Question
A 32-year-old woman reports repeated painful mouth sores. On further questioning, she also describes recurrent genital sores and episodes of eye redness with discomfort.
Which HLA subtype is most strongly linked to this condition?
a. HLA-B27
b. HLA-B52
c. HLA-B51
d. HLA-DR4
e. HLA-DR2
Answer
HLA-B51
Explanation
This clinical picture is classic for Behçet’s syndrome, which is characterized by the triad of:
- Recurrent oral ulcers
- Recurrent genital ulcers
- Uveitis (painful red eye)
The strongest HLA association is HLA-B51, particularly seen in populations along the ancient Silk Road (e.g., Turkey, Middle East, East Asia).
Behçet’s is a multisystem vasculitis affecting both arteries and veins. Other features include thrombosis, skin lesions (erythema nodosum), arthritis, and neurological involvement.
Diagnosis is clinical (no definitive test). A pathergy test (skin hyperreactivity after needle prick) may support diagnosis.
Cheat Sheet for Exam
Behçet’s syndrome
- Type: Multisystem vasculitis
- Key triad:
- Oral ulcers
- Genital ulcers
- Uveitis
- HLA association: HLA-B51
- Other features:
- DVT / thrombophlebitis
- Arthritis
- CNS involvement
- Erythema nodosum
- Diagnosis: Clinical
- Special test: Pathergy test (+)
Flash Cards
Flashcard 1
Q: What is the classic triad of Behçet’s syndrome?
A: Oral ulcers, genital ulcers, uveitis
Explanation: These three features define the disease clinically.
Flashcard 2
Q: Which HLA type is strongly associated with Behçet’s syndrome?
A: HLA-B51
Explanation: Most characteristic genetic association.
Flashcard 3
Q: What type of pathology is Behçet’s syndrome?
A: Multisystem vasculitis
Explanation: Affects both arteries and veins.
Flashcard 4
Q: What is a pathergy test?
A: Skin hyperreactivity after needle prick
Explanation: Formation of pustule at puncture site suggests Behçet’s.
MCQs
MCQ 1
A 29-year-old man has oral ulcers, genital ulcers, and blurred vision. Which HLA is most likely associated?
a. HLA-B27
b. HLA-DR3
c. HLA-B51
d. HLA-DR2
Answer: c
Explanation: Classic Behçet’s → HLA-B51.
MCQ 2 (False type)
Which of the following statements about Behçet’s syndrome is false?
a. It is a vasculitis
b. It commonly presents with oral ulcers
c. It has a definitive diagnostic blood test
d. It may cause uveitis
Answer: c
Explanation: There is NO definitive test; diagnosis is clinical.
MCQ 3
Which condition is most strongly associated with HLA-B27?
a. Behçet’s syndrome
b. Ankylosing spondylitis
c. Rheumatoid arthritis
d. SLE
Answer: b
Explanation: HLA-B27 → seronegative spondyloarthropathies.
MCQ 4
A patient develops pustules at the site of a needle prick. This is known as:
a. Koebner phenomenon
b. Nikolsky sign
c. Pathergy reaction
d. Auspitz sign
Answer: c
Explanation: Pathergy is characteristic of Behçet’s.
MCQ 5
Which of the following is NOT a common feature of Behçet’s syndrome?
a. Oral ulcers
b. Genital ulcers
c. Uveitis
d. Anti-dsDNA antibodies
Answer: d
Explanation: Anti-dsDNA is seen in SLE, not Behçet’s.
Summary for Quick Exam Revision
Behçet’s syndrome is a multisystem vasculitis characterized by the classic triad of recurrent oral ulcers, genital ulcers, and uveitis. It commonly affects young adults and is more prevalent in regions along the Silk Road. The strongest genetic association is HLA-B51, although it is not used diagnostically. The disease can involve multiple systems, including vascular (thrombosis), dermatological (erythema nodosum), musculoskeletal (arthritis), and neurological systems. Diagnosis is clinical, supported by features such as a positive pathergy test. There is no single definitive investigation. Differentiation from other autoimmune diseases is essential, especially SLE and seronegative spondyloarthropathies. Early recognition is important due to potential complications like vision loss and vascular events.