A nurse is assessing a 25-year-old adult with suspected Marfan syndrome. Which assessment finding would be most characteristic of this genetic connective tissue disorder?

Marfan syndrome is most characteristically identified by a tall, thin body habitus with disproportionately long arms and legs. Other options are not typical for this connective tissue disorder.

Understanding Marfan Syndrome
Marfan syndrome (MFS) is a systemic heritable connective tissue disorder caused by pathogenic variants in the FBN1 gene, which encodes the glycoprotein fibrillin-1 . This genetic defect affects the body's scaffolding, leading to manifestations across multiple body systems, most notably the skeletal, cardiovascular, and ocular systems. Because the clinical presentation can be highly variable and age-dependent, diagnosis relies on a combination of characteristic physical findings and family history, often summarized in the revised Ghent criteria [1,3].

Analysis of Assessment Findings
The most characteristic skeletal finding in an adult with Marfan syndrome is a tall, thin body habitus with disproportionately long arms and legs (dolichostenomelia). This is a direct result of the underlying connective tissue weakness affecting long bone growth and structure. Research in an MFS mouse model confirms that mutations in the Fbn1 gene lead to significant alterations in femoral geometry, including increased bone length, which supports the clinical observation of elongated limbs . When assessing a patient, the nurse would recognize this disproportionate tall stature as a cardinal sign.

The other options represent findings associated with different genetic or developmental disorders, not Marfan syndrome:
- Option 1: Short stature with a webbed neck and low posterior hairline is the classic presentation of Turner syndrome, a chromosomal condition affecting females.
- Option 3: Muscle weakness with delayed motor development is more characteristic of Duchenne muscular dystrophy, a progressive muscle degeneration disorder.
- Option 4: Joint contractures with limited range of motion are not typical of Marfan syndrome. In fact, patients with MFS often present with the opposite finding: joint hypermobility due to ligamentous laxity.

Connecting the Finding to Underlying Pathophysiology and Nursing Assessment
The tall stature and long limbs in MFS are not just an incidental finding; they are a key component of the systemic score used in diagnosis. The nurse's role in assessment is to recognize this pattern and look for associated manifestations. A patient with this body habitus should prompt a focused review of systems. For instance, the nurse should inquire about a history of progressive myopia or other visual changes, as ocular complications like lens subluxation (ectopia lentis) are common and can even be the presenting sign that leads to a diagnosis, as highlighted in case reports [2,3]. Atypical ocular presentations, such as cataracta pulverulenta without classic lens dislocation, have also been documented, emphasizing the need for a thorough assessment even when the most typical findings are absent . Furthermore, the nurse must prioritize a cardiovascular assessment, auscultating for murmurs and palpating for thrills, because the life-threatening complications of MFS stem from aortic root dilation and mitral valve prolapse . The identification of a tall, thin body habitus with long extremities is the critical first step in this cascade of focused assessments, making it the most characteristic finding for this disorder .