What is the appropriate workup for a teenager with a marfanoid (marfan-like) habitus?

Diagnostic Workup for a Teenager with Marfanoid Habitus

The appropriate workup for a teenager with marfanoid habitus should include a comprehensive cardiovascular evaluation with echocardiography, ophthalmologic examination with slit-lamp evaluation, skeletal assessment using the Beighton scale, and genetic testing for FBN1 mutations. 1

Initial Evaluation

Physical Examination

• Detailed assessment of:
  • Height, arm span, and upper/lower segment ratio
  • Skeletal features: pectus deformities, scoliosis, joint hypermobility
  • Facial features: dolichocephaly, enophthalmos, downslanting palpebral fissures
  • Skin for striae
  • Joint hypermobility using the Beighton scale 1

Scoring System for Systemic Features

• Wrist AND thumb sign = 3 points (wrist OR thumb sign = 1 point)
• Pectus carinatum = 2 points (pectus excavatum or chest asymmetry = 1 point)
• Hindfoot deformity = 2 points (pes planus = 1 point)
• Pneumothorax = 2 points
• Dural ectasia = 2 points
• Protrusio acetabuli = 2 points 2

Cardiovascular Evaluation

• Echocardiogram to assess aortic root dimensions and valve function
  • Z-score calculation based on age, sex, and body surface area
  • Aortic root dilation defined as Z-score ≥2 in adults, ≥3 in children 1
• If aortic root is normal: repeat echocardiogram every 2-3 years until adult height is reached
• If aortic root is dilated: more frequent monitoring (every 6-12 months) 2

Ophthalmologic Evaluation

• Complete dilated eye examination with slit-lamp evaluation to detect:
  • Ectopia lentis (lens dislocation)
  • Myopia
  • Other ocular manifestations 1

Imaging Studies

• MRI or CT angiography of the entire aorta, particularly in young adults
• MRI for assessment of dural ectasia
• X-rays for evaluation of protrusio acetabuli and scoliosis when clinically indicated 1

Genetic Testing

• FBN1 gene sequencing for Marfan syndrome
• Consider testing for related disorders:
  • TGFBR1, TGFBR2 gene sequencing for Loeys-Dietz syndrome
  • SMAD3, TGFB2, TGFB3 gene sequencing if Loeys-Dietz syndrome is suspected
  • TNXB gene analysis if Ehlers-Danlos syndrome (hypermobile type) is suspected 2, 1

Differential Diagnosis Considerations

Loeys-Dietz Syndrome

• Features include characteristic facial features, bifid uvula/cleft palate, arterial tortuosity
• Requires CT or MRI angiography of thorax, abdomen, and pelvis
• TGFBR1 and TGFBR2 gene sequencing 2

Congenital Contractural Arachnodactyly (Beals Syndrome)

• Features include contractures of digits, elbows, knees; "crumpled" ear helices
• Echocardiography recommended as MVP and aortic dilation have been reported 2

Ehlers-Danlos Syndrome (Hypermobile Type)

• Joint hypermobility (Beighton score ≥5)
• Soft, velvety skin with normal or slightly increased extensibility
• Absence of skin fragility
• Aortic root dilation occurs in 25-33% of cases 2

Diagnostic Criteria for Marfan Syndrome (Revised Ghent Nosology)

Diagnosis can be established with any of the following combinations:

1. Aortic root dilation (Z-score ≥2) AND ectopia lentis
2. Aortic root dilation (Z-score ≥2) AND pathogenic FBN1 mutation
3. Aortic root dilation (Z-score ≥2) AND systemic score ≥7 points
4. Ectopia lentis AND FBN1 mutation associated with aortic disease 1

Management Considerations

Cardiovascular Management

• Beta-blocker therapy for aortic root dilation
• Consider surgical repair if:
  • Aortic diameter >4.5 cm
  • Rate of dilation approaches 1 cm/year
  • Progressive aortic regurgitation develops 2, 1

Follow-up Recommendations

• For normal aortic root: echocardiogram every 2-3 years until adult height is reached
• For dilated aortic root:
  • Annual echocardiogram if diameter <4.5 cm and growth rate <0.5 cm/year
  • Echocardiogram every 6 months if diameter >4.5 cm or growth rate >0.5 cm/year
  • Imaging of the entire aorta every 2-3 years 2, 1

Common Pitfalls to Avoid

• Failing to perform complete cardiovascular imaging beyond echocardiography
• Overlooking ophthalmologic examination, which can provide crucial diagnostic information
• Not considering related disorders like Loeys-Dietz syndrome, which may require different management approaches
• Using adult diagnostic criteria for children, as some features are age-dependent
• Inadequate follow-up of patients with normal initial evaluations, as manifestations may develop over time

Early identification and appropriate management are critical for patients with marfanoid features to prevent life-threatening complications such as aortic dissection and to improve their quality of life and life expectancy.