**Core Concept**
Thalidomide is a medication used in the treatment of multiple myeloma, leprosy, and certain types of skin conditions. Its unique mechanism of action involves the inhibition of TNF-alpha production and modulation of the immune system. However, thalidomide is also notorious for its severe teratogenic effects.

**Why the Correct Answer is Right**
Thalidomide's teratogenic effects are primarily due to its ability to induce limb abnormalities in the developing fetus. This is attributed to the drug's mechanism of action, which involves the inhibition of the Sonic hedgehog (Shh) signaling pathway. The Shh pathway plays a crucial role in embryonic development, particularly in the formation of limbs. Thalidomide's inhibition of this pathway disrupts normal limb development, resulting in severe birth defects.

**Why Each Wrong Option is Incorrect**
**Option A:** Thalidomide is not commonly associated with hepatotoxicity. While it can cause some liver enzyme elevations, hepatotoxicity is not a characteristic side effect of the drug.
**Option B:** Thalidomide does not typically cause cardiotoxicity. Its side effect profile is more closely associated with teratogenicity, neuropathy, and thrombocytopenia.
**Option C:** Thalidomide is not typically associated with nephrotoxicity. While it can cause some renal dysfunction in rare cases, nephrotoxicity is not a characteristic side effect of the drug.

**Clinical Pearl / High-Yield Fact**
Thalidomide is a classic example of a drug that was withdrawn from the market due to its severe teratogenic effects. Its history serves as a cautionary tale for the importance of rigorous preclinical testing and postmarketing surveillance.

**Correct Answer:** D.