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Behçet's disease associated with complement component 9 (C9) deficiency

T Horiuchi1, H Tsukamoto, T Sawabe

  • 1Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences , 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 , Japan.

Modern Rheumatology
|January 4, 2014
PubMed

Insights

This study investigates Behçet's disease and complement component 9 (C9) deficiency. Findings suggest C9 is not essential in Behçet's disease pathogenesis, despite its role in disease activity.

Area of Science:

  • Immunology
  • Genetics
  • Rheumatology

Background:

  • Behçet's disease is a multisystem inflammatory disorder of unknown cause.
  • Elevated plasma complement component 9 (C9) levels correlate with Behçet's disease activity.
  • This correlation suggests a potential role for C9 in Behçet's disease pathogenesis.

Purpose of the Study:

  • To investigate the role of complement component 9 (C9) in Behçet's disease pathogenesis.
  • To report a case of Behçet's disease with complete C9 deficiency (C9D).

Main Methods:

  • Case report of a Behçet's disease patient with C9 deficiency.
  • Genetic analysis to identify the mutation causing C9 deficiency (homozygous nonsense mutation at Arg-95 of C9, R95X).
  • Clinical evaluation of Behçet's disease symptoms.

Main Results:

  • The patient presented with classic Behçet's disease symptoms: uveitis, oral aphthae, genital ulcers, and arthritis.
  • The patient was diagnosed with complete C9 deficiency (C9D) due to a homozygous nonsense mutation (R95X).

Conclusions:

  • Complement component 9 (C9) deficiency does not preclude the development of Behçet's disease.
  • C9 does not appear to play an essential role in the pathogenesis of Behçet's disease.
  • Further research is needed to elucidate the exact role of C9 in Behçet's disease activity.

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