Marfan Syndrome Flashcards
What is the inheritence of Marfan syndrome?
Autosomal dominant
Which type of systemic disease?
Connective tissue disorder
Marfan syndrome: chromosome and gene
Chromosome 15
Gene: Fibrillin-1
Other disorders associated with Fibrillin-1 mutation
Familial Ectopia lentis
Weill Marchesani syndrome
Sex/gender of Marfan syndrome
both male and female are affected
What is the carrier state?
NO carrier state
one mutated gene (heterozygote) will manifest disease
Can Marfan syndrome skip a generation?
NO
normally appears in every generation
Ratio of new mutation
Among the affected person, 25% are first affected/new mutation
Arm span to body height ratio in Marfan syndrome
>1.05
Normal: <1.05
Stature of Marfan syndrome
Tall stature with disproportionately long limbs (= dolichostenomelia)
Intelligence in Marfan syndrome
Usually normal
Eye features of Marfan syndrome
Ectopia lentis (superotemporal/upward lens dislocation)
Blue sclera
Myopia
Peripheral retinal degeneration >>> retinal detachment
Head-neck features of Marfan syndrome
High arched palate ( & narrow)
Crowded teeth
High-arched neck
Limb features of Marfan syndrome
Arachnodactyly
Steinberg sign positive
Walker-Murdoch sign positive
Joint laxity
Pes planus in foot
Arachnodactyly
Also called ‘spider finger’
Arachnid = Spider
Fingers are abnormally long, slender, curved liked spider legs +
all or few fingers can be bent backwards of 180 degree
What are the specific signs of Marfan’s syndrome?
Steinberg sign positive
Walker-Murdoch sign positive
Steinberg sign
Fold your thumb >> then close your fist >> if thumb tip extends beyond the palm of hand >> Steinberg sign positive
Walker-Murdoch sign
Grip your wrist with your opposite hand >>> if thumb and fifth finger of hand overlap with each other >>> positive Walker-Murdoch sign
Radiological features of Marfan syndrome
Protrusio acetabulae
Dural ectasia in spinal MRI
Trunk features in Marfan syndrome
Pectus Excavatum or Carinatum
Scoliosis >20degree
Cardiac defects in Marfan syndrome
1. Dilation of the aortic root sinuses (90%cases of Marfan) >>> leads to Aortic regurgitation
2. Mitral valve prolapse (MVP) (75%cases of Marfan)
3. Aortic dissection
The most common cardiac defect in Marfan syndrome
Aortic root dilation >>> leading to >>> Aortic regurgitation
The second common cardiac defect in Marfan syndrome
Mitral valve prolapse (MVP) in 75% cases
often AR and MVP are present together
Murmur of MVP (Mitral valve prolapse)
Late systolic murmur
Pulmonary defect in Marfan syndrome
Repeated spontaneous pneumothoraces
Apical blebs on chest radiograph
Skin feature in Marfan syndrome
Striae
Blood defect in Marfan syndrome
Increased risk of thromboembolic disorder
Similarity between marfan syndrom and homocystinuria
Marfan syndrome may present with high homocystine level (homocystinuria)
Homocystinuria may present with marfanoid habitus (e.g. arachnodactyly etc.)
Difference between Marfan syndrome and homocystinuria
Marfan syndrome: Autosomal dominant
Homocystinuria: Autosomal recessive
Marfan syndrome: upward ectopia lentis
Homocystinuria: downward ectopia lentis
Marfan syndrome is diagnosed by-?
Modified Ghent criteria
Why did Ghent criteria need to be modified?
Due to emerging spectrum of mutations in fibrilin-1 associated disorders (other than Marfan syndrome)
What is the significance of new modified Ghent criteria?
It placed greater weight on >>>
- Cardiac features
- Aortic dilatation
- Ectopia lentis
How ‘systemic score’ is calculated to be used in modified Ghent criteria?
A systemic score is calculated, according to presence of >>>
- Musculoskeletal findings
- Radiological findings
- Skin findings
>> weighted according to their diagnostic specificity
In patient without family history >> modified Ghent criteria to diagnose Marfan syndrome?
Any of the following four conditions >>> Diagnosis of Marfan syndrome:
- Aortic dilatation (Z score greater than or equalling 2) + Ectopia lentis
- Aortic dilatation (Z score greater than or equalling 2) + Fibrillin-1 gene mutation
- Aortic dilatation + systemic score greater than or equalling 7
- Ectopia lentis and Fibrilin-1 mutation
*** This Fibrillin-1 gene mutation should be known to be associated with Marfan syndrome, not other disorders
In patient with family history >> modified Ghent criteria to diagnose Marfan syndrome?
Family history in first degree relatives = parent, siblings, child
If presence any of >>
- Family history + Aortic dilataion
- Family history + Ectopia lentis
- Family history + Systemic score greater than or equalling 7
>>>>> Dx of Marfan syndrome
Treatment of Marfan syndrome
ACE inhibitors
Beta blockers
If lens is fully dislocated from pupil aperture >>>>> Aphakic lens
Monitoring in Marfan syndrome
Regular echocardiography
Life expectancy
Around 40 to 50years
If undiagnosed >>> high risk of death in 30s to 40s
Main cause of death in Marfan syndrome
Aortic dissection (AD) & other heart defects
