Senile cardiac amyloidosis is due to deposition of amyloid which is similar to
**Core Concept**
Senile cardiac amyloidosis is a condition characterized by the deposition of amyloid fibrils in the heart, leading to restrictive cardiomyopathy. The amyloid protein involved is a variant of transthyretin (TTR), a transport protein normally produced in the liver.
**Why the Correct Answer is Right**
The amyloid deposits in senile cardiac amyloidosis are composed of wild-type transthyretin (TTR), which accumulates in the heart due to a senile systemic amyloidosis. This leads to the disruption of cardiac structure and function, resulting in symptoms such as heart failure and arrhythmias. The deposition of amyloid fibrils in the heart is a hallmark of this condition.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the amyloid protein in senile cardiac amyloidosis is not associated with plasma cell dyscrasias or multiple myeloma, which typically involve the deposition of lambda or kappa light chain amyloid.
**Option B:** This option is incorrect because the amyloid protein in senile cardiac amyloidosis is not related to hereditary amyloidosis, which involves mutations in the TTR gene leading to the production of abnormal TTR variants.
**Option C:** This option is incorrect because the amyloid protein in senile cardiac amyloidosis is not associated with amyloidosis due to chronic inflammation, such as in rheumatoid arthritis or tuberculosis.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that senile cardiac amyloidosis can mimic other conditions such as hypertrophic cardiomyopathy or restrictive cardiomyopathy, making it crucial to consider this diagnosis in patients with unexplained heart failure or arrhythmias.
**Correct Answer:** A. Wild-type transthyretin (TTR).