**Question:** All the following diseases are associated with HLA-B27 & Uveitis, except:

A. Ankylosing Spondylitis
B. Reiter's Syndrome
C. Bechet's Disease
D. Sjögren's Syndrome

**Core Concept:**

HLA-B27 is a major histocompatibility complex (MHC) class I antigen present in the majority of individuals with ankylosing spondylitis (AS), Reiter's syndrome (RS), and other spondyloarthropathies. Uveitis is an inflammation of the uveal tissue in the eye, often associated with these conditions.

**Why the Correct Answer is Right:**

Uveitis is a common feature in several inflammatory disorders, including those related to HLA-B27:

1. Ankylosing Spondylitis (AS): A chronic inflammatory disorder affecting the spine, sacroiliac joints, and other joints. It is characterized by asymmetrical, migratory, and asymmetrical sacroiliitis, as well as peripheral arthritis.

2. Reiter's Syndrome (RS): A triad of symptoms comprising urethritis, conjunctivitis, and arthritis. HLA-B27 is a significant marker for this disease.

3. Bechet's Disease: An inflammatory disorder affecting blood vessels, bones, joints, and the central nervous system. It is not strictly associated with HLA-B27.

4. Sjögren's Syndrome: A systemic autoimmune disorder affecting the exocrine glands, particularly the salivary and lacrimal glands, leading to dry eyes and mouth. It is not associated with HLA-B27.

**Why Each Wrong Option is Incorrect:**

Option A (Bechet's Disease) and Option D (Sjögren's Syndrome) are not strictly associated with HLA-B27 and are not primarily involved in uveitis.

Option B (Reiter's Syndrome) is associated with HLA-B27 and presents with uveitis, along with urethritis and conjunctivitis.

Option C (Ankylosing Spondylitis) is also associated with HLA-B27 and involves uveitis in some cases. However, it primarily affects the spine and sacroiliac joints, with no specific ocular involvement.

**Clinical Pearl:**

The association between HLA-B27 and uveitis is a clinical clue to consider these conditions in patients presenting with uveitis. A thorough clinical examination of the affected patient is crucial to differentiate between these entities and rule out other causes of uveitis.

**Why the Correct Answer is Right:**

The correct answer, Bechet's Disease, is not associated with HLA-B27 and does not commonly cause uveitis. Reiter's Syndrome is a peculiar disease entity that involves uveitis along with urethritis and conjunctivitis, making it the correct answer.

**Why Each Wrong Option