Which of the following autosomal dominant disorder is characterized by formation of multiple gastrointestinal polyps along with pigmented lesions around the oral cavity

Okay, let's tackle this question. The user is asking about an autosomal dominant disorder with multiple gastrointestinal polyps and pigmented lesions around the oral cavity. The options aren't provided, but I need to figure out the correct answer based on the description.

First, I remember that there are several syndromes involving GI polyps. The most common ones are Peutz-Jeghers syndrome (PJS), Familial Adenomatous Polyposis (FAP), and Juvenile Polyposis. The key here is the pigmented lesions around the mouth.

Peutz-Jeghers is known for hamartomatous polyps in the GI tract, especially the small intestine, and mucocutaneous pigmentation. The pigmentation usually appears as brown or black spots on the lips, oral mucosa, and sometimes the hands and feet. It's an autosomal dominant condition caused by mutations in the STK11 gene.

FAP, on the other hand, is associated with adenomatous polyps in the colon and rectum, and it's linked to the APC gene. But FAP doesn't have the pigmented lesions. Juvenile Polyposis involves juvenile polyps, often in the colon, and may have some skin findings, but not the oral pigmentation described here.

So, the correct answer must be Peutz-Jeghers syndrome. The other options don't fit the pigmentation feature. The user's question mentions "pigmented lesions around the oral cavity," which is a hallmark of PJS. Let me check if there's another syndrome with similar features. Maybe something else? No, I think PJS is the right one here.

Now, I need to structure the explanation as per the user's instructions. Core concept is the autosomal dominant disorder with GI polyps and oral pigmentation. Correct answer is PJS. Then explain why the others are wrong: FAP has colon polyps but no pigmentation, Juvenile Polyposis doesn't have the pigmented lesions. Clinical pearl would be to remember the STK11 gene and the specific features. Make sure the answer is concise and fits the character limit.

**Core Concept**
This question tests knowledge of autosomal dominant polyposis syndromes. Peutz-Jeghers syndrome (PJS) is distinguished by hamartomatous gastrointestinal polyps and mucocutaneous pigmentation, while Familial Adenomatous Polyposis (FAP) involves adenomatous colon polyps without pigmentation.

**Why the Correct Answer is Right**
Peutz-Jeghers syndrome is caused by mutations in the **STK11/LKB1** tumor suppressor gene. It presents with **hamartomatous polyps in the small intestine** (especially jejunum) and **mucocutaneous melanin pigmentation** (dark spots on lips, oral mucosa, and perioral skin). These pigmented lesions are benign but pathognomonic for PJS.

**Why Each Wrong Option is Incorrect**
**Option A:** Familial Adenomatous Polyposis (FAP) causes **adenomatous polyps in the colon** (not oral pigmentation) and is linked to the **APC gene**.
**Option B:** Juvenile Polyposis syndrome features **juvenile polyps in the stomach and colon

✓ Correct Answer: A. Peutz-Jeghers syndrome