Question

Which of the following diseases is associated with the HLA B 27 subtype?

• A. Addison's disease
• B. Myasthenia gravis
• C. Reiter's syndrome
• D. Psoriasis

Hint:

Think of the seronegative spondyloarthropathy with a triad of arthritis, conjunctivitis and urethritis.

Answer 1

The Correct Option is C

Step 1: Recall what HLA B27 flags.
HLA B27 is a tissue marker best known for its link to a family of joint diseases called seronegative spondyloarthropathies, meaning arthritis without rheumatoid factor in the blood.

Step 2: List the diseases in that family.
This family covers ankylosing spondylitis, reactive arthritis, arthritis linked to inflammatory bowel disease, and the joint form of psoriasis. Reactive arthritis was formerly called Reiter's syndrome, and shows one of the tightest HLA B27 links of all diseases.

Step 3: Confirm the classic triad.
Reiter's syndrome classically presents with joint inflammation, eye inflammation, and inflammation of the urethra, usually following a bowel or genital infection. This triad, together with a strong HLA B27 link, makes it the clear answer among the choices given.

Step 4: Check why the rest do not fit.
Addison's disease is an adrenal gland disorder with no HLA B27 tie. Myasthenia gravis involves antibodies against the neuromuscular junction and is tied more to HLA DR3, not B27. Plain psoriasis of the skin has its own separate HLA links, and only its arthritis form has a partial, weaker HLA B27 connection compared with Reiter's syndrome.

Step 5: Answer.
$\text{Reiter's syndrome}$ carries the strongest HLA B27 association among the choices.
\[ \boxed{\text{Reiter's syndrome}} \]