What is Marfan syndrome?

Appeared in: UP NHM CHO 7 Sept 2022 (Shift-2)

Explanation

Marfan syndrome is a genetic disorder of the connective tissue.
It is transmitted through an autosomal dominant inheritance pattern, as confirmed by multiple clinical genetics resources.
This means only one copy of the mutated FBN1 gene, inherited from one parent, is sufficient to cause the disorder.
The condition affects both males and females equally and can be passed on by an affected parent to 50% of their offspring, on average.

Option A: This is incorrect. Sex-linked recessive disorders are caused by mutations on the X chromosome and predominantly affect males. Marfan syndrome affects males and females equally.
Option B: This is incorrect. While sex-linked dominant disorders can affect both sexes, they are caused by mutations on the X chromosome. Marfan syndrome is caused by a mutation on an autosome (chromosome 15).
Option C: This is incorrect. Autosomal recessive conditions require two copies of the mutated gene (one from each parent) for the disease to manifest. Marfan syndrome only requires one copy.

Clinical Relevance

Nursing practice connection: Knowing Genetic inheritance pattern of Marfan syndrome helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses play a key role in monitoring patients with Marfan syndrome for life-threatening cardiovascular complications, such as aortic aneurysm, dissection, and mitral valve prolapse, through regular vital sign checks and assessment for chest pain or shortness of breath.
Patient education is a critical nursing function, focusing on activity restrictions (e.g., avoiding contact sports), the importance of consistent follow-up with echocardiograms, and recognizing symptoms that require immediate medical attention.
Nurses should facilitate referrals for genetic counseling for patients and their families to help them understand the 50% risk of transmission to each child and make informed decisions about family planning.

How to Approach the Question

This is a factual recall question that tests your knowledge of a specific genetic disorder.
First, identify the core subject of the question, which is 'Marfan syndrome'.
Next, access your knowledge base about this condition. The most fundamental characteristic to recall is its mode of genetic transmission.
Systematically evaluate each option, which presents a different pattern of inheritance (sex-linked vs. autosomal, recessive vs. dominant).
Compare the known inheritance pattern of Marfan syndrome with the options provided.
Select the option that correctly identifies Marfan syndrome as an 'Autosomal dominant condition'.

Concept Tested & Keywords

QuCcs2pGbBXegXQDQMG6Tl

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 155-157

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 2173-2175

Practise the full UP NHM CHO 7 Sept 2022 (Shift-2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.