Mutation in protein associated with restrictive cardiomyopathy?
**Core Concept**
Restrictive cardiomyopathy (RCM) is a condition characterized by the stiffening of the heart muscle, leading to impaired diastolic relaxation and filling of the heart chambers. This condition can be caused by various factors, including genetic mutations affecting cardiac proteins.
**Why the Correct Answer is Right**
The correct answer is associated with a mutation in the cardiac troponin T (cTnT) gene, which codes for the troponin T protein. This protein plays a crucial role in regulating muscle contraction in cardiac myocytes. Mutations in the cTnT gene have been identified as a common cause of familial restrictive cardiomyopathy. These mutations lead to abnormal interactions between the troponin T and tropomyosin proteins, resulting in impaired muscle relaxation and contraction.
**Why Each Wrong Option is Incorrect**
* **Option A:** Mutations in the cardiac troponin I (cTnI) gene are associated with dilated cardiomyopathy, not restrictive cardiomyopathy.
* **Option B:** Mutations in the lamin A/C gene are associated with dilated cardiomyopathy, conduction system disease, and other conditions, but not primarily restrictive cardiomyopathy.
* **Option D:** Mutations in the desmin gene are associated with arrhythmogenic right ventricular cardiomyopathy (ARVC) and myofibrillar myopathy, but not restrictive cardiomyopathy.
**Clinical Pearl / High-Yield Fact**
Familial restrictive cardiomyopathy is a rare but important cause of heart failure, often presenting with symptoms of diastolic dysfunction and preserved ejection fraction.
**Correct Answer:** C.