What is Marfan syndrome?

NORCERT 8 Mains-2025

Pathology & Genetics

Easy

Appeared in: NORCERT 8 Mains-2025

Explanation

Marfan syndrome is an autosomal dominant condition, meaning only one copy of the mutated gene from a parent is sufficient to cause the disorder.
It is caused by mutations in the FBN1 gene on chromosome 15, which is responsible for producing fibrillin-1, a key protein in connective tissue.
This inheritance pattern results in a 50% chance of an affected person passing the condition to each of their children, affecting males and females equally.
The disorder is characterized by a triad of symptoms affecting the skeletal, ocular, and cardiovascular systems due to weakened connective tissue.

Option A: X-linked recessive disorders are caused by mutations on the X chromosome and primarily affect males. Marfan syndrome affects males and females equally because the responsible gene is on an autosome (non-sex chromosome).
Option B: X-linked dominant disorders are also caused by mutations on the X chromosome. This is not the inheritance pattern for Marfan syndrome.
Option C: Autosomal recessive conditions require two copies of the mutated gene (one from each parent) for the disease to appear. Marfan syndrome only requires one mutated gene copy.

Visual 1: Diagram: An inheritance chart illustrating the 50% probability of transmission in autosomal dominant conditions.
Visual 2: Illustration: A figure showing the classic physical features of Marfan syndrome, such as tall stature, arachnodactyly (long fingers), and pectus excavatum.
Visual 3: Infographic: A summary of the major systems affected by Marfan syndrome (skeletal, ocular, cardiovascular) with key signs for each.

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 vital role in patient education, especially regarding genetic counseling. For Marfan syndrome, this includes explaining the 50% inheritance risk to affected individuals and their families.
Cardiovascular monitoring is a critical nursing responsibility. Regular echocardiograms are essential to track aortic root dilation, and nurses must educate patients on the importance of adherence to prevent aortic dissection.
Patients with Marfan syndrome are often advised to avoid contact sports and heavy isometric exercise to reduce stress on the aorta. Nurses help reinforce these activity restrictions.

How to Approach the Question

First, identify the core subject of the question, which is 'Marfan syndrome'.
Recognize that the options are all different types of genetic inheritance patterns.
The question is asking you to recall the specific inheritance pattern associated with Marfan syndrome.
Access your knowledge of common genetic disorders. Recall that Marfan syndrome is a well-known example of a connective tissue disorder.
Systematically evaluate the options. Eliminate patterns that don't fit. For example, X-linked patterns are tied to sex chromosomes and often affect one gender more than the other, which is not the primary characteristic of Marfan's.
Differentiate between autosomal dominant (one gene copy needed) and autosomal recessive (two copies needed). Recall that Marfan syndrome is dominant, and select the corresponding option.

Concept Tested & Keywords

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