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Marfan’s Syndrome

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Marfan's Syndrome
Rebecca L. Carl
Basics
Description
  • An autosomal dominant genetic disorder of connective tissue affecting primarily the musculoskeletal system, the cardiovascular system, and the eye
  • System(s) affected: Musculoskeletal, cardiovascular, ocular, skin/integument, endocrine/metabolic, pulmonary
  • Genetics: Autosomal dominant with high penetrance; 15–25% spontaneous mutation
  • Incidence/prevalence in U.S.: 1/5,000 to 1/15,000
  • Predominant age: Genetic condition. Generally, clinical manifestations become apparent during late childhood or adolescence. There is a more severe neonatal form of this condition; affected individuals are generally diagnosed in the newborn period.
  • Predominant gender: No gender, ethnic, or racial predilection
Risk Factors
Advanced paternal age gives rise to a slightly increased risk only in cases that are not clearly familial.
General Prevention
No prenatal diagnosis yet available, but presymptomatic diagnosis may be possible at research centers using linkage analysis techniques.
Etiology
Genetic: ∼75% of affected individuals have an affected parent; the remainder have a spontaneous mutation in the fibrillin 1 (FBN-1) gene.
Diagnosis
  • Genetic testing, looking for mutations in the FBN-1 gene, is available. Mutations can be identified in ∼90% of affected individuals.
  • The mainstay of diagnosis is clinical evaluation and application of established diagnostic criteria. These criteria, now known as the Ghent nosology, were revised most recently by De Paepe and colleagues in 1996.
  • Individuals who have a 1st-degree relative with the diagnosis of Marfan syndrome or documented FBN-1 mutation must have a major manifestation in one organ system with involvement of one other system.
  • Individuals with no significant family history or genetic diagnosis must have major manifestations involving 2 organ systems with involvement of an additional system.
  • Echocardiography, spine radiographs, and slit-lamp examination may be helpful in making the diagnosis.
Physical Exam
  • Musculoskeletal:
    • Major criteria:
      • Pectus carinatum
      • Pectus excavatum requiring surgery
      • Upper-segment-to-lower-segment ratio of >1.05
      • Positive thumb sign (thumb can protrude from ulnar side of a clenched fist) and wrist sign (thumb and 5th finger can encircle wrist and overlap)
      • Elbow hyperextension
      • Pes planovalgus with medial displacement of the medial malleolus
      • Protrusio acetabulae on radiographs
      • Scoliosis of >20 degrees or spondylolisthesis
    • Minor criteria:
      • Pectus excavatum
      • Joint hypermobility
      • High arched palate with crowding of teeth
      • Facial appearance
  • Cardiovascular:
    • Major criteria:
      • Aortic root dilatation
      • Dissection of the ascending aorta
    • Minor criteria:
      • Mitral valve prolapse
      • Dilatation of the main pulmonary aorta (age <40)
      • Calcification of the mitral valve annulus (age <40)
      • Dilatation or dissection of the descending or abdominal aorta (age <50)
  • Ocular:
    • Major criterion: Ectopia lentis (lens subluxation)
    • Minor criteria:
      • Flat cornea
      • Decreased miosis owing to hypoplastic iris or ciliary muscles
  • Pulmonary (minor criteria only):
    • Spontaneous pneumothorax
    • Apical blebs
  • Skin/integument (minor criteria only):
    • Striae
    • Recurrent hernia or hernia at an incision site
  • Dura (major criterion only): Lumbosacral dural ectasia
Diagnostic Tests & Interpretation
Lab
  • Genetic testing to look for FBN-1 mutation
  • Drugs that may alter lab results: N/A
  • Disorders that may alter lab results: N/A
Imaging
  • Plain radiographs of the spine are useful prior to skeletal maturity to detect and quantify scoliosis.
  • Initial diagnostic echocardiogram, followed by serial screening echocardiograms, is recommended beginning in adolescence to look for dilatation of the aorta and valvular changes.
Pathological Findings
  • Cystic medial necrosis of the aorta
  • Myxomatous degeneration of the cardiac valves
Differential Diagnosis
  • Homocystinuria
  • Marfanoid habitus
  • Marfanoid skeletal and skin features (MASS) phenotype
  • Ehlers-Danlos syndrome
  • Beal syndrome (congenital contractural arachnodactyly)
  • Loeys-Dietz syndrome

