danlos (Vascular) | COL3A1 | Thin skin, arterial rupture |
| Stickler Syndrome | COL2A1 | Flat face, hearing loss, retinal detachment |
| Beals Syndrome | FBN2 | Crumpled ears, camptodactyly |
Key Distinguishing Features:
- Lens dislocation direction: Marfan UP, Homocystinuria DOWN
- Cognitive function: Normal in Marfan, impaired in Homocystinuria
- Uvula: Normal in Marfan, bifid in Loeys-Dietz
- Gene: FBN1 for Marfan, FBN2 for Beals