complement component 6 deficiency

Complement component 6 deficiency is a condition caused by mutations in the C6 gene that affect the body’s complement system, a key component of the immune response. Individuals with this condition have an inability to produce sufficient levels of complement C6, which is crucial for forming the membrane attack complex that helps eliminate certain bacterial pathogens. The condition typically presents in childhood, although the exact age of onset can vary, and both males and females are affected equally given its autosomal recessive inheritance. Precise prevalence data are not available, and understanding of the condition’s frequency in the population continues to evolve.

The clinical features of complement component 6 deficiency primarily involve abnormalities in complement function. Virtually all affected individuals exhibit reduced circulating CH50 activity and decreased levels of complement C6. In addition, a significant proportion, estimated between 30% and 79%, experience recurrent meningococcal disease, which may trigger the initial investigation and subsequent diagnosis. Not all individuals experience all features, and severity varies considerably between affected people.

This condition is caused by mutations in the C6 gene, which plays an essential role in the complement system by contributing to the formation of the membrane attack complex. Complement component 6 deficiency is inherited in an autosomal recessive pattern, meaning that an affected individual has received mutated copies of the gene from both parents. For families with a history of the condition, there is typically a 25% chance that any given pregnancy may result in an affected child. Genetic counseling is recommended to provide more detailed insights into recurrence risks and family planning options.

Currently, management focuses on supportive care and symptom management rather than disease-specific therapies, as there are no FDA-approved treatments for complement component 6 deficiency. Treatment is tailored to the individual and typically involves a multidisciplinary team to help manage infections and other complications. Patients often benefit from prompt treatment of infections and may require antibiotics as part of their supportive care. Genetic counseling is recommended, and patients should discuss treatment options with their healthcare team to determine the most appropriate strategies for their situation.

Outcomes for individuals with complement component 6 deficiency can vary depending on symptom severity, frequency of infections, and the timeliness of supportive care. With current standards of care, many individuals manage their condition well into adulthood, though recurrent episodes of meningococcal disease can complicate the course for some. Outcomes described in medical literature continue to evolve as standards of care improve, and it is important to recognize that severity and symptoms vary widely between individuals. Families may find it helpful to connect with genetic counselors and immunology specialists to discuss long-term management and support.