Type II complement component 8 deficiency(C8D2)

MedGen UID:: 462430
•Concept ID:: C3151080
•: Disease or Syndrome

Synonyms:	C8 beta deficiency; C8 deficiency type II; C8B DEFICIENCY; COMPLEMENT C8 DEFICIENCY, TYPE II; Complement component 8 deficiency type 2; COMPLEMENT COMPONENT 8B DEFICIENCY; Human complement C8-beta deficiency

Gene (location): Gene(s) directly associated with this condition or phenotype.	C8B (1p32.2)

Monarch Initiative:	MONDO:0013421
OMIM®:	613789

Definition

Patients with deficiency of C8 suffer from recurrent neisserial infections, predominantly with meningococcus infection of rare serotypes. Most such patients are discovered among those having their first episode of meningitis at ages older than 10 years (Ross and Densen, 1984). Two types of inherited C8 deficiency have been reported in humans: type I (613790), in which only C8 alpha (C8A, 120950) and C8 gamma (C8G; 120930) are deficient, and type II, in which only C8 beta is deficient (Marcus et al., 1982; Tedesco et al., 1983). The 2 types are clinically indistinguishable (Ross and Densen, 1984). [from OMIM]

Additional description

From MedlinePlus Genetics
Complement component 8 deficiency is a disorder that causes the immune system to malfunction, resulting in a form of immunodeficiency. Immunodeficiencies are conditions in which the immune system is not able to protect the body effectively from foreign invaders such as bacteria. People with complement component 8 deficiency have a significantly increased risk of recurrent bacterial infections, particularly by a bacterium called Neisseria meningitidis. Infection by this bacterium causes inflammation of the membranes surrounding the brain and spinal cord (meningitis). Although meningitis can be life-threatening, individuals with complement component 8 deficiency are less likely to die from the infection than people in the general population who contract it.

The severity of complement component 8 deficiency varies widely. While some people with this condition experience one or more infections, others do not have any health problems related to the disorder.

There are two types of complement component 8 deficiency, types I and II, classified by their genetic cause. The two types have the same signs and symptoms. https://medlineplus.gov/genetics/condition/complement-component-8-deficiency