Question

Right isomerism is associated with?

• A. Asplenia
• B. Two spleens
• C. One spleen
• D. Polysplenia

Hint:

The spleen is a left-sided organ, so bilateral right-sidedness means it is missing.

Answer 1

The Correct Option is A

Step 1: Isomerism (heterotaxy) describes a situation where paired thoracoabdominal structures lose their normal left-right asymmetry and both sides develop a similar (mirror-image) morphology.
Step 2: In right isomerism, both sides of the body take on right-sided characteristics. This means there are bilateral trilobed (right-type) lungs and bilateral eparterial bronchi.
Step 3: The spleen is normally a left-sided organ. Since both sides become right-sided in right isomerism, the left-sided structure (the spleen) tends to be absent, producing asplenia.
Step 4: Right isomerism is therefore classically called the asplenia syndrome (Ivemark syndrome) and is associated with severe cyanotic congenital heart disease.
Step 5: By contrast, left isomerism gives bilateral left-sided features and is associated with polysplenia (multiple spleens).
Conclusion: Right isomerism corresponds to asplenia (option 1).