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Complement Component Deficiencies

What are complement component deficiencies? 

Complement component deficiencies are a group of conditions in which affected individuals have a deficiency of one of the serum proteins of the complement system. These proteins play an important role in defending the body from infections, along with mediating the prevention and pathogenesis of immune complex diseases. 

The most common form is complement component 2 deficiency.

What are the symptoms of complement component deficiencies?

Symptoms depend on which specific protein is lacking within the complement system. Some forms present as susceptibility to bacterial infections, such as meningococcal disease, while others are characterized by autoimmune disorders such as systemic lupus erythematosus (SLE) and hereditary angioedema (HAE). 

What causes complement component deficiencies?

The genes that code for the production of the proteins in the complement system are mutated in individuals with these conditions, most of which are found on chromosome 19. 

How are complement component deficiencies diagnosed?

Doctors should suspect a complement component deficiency if a patient presents with recurrent infections, autoimmune disease, and episodes of angioedema that do not go away with histamines or epinephrine. A doctor will ask about medical and family history, and then utilize several screening tests to diagnose this condition.

What are the treatments for complement component deficiencies?

There is no cure for complement component deficiencies, and treatment is aimed at the specific presentation of each affected individual. This may mean treating infections as they appear or addressing any autoimmune issues and conditions. 

Where can I find out more about complement component deficiencies?

Complement Component Deficiencies Articles