C1Q deficiency

C1q deficiency is a rare condition that affects the immune system. In people with this condition, the C1q protein, which plays a key role in the complement system (a group of proteins that help the immune system fight infections and clear dead cells), is either missing or abnormal. This can lead to problems in fighting infections and managing immune responses. Many people with C1q deficiency experience recurrent skin lesions and chronic infections. Nearly 93% of cases are linked to systemic lupus erythematosus (SLE) or SLE-like diseases. In some cases, the condition may also be associated with kidney problems, such as mesangial proliferative glomerulonephritis.

Common symptoms in people with C1q deficiency include repeated infections such as ear infections, meningitis, urinary tract infections, and infections in the mouth. Many individuals also develop skin problems like small blisters, dark patches, and areas of thinning skin that can worsen with exposure to light. Other symptoms may include cataracts, loss of eyelashes, eyebrows, and scalp hair, as well as blood in the urine and kidney inflammation.

C1q deficiency is caused by issues with the C1q protein. It can occur due to mutations in one of three genes: C1QA, C1QB, or C1QC. The condition follows an autosomal recessive inheritance pattern, which means that a person must inherit the mutated gene from both parents to develop the condition.

Treatment for C1q deficiency depends on the symptoms that a person experiences. Management may involve addressing the various infections and skin lesions. A notable recent development is the use of allogeneic hematopoietic stem cell transplantation, a procedure in which blood-forming stem cells from a genetically similar donor are given to help restore C1q production.

Information about prognosis is currently limited for this condition.

Research on C1q deficiency is ongoing. Recent studies have shown that allogeneic hematopoietic stem cell transplantation may help restore normal C1q production. Future research may continue to explore this treatment and other ways to manage symptoms effectively.