**Core Concept:** Purpura Fulminans is a rare, life-threatening disorder characterized by extensive hemorrhagic necrosis of the skin and subcutaneous tissues, caused by disseminated intravascular coagulation (DIC). It can be associated with underlying infections, autoimmune diseases, or certain medications. In this case, the history of a male sibling dying from the same condition and normal siblings indicate a genetic cause.

**Why the Correct Answer is Right:** The correct answer is **D. Inherited Factor V Leiden Mutation** because Factor V Leiden is a genetic mutation that predisposes individuals to develop DIC, including Purpura Fulminans. Factor V Leiden is a point mutation in the Factor V gene, which results in an abnormally active clotting factor. In this case, the sibling who died and the affected newborn girl both have the genetic predisposition, leading to DIC and Purpura Fulminans.

**Why Each Wrong Option is Incorrect:**

**A. Factor V Leiden Mutation:** This option is incorrect because the siblings without the condition are normal, suggesting that Factor V Leiden mutation alone is not sufficient to cause Purpura Fulminans.

**B. Infections:** While infections can cause DIC and Purpura Fulminans, the presence of Factor V Leiden mutation in the affected siblings makes infections less likely as the sole cause.

**C. Autoimmune Disease:** While autoimmune diseases can lead to DIC, the fact that only one sibling has this condition and the genetic predisposition in the affected siblings makes autoimmune diseases less likely as the sole cause.

**D. Medications:** Some medications can cause DIC, but the family history suggests that the genetic predisposition is the primary cause, making medications less likely as the sole cause.

**Clinical Pearl:** This case highlights the importance of considering genetic factors in diagnosing and treating patients with Purpura Fulminans. Inherited Factor V Leiden mutation should be investigated in patients with DIC and Purpura Fulminans, even in the absence of infections or other obvious causes. Early identification and management of this genetic predisposition can prevent severe complications and improve outcomes in affected individuals.