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Treatment
  • Long-term treatment
  • Acute treatment: Outpatient
Medication
First Line
  • No specific medical therapy is available. Medications may be used to treat manifestations of Marfan syndrome.
  • Beta blockers have been used to slow progression of aortic root dilatation.
  • ACE inhibitors and calcium channel blockers have been used in patients who don't tolerate or fail to respond to beta blockers.
  • Recent studies using animal models suggest that angiotensin II receptor blockers may be effective in slowing aortic root dilatation as well; clinical studies are currently in progress.
  • Contraindications: For beta blockers: Asthma, depression, Raynaud phenomenon
  • Precautions: Refer to the manufacturer's profile for each drug.
  • Significant possible interactions: Refer to the manufacturer's profile for each drug.
Additional Treatment
General Measures
  • In addition to health supervision visits with primary care physicians, individuals with Marfan syndrome should have regular follow-up with cardiology and ophthalmology.
  • Geneticists generally are involved in making the initial diagnosis.
  • Orthopedic consultation is often helpful.
  • Athletes should have echocardiograms every 6 mos to screen for the presence of aortic root dilatation and worsening valvular insufficiency.
  • Skeletally immature patients should be offered the opportunity to meet with an endocrinologist if they would like to consider hormonal therapy to limit growth.
Additional Therapies
  • Antibiotic prophylaxis for endocarditis prior to medical and dental procedures is no longer uniformly recommended for Marfan patients with mitral valve prolapse.
  • Individuals with significant valvular regurgitation/insufficiency should consult their cardiologists about the necessity of infective endocarditis prophylaxis for their specific conditions.
  • Antibiotic prophylaxis should be given to individuals with a prior history of infective endocarditis or a history of valve replacement or repair of the aorta using graft material.
Surgery/Other Procedures
Cardiac surgery is often required for people with Marfan syndrome who have aortic root diameter >5 cm, rapid rate of aortic root dilatation, or significant aortic valve regurgitation.
Ongoing Care
Follow-Up Recommendations
  • Athletes with Marfan syndrome can participate in low–moderate static/low dynamic sports as long as they do not have moderate or severe mitral regurgitation, have no evidence of aortic root dilatation, and have no family history of aortic dissection or sudden death owing to Marfan syndrome.
  • Individuals with Marfan syndrome should not participate in contact sports or weightlifting.
Patient Monitoring
  • Routine health maintenance visits with a primary care physician.
  • Regular follow-up with cardiology; athletes should have screening echocardiograms every 6 mos.
  • Yearly ophthalmology follow-up owing to high rate of retinal detachment. Patients also have higher rates of myopia and glaucoma.
Diet
No special diet
Patient Education
Information is available from the National Marfan Foundation, 382 Main St., Port Washington, NY 11959; 800–8MARFAN, www.marfan.org.
Prognosis
Life-threatening complications are cardiovascular. With the advancement of techniques to replace the aortic root, individuals with Marfan have a near-normal life span.
Complications
  • Aortic dissection or aortic rupture
  • Aortic valvular insufficiency owing to aortic root dilatation
  • Mitral valve insufficiency, often associated with myxomatous change
  • Bacterial endocarditis
  • Spontaneous pneumothorax
  • Retinal detachment
Pediatric Considerations
Early medical or surgical intervention may reduce the degree of scoliosis.
Pregnancy Considerations
Pregnant women with the Marfan syndrome need to be managed as high-risk patients, preferably with involvement of a cardiologist. The outcome is usually excellent.
Additional Reading
De Paepe A, Devereux RB, Dietz HC, et al. Revised diagnostic criteria for the Marfan syndrome. Am J Med Genet. 1996;62:417–426.
Faivre L, Masurel-Paulet A, Collod-Béroud G, et al. Clinical and molecular study of 320 children with Marfan syndrome and related type I fibrillinopathies in a series of 1009 probands with pathogenic FBN1 mutations. Pediatrics. 2009;123:391–398.
Maron BJ, Chaitman BR, Ackerman MJ, et al. Recommendations for physical activity and recreational sports participation for young patients with genetic cardiovascular diseases. Circulation. 2004;109:2807–2816.
Codes
ICD9
759.82 Marfan syndrome
Clinical Pearls
  • Clinicians should be on the lookout for the musculoskeletal manifestations of Marfan syndrome when performing preparticipation screening.
  • Physicians should carefully evaluate individuals with increased wing span, characteristic facial features, and other stigmata of Marfan syndrome and consider referral to genetics, cardiology, and/or ophthalmology when appropriate.


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