Complement component C1r/C1s deficiency is a disorder in which the body lacks the necessary amounts of the proteins C1r and C1s, which are involved in the complement system. The complement system is related to the body’s immune system, and it helps with clearing infections, removing dying cells, and helping with immune responses.
Patients with C1r/C1s deficiency may be prone to other diseases such as systemic lupus erythematosus (SLE), an autoimmune disease in which the immune system mistakenly attacks healthy tissue of the skin, joints, kidneys, brain, and other organs. Rheumatoid arthritis (RA) may also occur, another autoimmune disorder in which the immune system attacks joint tissue, causing swollen, tender, and/or stiff joints. Other symptoms include recurring infection and angioedema (swelling beneath the skin). Symptoms typically present before age 10.
C1r and C1s deficiencies are caused by various mutations in genes which are inherited in an autosomal recessive pattern. “Autosomal recessive” means that someone must have two copies of the mutant gene to have the condition.
A family history of recurrent autoimmune disease, infection, and/or chronic angioedema may be the first clue in diagnosing complement component C1r/C1s deficiency. Additional blood tests may be done to determine if the type of complement deficiency present is one involving C1r/C1s.
There is no treatment or cure for C1r/C1s deficiency, but it’s symptoms can be managed individually. Infections in C1r/C1s deficient individuals are more common and often need treatment by medical professionals. In addition, it is important to discuss treatment plans for autoimmune diseases such as SLE and RA if those occur.
If you or a family member has been diagnosed with complement component C1r/C1s deficiency, speak with your doctor to learn more information. Support groups may also be available for further resources.
Description Last Updated: Aug 21, 2018