Complement deficiency

Complement deficiency
Classification and external resources
ICD-10	D 84.1
ICD-9	279.8
OMIM	217000 120820, 120900, 610102
DiseasesDB	1847 1869, 1873, 7384, 34381
eMedicine	med/419 ped/447

Complement deficiency is an immunodeficiency of absent or suboptimal functioning of one of the complement system proteins.^[1]

The disorders can be divided into two categories:

Disorders of the proteins that act to inhibit the complement system (such as C1-inhibitor) can lead to an overactive response, causing conditions such as hereditary angioedema and hemolytic-uremic syndrome.

Disorders of the proteins that act to activate the complement system (such as C3) can lead to an underactive response, causing greater susceptibility to infections.

Because there are redundancies in the immune system, many complement disorders are never diagnosed. A recent study estimated that less than 10% are identified.^[2]

Hypocomplementemia

The term "hypocomplementemia" is a more general term used to describe decreased complement levels.^[3] The term "secondary complement disorder" is sometimes used to refer to low complement levels that are not directly due to a genetic cause but secondary to another medical condition.^[4]

These levels can be used to distinguish conditions:

Systemic lupus erythematosus causes low C3 and C4
Membranoproliferative glomerulonephritis causes low C3, but normal C4

References

^ Sherwood L. Gorbach; John G. Bartlett; Neil R. Blacklow (2004). Infectious diseases. Lippincott Williams & Wilkins. pp. 11–. ISBN 9780781733717. http://books.google.com/?id=91altE1evAsC&pg=PA11. Retrieved 30 May 2010.
^ Sjöholm AG, Jönsson G, Braconier JH, Sturfelt G, Truedsson L (2006). "Complement deficiency and disease: an update". Mol. Immunol. 43 (1–2): 78–85. doi:10.1016/j.molimm.2005.06.025. PMID 16026838.
^ "hypocomplementemia" at Dorland's Medical Dictionary
^ http://emedicine.medscape.com/article/136368-overview

Immune disorders: Lymphoid and complement immunodeficiency (D80–D85, 279.0–4)

Primary

Antibody/humoral (B)

Hypogammaglobulinemia	X-linked agammaglobulinemia · Transient hypogammaglobulinemia of infancy

Dysgammaglobulinemia	IgA deficiency · IgG deficiency · IgM deficiency · Hyper IgM syndrome (2, 3, 4, 5) · Wiskott-Aldrich syndrome · Hyper-IgE syndrome

Other	Common variable immunodeficiency · ICF syndrome

T cell deficiency (T)

thymic hypoplasia: hypoparathyroid (Di George's syndrome) · euparathyroid (Nezelof syndrome, Ataxia telangiectasia)

peripheral: Purine nucleoside phosphorylase deficiency · Hyper IgM syndrome (1)

Severe combined (B+T)

x-linked: X-SCID
autosomal: Adenosine deaminase deficiency · Omenn syndrome · ZAP70 deficiency · Bare lymphocyte syndrome

Acquired

AIDS

Leukopenia:
Lymphocytopenia

Idiopathic CD4+ lymphocytopenia

Complement deficiency

C1-inhibitor (Angioedema/Hereditary angioedema) · Complement 2 deficiency/Complement 4 deficiency · MBL deficiency · Properdin deficiency · Complement 3 deficiency · Terminal complement pathway deficiency · Paroxysmal nocturnal hemoglobinuria · Complement receptor deficiency

M: LMC

cell/phys/auag/auab/comp, igrc

imdf/ipig/hyps/tumr

proc, drug(L3/4)

Complement deficiency

Hypocomplementemia

See also

References