From the Guidelines
To examine for Marfanoid habitus, begin with a systematic assessment of the patient's physical characteristics, including measuring height and arm span, calculating the upper-to-lower body segment ratio, and examining for arachnodactyly, high-arched palate, pectus excavatum or carinatum, scoliosis, joint hypermobility, pes planus, and dolichostenomelia, as these features are indicative of abnormal connective tissue development, often due to mutations in fibrillin-1 or related genes, as noted in studies such as 1 and 1.
Key Features to Examine
- Measure the patient's height and arm span; Marfanoid habitus typically presents with an arm span that exceeds height by at least 5 cm.
- Calculate the upper-to-lower body segment ratio by measuring the distance from the top of the pubic symphysis to the floor and subtracting this from total height; a ratio less than 0.85 suggests Marfanoid features.
- Examine the hands for arachnodactyly (long, slender fingers) using the Steinberg thumb sign (thumb extends beyond the ulnar border when folded in a closed fist) and the Walker-Murdoch wrist sign (thumb and fifth finger overlap when encircling the opposite wrist).
- Look for a high-arched palate, pectus excavatum (sunken chest) or pectus carinatum (protruding chest), scoliosis, and joint hypermobility.
- Also assess for pes planus (flat feet) and dolichostenomelia (long, thin limbs).
Comprehensive Evaluation
A comprehensive examination should also include:
- Ophthalmologic assessment for lens dislocation, as noted in 1.
- Cardiovascular evaluation for aortic root dilation, which requires specialized equipment, as discussed in 1 and 1.
- Consideration of genetic testing, such as TGFBR1 and TGFBR2 gene sequencing, for patients with suspected Marfan syndrome or related disorders, as mentioned in 1 and 1.
Importance of Early Detection
Early detection of Marfanoid habitus and related connective tissue disorders is crucial for preventing complications, such as aortic dissection and cardiac valve problems, as emphasized in 1 and 1. Regular follow-up imaging and monitoring are essential for patients with confirmed Marfan syndrome or those at risk, as recommended in 1.
From the Research
Examining for Marfanoid Habitus
To examine for marfanoid habitus, several key features should be assessed, including:
- Tall stature and long, narrow limbs 2, 3
- Long and narrow head shape 2
- Skeletal abnormalities such as scoliosis, pectus excavatum, or protrusio acetabuli 2, 4, 3
- Musculoskeletal manifestations like ligamentous laxity, dural ectasia, or leg length inequality 4, 3
- Ocular features like lens subluxation, retinal detachment, or myopia 2, 4, 5
Key Features for Differentiation
When differentiating between marfanoid habitus and Marfan syndrome, the following features can serve as "red flags" 5:
- Pectus carinatum
- Reduced elbow extension
- Hindfoot deformity
- Gothic palate
- Downslanting palpebral fissures
- Lens subluxation
- Myopia ≥ 3 dioptres
- Remarkably high stature
Diagnostic Approach
The diagnosis of Marfan syndrome is guided by the Ghent nosology 4, 6, 5, which considers a combination of systemic, skeletal, and ocular features. A comprehensive clinical evaluation, including a physical examination and assessment of family history, is essential for accurate diagnosis 5.